AUTONOMOUS VEHICLE TECHNOLOGY REPORT - 2020 The guide to understanding the current state of the art in hardware & software for self-driving ...

Page created by Tony Todd
 
CONTINUE READING
AUTONOMOUS VEHICLE TECHNOLOGY REPORT - 2020 The guide to understanding the current state of the art in hardware & software for self-driving ...
2020
AUTONOMOUS
VEHICLE
TECHNOLOGY
REPORT         The guide to understanding
               the current state of the art
               in hardware & software for
               self-driving vehicles.

sponsored by
AUTONOMOUS VEHICLE TECHNOLOGY REPORT - 2020 The guide to understanding the current state of the art in hardware & software for self-driving ...
For the people who
aim to create a better
version of the future.
AUTONOMOUS VEHICLE TECHNOLOGY REPORT - 2020 The guide to understanding the current state of the art in hardware & software for self-driving ...
Contributors                                         6

Introduction                                         10
How this report came to be: a collaborative effort   11

Levels of Autonomy                                   14

Sensing                                              17
Environmental mapping                                18
 Passive sensors                                     18
 Active Sensors                                      22
 Choice of Sensors                                   28
Geolocalization                                      32
 Maps                                                33

Thinking & Learning                                  35
SLAM and Sensor Fusion                               35
 Machine Learning Methods                            38
 Gathering Data                                      40
Path Planning                                        42

Acting                                               44
Architectures: Distributed versus Centralized        45
Power, Heat, Weight, and Size challenges             47

User experience                                      48
Inside the vehicle                                   51
The external experience                              53

Communication & Connectivity                         55
DSRC or C-V2X                                        59

Use case: Autonomous Racing                          62

Summary                                              66

About Nexperia                                       68

About Wevolver                                       70

References                                           72
AUTONOMOUS VEHICLE TECHNOLOGY REPORT - 2020 The guide to understanding the current state of the art in hardware & software for self-driving ...
Contributors
    Editor in Chief                                Jordan Sotudeh                                Akbar Ladak                                   Joakim Svennson
                                                                                                                                                                                               Cover Photographer                            Many thanks to
    Bram Geenen                                    Los Angeles, USA                              Bangalore, India                              Norrköping, Sweden                              Benedict Redgrove                             The people at Roborace, specifically Victo-
    Amsterdam, The Netherlands                     Senior Strategic Analyst at NASA Jet Pro-     Founder, CEO, Kaaenaat, which develops        Senior ADAS Engineer, Function Owner            London, United Kingdom                        ria Tomlinson and Alan Cocks.
    CEO Wevolver.                                  pulsion Laboratory.                           autonomous robots for logistics, retail and   Traffic Sign Recognition and Traffic Light      Benedict has a lifelong fascination with
                                                   Master International Science and Technol-     security use cases, as well as Advanced       Recognition at Veoneer.                         technology, engineering, innovation and       Edwin van de Merbel, Dirk Wittdorf, Petra
                                                   ogy Policy, Elliott School of International   Driver Assistance Systems (ADAS) for 2- &     MSc. Media Technology, Linköping Univer-        industry, and is a dedicated proponent of     Beekmans - van Zijll and all the other
    Editors                                        Affairs, Washington DC, USA.                  4- wheeler vehicles for chaotic driving       sity, Sweden.                                   modernism. This has intuitively led him       people at Nexperia for their support.
                                                                                                 conditions in Asia & Africa.                                                                  to capturing projects and objects at their
    Ali Nasseri                                    Matthew Nancekievill                          Master in Electrical Engineering, Georgia     Fazal Chaudry                                   most cutting edge. He has created an aes-     Our team at Wevolver; including Sander
    Vancouver, Canada                              Manchester, United Kingdom                    Institute of Technology.                      Headington, United Kingdom                      thetic of photography that is clean, pure     Arts, Benjamin Carothers, Seth Nuzum,
    Lab manager at the Programming Lan-            Postdoctoral researcher submersible ro-                                                     Product Development Engineer.                   and devoid of any miscellaneous informa-      Isidro Garcia, Jay Mapalad, and Richard
    guages for Artificial Intelligence (PLAI)      botics, University of Manchester, UK.         Zeljko Medenica                               Master of Science, Space Studies, Interna-      tion, winning him acclaim and numerous        Hulskes. Many thanks for the proofreads
    research group at the University of British    PhD. Electrical and Electronics Engineer-     Birmingham, Michigan, USA                     tional Space University, Illkirch Graffensta-   awards.                                       and feedback.
    Columbia.                                      ing, University of Manchester, UK.            Principal Engineer and Human Machine          den, France.                                    Redgrove has amassed a following and
    Previously Chair of the Space Generation       CEO Ice Nine Robotics.                        Interface (HMI) Team Lead at the US                                                           client base from some of the most ad-         The Wevolver community for their support,
    Advisory Council.                                                                            R&D Center of Changan, a major Chinese        Shlomit Hacohen                                 vanced companies in the world. A career       knowledge sharing, and for making us
    Cum Laude PhD. in Engineering Physics,         Jeremy Horne                                  automobile manufacturer. Previously led       Tel Aviv, Israel                                spent recording the pioneering technol-       create this report.
    Politecnico di Torino.                         San Felipe, Baja California, Mexico           research on novel and intuitive HMI for       VP of Marketing at Arbe Robotics; develop-      ogy of human endeavours has produce a
                                                   President Emeritus of the American Asso-      Advanced Driver Assistance Systems at         ing ultra high-resolution 4D imaging radar      photographic art form that gives viewers a    Many others that can’t all be listed here
    Adriaan Schiphorst                             ciation for the Advancement of Science,       Honda.                                        technology.                                     window into an often unseen world, such       have helped us in big or small ways. Thank
    Amsterdam, The Netherlands                     Southwest Division.                           PhD. in Electrical and Computer Engineer-     MBA at Technion, the Israel Institute of        as Lockheed Martin Skunk Works, UK MoD,       you all.
    Technology journalist.                         Science advisor and curriculum coordina-      ing from the University of New Hampshire.     Technology                                      European Space Agency, British Aerospace
    MSc Advanced Matter & Energy Physics at        tor at the Inventors Assistance Center.                                                                                                     and NASA. Whether capturing the U-2 re-       Beyond the people mentioned here we
    University of Amsterdam and the California     Ph.D. in philosophy from the University of    Maxime Flament                                Designer                                        connaissance pilots and stealth planes, the   owe greatly to the researchers, engineers,
    Institute of Technology.                       Florida, USA.                                 Brussels, Belgium                                                                             Navy Bomb Disposal Division or spending       writers, and many others who share their
    Previously editor at Amsterdam Science                                                       Chief Technology Officer, 5G Automotive       Bureau Merkwaardig                              time documenting the NASA’s past, present     knowledge online. Find their input in the
    Journal.                                       Drue Freeman                                  Association (5GAA)                            Amsterdam, The Netherlands                      and future, Benedict strives to capture       references.
                                                   Cupertino, California, USA                    PhD. in Wireless Communication Systems,       Award winning designers Anouk de                the scope and scale of advancements and
    Contributing Experts                           CEO of the Association for Corporate          Chalmers University of Technology, Göte-      l’Ecluse and Daphne de Vries are a creative     what they mean to us as human beings.         Media Partner
                                                   Growth, Silicon Valley.                       borg, Sweden.                                 duo based in Amsterdam. They are special-       His many awards include the 2009 AOP
    Norman di Palo                                 Former Sr. Vice President of Global                                                         ized in visualizing the core of an artistic     Silver, DCMS Best of British Creatives, and   Supplyframe
    Rome, Italy                                    Automotive Sales & Marketing for NXP          Mark A. Crawford Jr.                          problem. Bureau Merkwaardig initiates,          the Creative Review Photography Annual        Supplyframe is a network for electronics
    Robotics and Machine Learning researcher,      Semiconductors.                               Baoding City, China                           develops and designs.                           2003, 2008, and 2009.                         design and manufacturing. The company
    conducting research on machine learning        Board Director at Sand Hill Angels. Adviso-   Chief Engineer for Autonomous Driving                                                         At Wevolver we are a great fan of Bene-       provides open access to the world’s largest
    for computer vision and control at the Isti-   ry Board Member of automotive companies       Systems at Great Wall Motor Co.               Illustrations                                   dict’s work and how his pictures capture a    collection of vertical search engines,
    tuto Italiano di Tecnologia, Genova, Italia.   Savari and Ridar Systems, and Advisory        PhD. Industrial and Systems Engineering                                                       spirit of innovation. We’re grateful he has   supply chain tools, and online communi-
    Cum Laude MSc. Engineering in Artifi-          Board Member of Silicon Catalyst, a semi-     - Global Executive Track, at Wayne State      Sabina Begović                                  enabled us to use his beautiful images of     ties for engineering. Their mission is to
    cial Intelligence and Robotics, Sapienza       conductor focused incubator.                  University.                                   Padua, Italy                                    the Robocar to form the perfect backdrop      organize the world of engineering knowl-
    Università di Roma, and graduate of the Pi     Bachelor of Science in Electrical Engineer-   Previously Technical Expert at Ford.          Croation born Sabina is a visual and inter-     for this report.                              edge to help people build better hardware
    School of Artificial Intelligence.             ing, San Diego State University, MBA from                                                   action designer. She obtained a Master’s in                                                   products, and at Wevolver we support that
                                                   Pepperdine University, Los Angeles.           William Morris                                Visual and Communication Design at Iuav,                                                      aspiration and greatly appreciate that Sup-
                                                                                                 Detroit, Michigan, USA                        University of Venice, and a Masters in Art                                                    plyframe contributes to the distribution of
                                                                                                 Automotive engineer                           Education at the Academy of Applied Art,                                                      this report among their network.
                                                                                                                                               Rijeka, Croatia.

6                                                                                                                                                                                                                                                                                          7
AUTONOMOUS VEHICLE TECHNOLOGY REPORT - 2020 The guide to understanding the current state of the art in hardware & software for self-driving ...
“It’s been an enormously
    difficult, complicated
    slog, and it’s far more
    complicated and involved
    than we thought it would
    be, but it is a huge deal.”

    Nathaniel Fairfield,
    distinguished software
    engineer and leader of the
    ‘behavior team’ at Waymo,
    December 2019 [1]

8                                 9
AUTONOMOUS VEHICLE TECHNOLOGY REPORT - 2020 The guide to understanding the current state of the art in hardware & software for self-driving ...
Introduction
     Bram Geenen        Motorized transportation has changed       Therefore, this report’s purpose is to      How this report                             This report would not have been
     Editor in Chief,   the way we live. Autonomous vehicles       enable you to be up to date and un-                                                     possible without the sponsorship of
     CEO of Wevolver    are about to do so once more. This         derstand autonomous vehicles from a         came to be:                                 Nexperia, a semiconductor company
                        evolution of our transport - from hors-    technical viewpoint.                                                                    shipping over 90Bn components an-
                        es and carriages, to cars, to driverless   We have compiled and centralized the        a collaborative                             nually, the majority of which are with-
                        vehicles, - has been driven by both        information you need to understand                                                      in the automotive industry. Through
                        technical innovation and socioeco-         what technologies are needed to             effort                                      their support, Nexperia shows a
                        nomic factors. In this report we focus     develop autonomous vehicles. We will                                                    commitment to the sharing of objec-
                        on the technological aspect.               elaborate on the engineering consid-        Once the decision was made to create        tive knowledge to help technology
                                                                   erations that have been and will be         this report, we asked our communi-          developers innovate. This is the core
                        Looking at the state of autonomous         made for the implementation of these        ty for writers with expertise in the        of what we do at Wevolver.
                        vehicles at the start of the 2020s we      technologies, and we’ll discuss the         field, and for other experts who could
                        can see that impressive milestones         current state of the art in the industry.   provide input. A team of writers and        The positive impact these technol-
                        have been achieved, such as compa-                                                     editors crafted a first draft, leveraging   ogies could possibly have on both
                        nies like Waymo, Aptiv, and Yandex         This reports’ approach is to describe       many external references. Then, in a        individual lives, and our society and
                        offering autonomous taxis in dedicat-      technologies at a high level, to offer      second call-out to our community we         planet as a whole are an inspiring
                        ed areas since mid-2018. At the same       the baseline knowledge you need to          found many engineers and leaders            and worthwhile goal. At Wevolver
                        time, technology developers have run       acquire, and to use lots of references      from both commercial and academic           we hope this report provides the
                        into unforeseen challenges.                to help you dive deeper whenever            backgrounds willing to contribute           information and inspiration for you in
                                                                   needed.                                     significant amounts of their time           any way possible to be a part of that
                        Some industry leaders and experts                                                      and attention to providing extensive        evolution.
                        have scaled back their expectations,       Most of the examples in the report          feedback and collaborating with us
                        and others have spoken out against         will come from cars. However, indi-         to shape the current report through
                        optimistic beliefs and predictions.[2,3]   vidual personal transportation is not       many iterations. We owe much to
                        Gartner, a global research and advi-       the only area in which Autonomous           their dedication, and through their
                        sory firm, weighs in by now placing        Vehicles (AVs) will be deployed and         input this report has been able to
                        ‘autonomous vehicles’ in the Trough of     in which they will have a significant       incorporate views from across the
                        Disillusionment of their yearly Hype       impact. Other areas include public          industry and 11 different countries.
                        Cycle.[4]                                  transportation, delivery & cargo and
                                                                   specialty vehicles for farming and          Because this field continues to
                        The engineering community is less          mining. All of these come with their        advance, we don’t consider our work
                        affected by media hype: Over 22% of        own environment and specific usage          done. We intend to update this report
                        the engineers visiting the Wevolver        requirements that are shaping AV            into new editions regularly as new
                        platform do so to gain more knowl-         technology. At the same time, all of        knowledge comes available and our
                        edge on autonomous vehicle technol-        the technologies described in this re-      understanding of the topic grows.
                        ogy.[5] Despite how much topics like       port form the ingredients for autono-       You are invited to play an active role
                        market size and startup valuations         my, and thus will be needed in various      and contribute to this evolution, be it
                        have been covered globally by the          applications.                               through brief feedback or by submit-
                        media, many engineers have ex-                                                         ting significant new information and
                        pressed to our team at Wevolver that                                                   insights to our editorial team (info@
                        comprehensive knowledge to grasp                                                       wevolver.com), your input is highly
                        the current technical possibilities is                                                 appreciated and invaluable to further
                        still lacking.                                                                         the knowledge on this topic.

10                                                                                                                                                                                                   11
AUTONOMOUS VEHICLE TECHNOLOGY REPORT - 2020 The guide to understanding the current state of the art in hardware & software for self-driving ...
“Autonomous vehicles
     are already here – they’re
     just not very evenly
     distributed.”
     William Gibson,
     Science fiction writer,
     April 2019 [12]

12                                13
AUTONOMOUS VEHICLE TECHNOLOGY REPORT - 2020 The guide to understanding the current state of the art in hardware & software for self-driving ...
Levels of Autonomy
     When talking about autonomous ve-         Level 0 (L0):                             Level 2 (L2):                                           Level 3 (L3):                        Level 4 (L4):                                 Level 5 (L5):
     hicles, it is important to keep in mind   No automation                             Now both steering and accelera-                         Conditional automation: The sys-     These systems have high auto-                 Full automation, the vehicle can
     that each vehicle can have a range of                                               tion are simultaneously handled                         tem can drive without the need       mation and can fully drive them-              drive wherever, whenever.
     autonomous capabilities. To enable        Level 1 (L1):                             by the autonomous system. The                           for a human to monitor and re-       selves under certain conditions.
     classification of autonomous vehicles,    Advanced Driver Assistance Sys-           human driver still monitors the                         spond. However, the system might     The vehicle won’t drive if not all
     the Society Of Automotive Engineers       tems (ADAS) are introduced: fea-          environment and supervises the                          ask a human to intervene, so the     conditions are met.
     (SAE) International established its       tures that either control steering        support functions.                                      driver must be able to take con-
     SAE J3016™ “Levels of Automated           or speed to support the driver. For                                                               trol at all times.
     Driving” standard. Its levels range       example, adaptive cruise control
     from 0-5 and a higher number des-         that automatically accelerates and
     ignates an increase in autonomous         decelerates based on other vehi-
     capabilities.[6]                          cles on the road.

                                                                                                                                                                                                                                  Levels of driving automation summary.
                                                                                                                                                                                                                                  Adapted from SAE by Wevolver. [6]

                                                                                                                                                                         ZZ               Z ZZ Z
                                                                                                                                                                     Z                   ZZ

                                   0                  00             1                      11            2                  22        3                     33               4                    44             5                      55
                        NO AUTOMATION NO
                                       NOAUTOMATION
                                          AUTOMATION
                                              DRIVER ASSISTANCE
                                                              DRIVER
                                                               DRIVERASSISTANCE
                                                                      ASSISTANCE
                                                                       PARTIAL AUTOMATION
                                                                                      PARTIAL
                                                                                       PARTIALCONDITIONAL
                                                                                              AUTOMATION
                                                                                               AUTOMATIONAUTOMATION
                                                                                                            CONDITIONAL
                                                                                                             CONDITIONALAUTOMATION
                                                                                                                         AUTOMATION
                                                                                                                          HIGH AUTOMATIONHIGH
                                                                                                                                          HIGHAUTOMATION
                                                                                                                                               AUTOMATION
                                                                                                                                                   FULL AUTOMATIONFULL
                                                                                                                                                                   FULLAUTOMATION
                                                                                                                                                                        AUTOMATION

                                                             You monitor the environment.
                                                                                 You
                                                                                  Youmonitor
                                                                                       monitor
                                                                                           Youthe
                                                                                               the
                                                                                               areenvironment.
                                                                                                   environment.
                                                                                                   the driver, You
                                                                                                                 Youare
                                                                                                                     arethe
                                                                                                                         thedriver,
                                                                                                                            When
                                                                                                                             driver,system requests,
                                                                                                                                                  When
                                                                                                                                                   Whensystem
                                                                                                                                                        systemrequests,
                                                                                                                                                                requests,
                                                              even when automationeven
                                                                                   even
                                                                                     features
                                                                                        when
                                                                                         whenare
                                                                                              automation
                                                                                               automation
                                                                                                  turned on.
                                                                                                          features
                                                                                                           featuresare
                                                                                                                    areturned
                                                                                                                        turned
                                                                                                                             you
                                                                                                                              on.
                                                                                                                               on.must take control.
                                                                                                                                                  you
                                                                                                                                                   youmust
                                                                                                                                                      musttake
                                                                                                                                                            takecontrol.
                                                                                                                                                                 control.
                                                                                                                                                                    No requirement for you
                                                                                                                                                                                        No
                                                                                                                                                                                         Noto
                                                                                                                                                                                            requirement
                                                                                                                                                                                             requirement
                                                                                                                                                                                              take over control.
                                                                                                                                                                                                         for
                                                                                                                                                                                                          foryou
                                                                                                                                                                                                              youtototake
                                                                                                                                                                                                                      takeover
                                                                                                                                                                                                                           overcontrol.
                                                                                                                                                                                                                                control.

                                                                                                                                           System operates whenSystem
                                                                                                                                                                System
                                                                                                                                                                 specific
                                                                                                                                                                      operates
                                                                                                                                                                       operateswhen
                                                                                                                                                                                whenspecific
                                                                                                                                                                                      specific           System operates in allSystem
                                                                                                                                                                                                                               Systemoperates
                                                                                                                                                                                                                                       operatesininall
                                                                                                                                                                                                                                                    all
                                                                          System suports you driving.
                                                                                              System
                                                                                               Systemsuports
                                                                                                      suportsyou
                                                                                                              youdriving.
                                                                                                                  driving.                      conditions are met. conditions
                                                                                                                                                                     conditionsare
                                                                                                                                                                                aremet.
                                                                                                                                                                                   met.                      conditions             conditions
                                                                                                                                                                                                                                     conditions

                                                           Steering OR speed         Steering
                                                                                      SteeringOR
                                                                                               ORspeed
                                                                                                  speed
                                                             are automated.            are
                                                                                        areautomated.
                                                                                            automated.                                  Steering AND speed are
                                                                                                                                                             Steering
                                                                                                                                                               automated.
                                                                                                                                                            Steering  ANDspeed
                                                                                                                                                                     AND  speedare
                                                                                                                                                                                areautomated.
                                                                                                                                                                                    automated.

14                                                                                                                                                                                                                                                                        15
AUTONOMOUS VEHICLE TECHNOLOGY REPORT - 2020 The guide to understanding the current state of the art in hardware & software for self-driving ...
The context and environment (in-
     cluding rules, culture, weather, etc.)
     in which an autonomous vehicle
                                              Level 5 ADS have the same mobility
                                              as a human driver: an unlimited ODD.
                                              Designing the autonomous vehicle to
                                                                                                                                   Sensing
     needs to operate greatly influences      be able to adjust to all driving sce-
     the level of autonomy that can be        narios, in all road, weather and traffic
     achieved. On a German Autobahn, the      conditions is the biggest technical                                                  Because an autonomous vehicle oper-
     speed and accuracy of obstacle de-       challenge to achieve. Humans have                                                    ates in an (at least partially) unknown
     tection, and the subsequent decisions    the capability to perceive a large                                                   and dynamic environment, it simulta-
     that need to be made to change the       amount of sense information and                                                      neously needs to build a map of this
     speed and direction of the vehicle       fuse this data to make decisions us-                                                 environment and localize itself within
     need to happen within a few milli-       ing both past experience and our im-                                                 the map. The input to perform this
     seconds, while the same detection        agination. All of this in milliseconds.                                              Simultaneous Localization and Map-
     and decisions can be much slower         A fully autonomous system needs to                                                   ping (SLAM) process needs to come
     for a vehicle that never leaves a        match (and outperform) us in these                                                   from sensors and pre-existing maps
     corporate campus. In a similar matter,   capabilities. The question of how to                                                 created by AI systems and humans.
     the models needed to drive in sunny      assess the safety of such a system
     Arizona are more predictable than        needs to be addressed by legislators.
     those in New York City, or Banga-        Companies have banded together,
                                                                                                                                                                Static       Moving     Road       Lane      Traffic   Street
     lore. That also means an automated       like in the Automated Vehicle Safety                                                                             Objects       Objects   Markings   Markings   Lights    Signs
     driving system (ADS) capable of L3       Consortium, to jointly develop new
     automation in the usual circumstanc-     frameworks for safety.[10]
     es of e.g. Silicon Valley, might need
     to fall back to L2 functionality if it   Major automotive manufacturers,
     would be deployed on snowy roads         as well as new entrants like Google
     or in a different country.               (Waymo), Uber, and many startups
                                              are working on AVs. While design
     The capabilities of an autonomous        concepts differ, all these vehicles rely
     vehicle determine its Operational        on using a set of sensors to perceive
     Design Domain (ODD). The ODD             the environment, advanced software
     defines the conditions under which       to process input and decide the
     a vehicle is designed to function and    vehicle’s path and a set of actuators
     is expected to perform safely. The       to act upon decisions. [11] The next
     ODD includes (but isn’t limited to)      sections will review the technologies
     environmental, geographical, and         needed for these building blocks of
     time-of-day restrictions, as well as     autonomy.
     traffic or roadway characteristics.
     For example, an autonomous freight
     truck might be designed to transport
     cargo from a seaport to a distribu-
     tion center 30 Km away, via a specific
     route, in day-time only. This vehicles
     ODD is limited to the prescribed
     route and time-of-day, and it should
     not operate outside of it.[7–9]

                                                                                         Example of the variety of static and
                                                                                         moving objects that an autonomous
                                                                                         vehicle needs to detect and distinguish
                                                                                         from each other. Image: Wevolver,
                                                                                         based on a photo by Dan Smedley.

16                                                                                                                                                                                                                     17
AUTONOMOUS VEHICLE TECHNOLOGY REPORT - 2020 The guide to understanding the current state of the art in hardware & software for self-driving ...
Environmental                             Passive sensors                            This leads to higher noise susceptibil-
                                                                                          ity for CMOS sensors, such that CCD
     mapping                                   Due to the widespread use of object
                                               detection in digital images and vide-
                                                                                          sensors can create higher quality im-
                                                                                          ages. Yet, CMOS sensors use up to 100
                                               os, passive sensors based on camera        times less power than CCDs. Further-            LIDAR                                                                                     Ir Cameras

     In order to perceive a vehicle’s direct   technology were one of the first           more, they’re easier to fabricate using
     environment, object detection sensors     sensors to be used on autonomous           standard silicon production processes.
     are used. Here, we will make a dis-       vehicles. Digital cameras rely on CCD
     tinction between two sets of sensors:     (charge-coupled device) or CMOS            Most current sensors used for auton-
     passive and active. Passive sensors       (complementary metal-oxide semi-           omous vehicles are CMOS based and
                                                                                                                                          GNSS                                                                                   Long Range RADAR
     detect existing energy, like light or     conductor) image sensors which work        have a 1-2 megapixel resolution.[15]
     radiation, reflecting from objects in     by changing the signal received in the
     the environment, while active sensors     400-1100 nm wavelengths (visible to        While passive CMOS sensors are
     send their own electromagnetic            near infrared spectra) to an electric      generally used in the visual light
     signal and sense its reflection. These    signal.[13,14]                             spectrum, the same CMOS technology
                                                                                                                                                                                                                                  Short / Medium
     sensors are already found in automo-                                                 could be used in thermal imaging                 IMU                                                                                     Range RADAR
     tive products at Level 1 or 2, e.g. for   The surface of the sensor is broken        cameras which work in the infrared
     lane keeping assistance.                  down into pixels, each of which can        wavelengths of 780 nm to 1 mm.
                                               sense the intensity of the signal          They are useful sensors for detection
                                               received, based on the amount of           of hot bodies, such as pedestrians or
                                               charge accumulated at that location.       animals, and for peak illumination
                                               By using multiple sensors that are         situations such as the end of a tunnel,        Cameras                                                                                    Ultrasound
                                               sensitive to different wavelengths of      where a visual sensor will be blinded
                                               light, color information can also be       by the light intensity.[16]
                                               encoded in such a system.
                                                                                          In most cases, the passive sensor
                                               While the principle of operation of        suite aboard the vehicle consists of
                                               CCD and CMOS sensors are similar,          more than one sensor pointing in the
                                               their actual operation differs. CCD        same direction. These stereo camer-
                                               sensors transport charge to a specific     as can take 3D images of objects by
                                               corner of the chip for reading, while      overlaying the images from the differ-
                                               each pixel in a CMOS chip has its own      ent sensors. Stereoscopic images can
                                               transistor to read the interaction with    then be used for range finding, which
                                               light. Colocation of transistors with      is important for autonomous vehicle
                                               sensor elements in CMOS reduces its        application.
                                               light sensitivity, as the effective sur-
                                               face area of the sensor for interaction
                                               with the light is reduced.

                                                                                                                                    An example of typical sensors used to perceive the environment. Note that various vehicle
                                                                                                                                    manufacturers may use different combinations of sensors and might use all of the displayed
                                                                                                                                    sensors. For example, increasingly multiple smaller LIDAR sensors are being used, and long
                                                                                                                                    range backward facing RADAR can be incorporated to cover situations like highway lane
                                                                                                                                    changing and merging. The placing of the sensors can vary as well. Image: Wevolver

18                                                                                                                                                                                                                                                 19
The main benefits of passive sensors            Indeed, Tesla cars mount an array of      be done by using a rotating camera        “Once you solve cameras for vision, autonomy is
     are[17]:                                        cameras all around the vehicle to         that takes images at specific inter-
                                                     gather visual field information, and      vals, or by stitching the images of 4-6
                                                                                                                                         solved; if you don’t solve vision, it’s not solved
     •      High-resolution in pixels and            London based startup Wayve claims         cameras together through software.        … You can absolutely be superhuman with just
            color across the full width of its       that its cars which only rely on pas-     In addition, these sensors need a high
            field of view.                           sive optic sensors are safe enough for    dynamic range (the ability to image       cameras.”
     •      Constant ‘frame-rate’ across the         use in cities. The main shortcoming of    both highlights and dark shadows in a
            field of view.                           passive sensors is their performance      scene), of more than 100 dB,[22] giving   Elon Musk,
     •      Two cameras can generate a 3D            in low light or poor weather condi-       them the ability to work in various       2017 [19]
            stereoscopic view.                       tions; due to the fact that they do not   light conditions and distinguish be-
     •      Lack of transmitting source re-          have their own transmission source        tween various objects.
            duces the likelihood of interfer-        they cannot easily adapt to these
            ence from another vehicle.               conditions. These sensors also gen-       Dynamic range is measured in decibel
     •      Low cost due to matured tech-            erate 0.5-3.5 Gbps of data,[18] which     (dB); a logarithmic way of describing
            nology.                                  can be a lot for onboard processing       a ratio. Humans have a dynamic range      “At the moment, LIDAR lacks the capabilities to
     •      The images generated by these            or communicating to the cloud. It is      of about 200 dB. That means that in a
            systems are easy for users to            also more than the amount of data         single scene, the human eye can per-      exceed the capabilities of the latest technology in
            understand and interact with             generated by active sensors.              ceive tones that are about 1,000,000      radar and cameras.”
                                                                                               times darker than the brightest ones.
                                                     If a passive camera sensor suite          Cameras have a narrower dynamic
                                                                                                                                         Tetsuya Iijima,
                                                     is used on board an autonomous            range, though are getting better.
                                                     vehicle, it will likely need to see the
                                                                                                                                         General Manager of Advanced Technology De-
                                                     whole surrounding of the car. This can                                              velopment for Automated Driving, Nissan,
                                                                                                                                         May 2019 [20]

                                                                                                                                         “Let’s be candid, LIDAR is unaffordable in consumer
                                                                                                                                         vehicles, but if a lidar unit were available today
                                                                                                                                         that had good performance and was affordable, it
                                                                                                                                         would quietly show up in a Tesla car and this whole
         Gamma-Ray     X-Ray         UV   Visible    IR                 Microwave                                   Radio                hubbub would go away.”
                                                                                                                                         Bill Colleran,
                                                                                                                                         CEO, Lumotive,
                                                                                                                                         June 2019 [21]

         10-12        10-10        10-8             10-6       10-4         10-2         100         102          104          106
         Wavelength, λ (m)

                                                              RADAR
                                                  THERMAL CAMERAS
                                               LIDAR
                                          CAMERAS
                                                                                               The electromagnetic spectrum and its
                                                                                               usage for perception sensors .[16]

20                                                                                                                                                                                             21
Active Sensors                             Ultrasonic sensors (also referred to as    RADAR (RAdio Detection And Rang-                                             Time of flight principle, illustrated.
                                                                                                                                                                        Image: Wevolver.
                                                SONAR; SOund NAvigation Ranging)           ing) uses radio waves for ranging.
     Active sensors have a signal transmis-     use ultrasound waves for ranging and       Radio waves travel at the speed of                                           The distance can be calculated using the
     sion source and rely on the principle      are by far the oldest and lowest cost      light and have the lowest frequency                                          formula d=(v⋅t)/2. Where d is the distance,
                                                of these systems. As sound waves           (longest wavelength) of the electro-                                         v is the speed of the signal (the speed of
     environment. ToF measures the travel       have the lowest frequency (longest         magnetic spectrum. RADAR signals                                             sound for sound waves, and the speed of
     time of a signal from its source to a      wavelengths) among the sensors                                                   -                                      light for electromagnetic waves) and t is
                                                used, they are more easily disturbed.      rials that have considerable electrical                                      the time for the signal to go to reach the
                                                                                                                                                                        object and reflect back. This calculation
     the signal to return.                      This means the sensor is easily            conductivity, such as metallic objects.
                                                                                                                                                                        method is the most common but has lim-
                                                affected by adverse environmental          Interference from other radio waves                                          itations and more complex methods have
     The frequency of the signal used de-       conditions like rain and dust. Inter-      can affect RADAR performance, while                                          been developed; for example, using the
     termines the energy used by the sys-       ference created by other sound waves       transmitted signals can easily bounce                                        phase-shift in a returning wave. [23]
     tem, as well as its accuracy. Therefore,   can affect the sensor performance          off curved surfaces, and thus the
     determining the correct wavelength         as well and needs to be mitigated by       sensor can be blind to such objects.
     plays a key role in choosing which         using multiple sensors and relying on      At the same time, using the bouncing
     system to use.                             additional sensor types. In addition, as   properties of the radio waves can
                                                sound waves lose energy as distance        enable a RADAR sensor to ‘see’ beyond
                                                increases, this sensor is only effective   objects in front of it. RADAR has less-
                                                over short distances such as in park       er abilities in determining the shape
                                                assistance. More recent versions rely      of detected objects than LIDAR.[25]
                                                on higher frequencies, to reduce the                                                                             Signal in
                                                likelihood of interference.[24]                                             -
                                                                                           DAR are its maturity, low cost, and
                                                                                           resilience against low light and bad
                                                                                           weather conditions. However, radar
                                                                                           can only detect objects with low
                                                                                           spatial resolution and without much
                                                                                           information about the spatial shape
                                                                                           of the object, thus distinguishing
                                                                                           between multiple objects or separat-
                                                                                           ing objects by direction of arrival can
                                                                                           be hard. This has relegated radars to
                                                                                           more of a supporting role in automo-      Signal out
                                                                                           tive sensor suites.[17]

                                                                                                                                       Di
                                                                                                                                         sta
                                                                                                                                            nc
                                                                                                                                              em
             “We need more time for the car to re-                                                                                              ea
                                                                                                                                                     su
             act, and we think imaging radar will be                                                                                                    re   d
             a key to that.”
             Chris Jacobs, Vice President of Autonomous Transporta-
             tion and Automotive Safety, Analog Devices Inc,
             January 2019 [26]

22                                                                                                                                                                                                                    23
“Almost everything is in R&D, of which 95 per-      Imaging radar is particularly interest-   LIDAR Systems that do not use any
                                                         ing for autonomous cars. Unlike short     mechanical parts are referred to as
     cent is in the earlier stages of research, rather   range radar which relies on 24GHz ra-     solid-state, and sometimes as ‘LIDAR-
     than actual development, the development stage      dio waves, imaging radar uses higher      on-a-chip.’
                                                         energy 77-79 GHz waves. This allows
     is a huge undertaking — to actually move it to-     the radar to scan a 100 degree field      Flash LIDARS are a type of solid-state
     wards real-world adoption and into true series      of view for up to a 300 m distance.       LIDARS that diffuse their laser beam
                                                         This technology eliminates former         to illuminate an entire scene in one
     production vehicles. Whoever is able to enable      resolution limitations and generates      flash. The returning light is captured
     true autonomy in production vehicles first is go-   a true 4D radar image of ultra-high       by a grid of tiny sensors. A major chal-
                                                         resolution.[15,26,27]                     lenge of Flash LIDARS is accuracy.[30]
     ing to be the game changer for the industry. But
     that hasn’t happened yet.”                          LIDAR (LIght Detection And Ranging)
                                                         uses light in the form of a pulsed
                                                                                                   Phased-Array LIDARS are another
                                                                                                   solid-state technology that is under-
                                                         laser. LIDAR sensors send out 50,000      going development. Such systems
     Austin Russell, founder and CEO of                  - 200,000 pulses per second to cover      feed their laser beam into a row of
     Luminar, June 2019 [21]                             an area and compile the returning         emitters that can change the speed
                                                         signals into a 3D point cloud. By         and phase of the light that passes
                                                         comparing the difference in consec-       through.[31] The laser beam gets
                                                         utive perceived point clouds, objects     pointed by incrementally adjusting
                                                         and their movement can be detected        the signal’s phase from one emitter to
                                                         such that a 3D map, of up to 250m in      the next.
                                                         range, can be created.[28]
                                                                                                   Metamaterials: A relatively new
                                                         There are multiple approaches to          development is to direct the laser by
                                                         LIDAR technology:                         shining it onto dynamically tunable
                                                                                                   metamaterials. Tiny components on
                                                         Mechanical scanning LIDARS use            these artificially structured metas-
                                                         rotating mirrors and/or mechanically      urfaces can be dynamically tuned to
                                                         rotate the laser. This setup provides a   slow down parts of the laser beam,
                                                         wide Field Of Vision but is also rela-    which through interference results
                                                         tively large and costly. This technolo-   in a beam that’s pointing in a new
                                                         gy is the most mature.                    direction. Lumotive, a startup funded
                                                                                                   by Bill Gates, claims its Metamaterial
                                                         Microelectromechanical mirrors            based LIDARS can scan 120 degrees
                                                         (MEMS) based LIDARS distribute            horizontally and 25 degrees vertically.
                                                         the laser pulses via one or multiple      [32]

                                                         tiny tilting mirrors, whose angle is
                                                         controlled by the voltage applied to
                                                         them. By substituting the mechanical
                                                         scanning hardware with an electro-
                                                         mechanical system, MEMS LIDARS can
                                                         achieve an accurate and power-ef-
                                                         ficient laser deflection, that is also
                                                         cost-efficient.[29]

                                                         LIDAR provides a 3D point cloud of the environment.
                                                         Image : Renishaw

24                                                                                                                                            25
Interference from a source with the        Among the three main active, ToF
     same wavelength, or changes in             based systems, SONAR is mainly used
     reflectivity of surfaces due to wet-       as a sensor for very close proximity
     ness can affect the performance of         due to the lower range of ultrasound
     LIDAR sensors. LIDAR performance           waves. RADAR cannot make out
     can also be affected by external light,    complex shapes, but it is able to see
     including from other LIDARS.[33] While     through adverse weather such as rain
     traditional LIDAR sensors use 900 nm       and fog. LIDAR can better sense an
     wavelengths, new sensors are shifting      object’s shape, but is shorter range
     to 1500 nm enabling the vehicle to         and more affected by ambient light
     see objects 150-250 m away.[26,28]         and weather conditions. Usually two
                                                active sensor systems are used in
     LIDAR has the benefits of having a         conjunction, and if the aim is to only
     relatively wide field of vision, with      rely on one, LIDAR is often chosen.
     potentially full 360 degree 3D cover-      Secondly, active sensors are often
     age (depending on the type of LIDAR        used in conjunction with passive
     chosen). Furthermore, it has a longer      sensors (cameras).
     range, more accurate distance esti-
     mates compared to passive (optical)
     sensors and lower computing cost.[17]
     Its resolution however, is poorer and
     laser safety can put limits on the laser
     power used, which in turn can affect
     the capabilities of the sensor.

     These sensors have traditionally been
     very expensive, with prices of tens of
     thousands of dollars for the iconic
     rooftop mounted 360 degree units.
     However, prices are coming down:                                                                                             Long range RADAR           Cameras                   LIDAR                     Short / Medium         Ultrasound
                                                                                                                                  Object detection,          A combination of          3D environment mapping,   range RADAR            Close range object
     Market leader Velodyne announced in
                                                                                                                                  through rain, fog, dust.   cameras for short-long    object detection.         Short-mid range        detection. For objects
     January 2020 a Metamaterials LIDAR                                                                                                                      range object detection.
                                                                                                                                  Signal can bounce                                                              object detection.      entering your lane.
     that should ship for $100, albeit offer-                                                                                     around/underneath          Broad spectrum of use                               Inc. side and rear     For parking.
     ing a narrower field of vision (60°                                                                                          vehiclesin front that
                                                                                                                                                             cases: from distant                                 collision avoidance.
     horizontal x 10° vertical) and shorter                                                                                                                  feature perception to
                                                                                                                                  obstruct view.
                                                                                                                                                             cross traffic detection.
     range (100m).[34,35]                                                                                                                                    Road sign recognition.

                                                                                         Various object detection and mapping
                                                                                         sensors are used for various purposes,
                                                                                         and have complementary capabilities
                                                                                         and ranges. Image: Wevolver

26                                                                                                                                                                                                                                                           27
Choice of Sensors                            The following technical factors         Vehicle manufacturers use a
                                                  affect the choice of sensors:           mixture of optical and ToF sen-
     While all the sensors presented have                                                 sors, with sensors strategically         Comparison of various sensors used in autonomous vehicles. [14,18,26,36–38]
     their own strengths and shortcom-        •   The scanning range, determining         located to overcome the short-
     ings, no single one would be a viable        the amount of time you have to          comings of the specific technol-
     solution for all conditions on the           react to an object that is being        ogy. By looking at their setup we
     road. A vehicle needs to be able to          sensed.                                 can see example combinations
     avoid close objects, while also sens-    •   Resolution, determining how             used for perception:                                              Measurement                                                Data rate
     ing objects far away from it. It needs       much detail the sensor can give                                                 Sensor                                                     Cost ($)
                                                                                                                                                            distance (m)                                                (Mbps)
     to be able to operate in different           you.                                •   Tesla’s Model S uses a forward
     environmental and road conditions        •   Field of view or the angular res-       mounted radar to sense the
     with challenging light and weather           olution, determining how many           road, 3 forward facing cameras
                                                                                                                                  Camera                        0-250                        4–200                    500-3500
     circumstances. This means that to            sensors you would need to cover         to identify road signs, lanes and
     reliably and safely operate an auton-        the area you want to perceive.          objects, and 12 ultrasonic sensors
     omous vehicle, usually a mixture of      •   Ability to distinguish between          to detect nearby obstacles around
     sensors is utilized.                         multiple static and moving ob-          the car                                 Ultrasound                   0.02-10                       30-400                     < 0.01
                                                  jects in 3D, determining the num-   •   Volvo-Uber uses a top mounted
                                                  ber of objects you can track.           360 degree Lidar to detect road
                                              •   Refresh rate, determining how           objects, short and long range
                                                  frequently the information from         optical cameras to identify road        RADAR                        0.2-300                       30-400                     0.1-15
                                                  the sensor is updated.                  signals and radar to sense close-
                                              •   General reliability and accuracy        by obstacles
                                                  in different environmental con-     •   Waymo uses a 360 degree LIDAR
                                                  ditions.                                to detect road objects, 9 visual        LIDAR                       Up to 250                  1,000-75,000                  20-100
                                              •   Cost, size and software compat-         cameras to track the road and a
                                                  ibility.                                radar for obstacle identification
                                              •   Amount of data generated.               near the car.
                                                                                      •   Wayve uses a row of 2.3-meg-         Note that these are typical ranges and more extreme values exist. For example, Arbe Robotics’ RADAR can
                                                                                          apixel RGB cameras with high-dy-     generate 1GBps depending on requirements from OEMs. Also note that multiple low costs sensors can be
                                                                                          namic range, and satellite naviga-   required to achieve comparable performance to high-end sensors.
                                                                                          tion to drive autonomously.[39]

28                                                                                                                                                                                                                                       29
Different Approaches                                                                                                              3x Forward Facing Cameras (Wide, Main, Narrow)           Forward Looking Side Cameras            Rear View Camera
     by Tesla, Volvo-Uber, and Waymo:

     Tesla Model S. Volvo-Uber XC90.Way-       Volvo provides a base vehicle with
     mo Chrysler Pacifica[36, 40-45] Images:   pre-wiring and harnessing for Uber
     adapted from Tesla, Volvo, Waymo, by      to directly plug in its own self-driv-
     Wevolver.                                 ing hardware, which includes the rig
                                               with LIDAR and cameras on top of the
     Companies take different approaches       vehicle.
     to the set of sensors used for autono-
     my, and where they are placed around
     the vehicle.

     Tesla’s sensors contain heating to
     counter frost and fog, Volvo’s camer-
     as come equipped with a water-jet
     washing system for cleaning their
     nozzles, and the cone that contains
     the cameras on Waymo’s Chrysler has
     water jets and wipers for cleaning.

                                                                                                                            Forward Facing RADAR              Rearward Looking Side Cameras              12 Ultrasonics around the vehicle

                                Uber’s Hardware:
                                    Forward Facing Cameras      LIDAR         Side and Rear Cameras

                                                                                                                                  4x RADAR         Long-range LIDAR   360° Cameras      Audio       2x Short-range LIDAR       2x Mid-range LIDAR

     Volvo’s Hardware:
         RADAR, front & back     Forward Facing Cameras            Side Cameras    Ultrasound, front & back   Rear Camera

30                                                                                                                                                                                                                                                     31
Geolocalization                           accuracy can be achieved using mul-
                                               ti-constellation; where the receiver
                                                                                            In the absence of additional signals
                                                                                            or onboard sensors, dead-reckoning
                                                                                                                                                                    Maps
                                               leverages signals from multiple GNSS         may be used, where the car’s naviga-                                    Today, map services such as Google
     Once the autonomous vehicle has           systems. Furthermore, accuracy can be        tion system uses wheel circumference,                                   Maps are widely used for navigation.
     scanned its environment, it can find      brought down to ~ 1cm levels using           speed, and steering direction data to                                   However, autonomous vehicles will
     its location on the road relative to      additional technologies that augment         calculate a position from occasion-                                     likely need a new class of high defi-
     other objects around it. This informa-    the GNSS system.                             ally received GPS data and the last                                     nition (HD) maps that represent the
     tion is critical for lower-level path                                                  known position.[52] In a smart city                                     world at up to two orders of magni-
     planning to avoid any collisions with     To identify the position of the car, all     environment, additional navigational                                    tude more detail. With an accuracy of
     objects in the vehicle’s immediate        satellite navigation systems rely on         aid can be provided by transponders                                     a decimeter or less, HD maps increase
     vicinity.                                 the time of flight of a signal between       that provide a signal to the car; by                                    the spatial and contextual awareness
                                               the receiver and a set of satellites.        measuring its distance from two or        “If we want to have           of autonomous vehicles and provide
     On top of that, in most cases the user    GNSS receivers triangulate their po-         more signals the vehicle can find its                                   a source of redundancy for their
     communicates the place they would         sition using their calculated distance       location within the environment.
                                                                                                                                      autonomous cars               sensors.
     like to go to in terms of a geograph-     from at least four satellites.[48] By con-                                             everywhere, we have
     ical location, which translates to a      tinuously sensing, the path of the ve-                                                 to have digital maps          By triangulating the distance from
     latitude and longitude. Hence, in addi-   hicle is revealed. The heading of the                                                                                known objects in a HD map, the
     tion to knowing its relative position     vehicle can be determined using two                                                    everywhere.”                  precise localization of a vehicle can
     in the local environment, the vehicle     GNSS antennas, by using dedicated
     needs to know its global position on      onboard sensors such as a compass,                                                     Amnon Shashua,
                                                                                                                                      Chief Technology Officer at
     Earth in order to be able to determine    or it can be calculated based on input                                                 Mobileye, 2017 [55]
     a path towards the user’s destination.    from vision sensors.[49]

     The default geolocalization method        While accurate, GNSS systems are
     is satellite navigation, which provides   also affected by environmental fac-
     a general reference frame for where       tors such as cloud cover and signal
     the vehicle is located on the planet.     reflection. In addition, signals can be
     Different Global Navigation Satellite     blocked by man-made objects such as
     Systems (GNSS) such as the American       tunnels or large structures. In some
     GPS, the Russian GLONASS, the Euro-       countries or regions, the signal might
     pean Galileo or the Chinese Beidou        also be too weak to accurately geolo-
     can provide positioning information       cate the vehicle.
     with horizontal and vertical resolu-
     tions of a few meters.                    To avoid geolocalization issues, an
                                               Inertial Measurement Unit (IMU) is
     While GPS guarantees a global signal      integrated with the system.[50,51] By
     user range error (URE) of less than 7.8   using gyroscopes and accelerometers,
     m, its signal’s actual average range      such a unit can extrapolate the data
     error has been less than 0.71 m. The      available to estimate the new loca-
     real accuracy for a user however, de-     tion of the vehicle when GNSS data is
     pends on local factors such as signal     unavailable.
     blockage, atmospheric conditions, and
     quality of the receiver that’s used.
     [46]
          Galileo, once fully operational,
     could deliver a < 1m URE.[47] Higher

                                                                                  A 3D HD map covering an intersection. Image: Here

32                                                                                                                                                                                                          33
be determined. Another benefit is
     that the detailed information a high
     definition map contains could narrow
                                                 As another example, London based
                                                 startup Wayve only uses standard
                                                 sat-nav and cameras. They aim to
                                                                                                                             Thinking & Learning
     down the information that a vehicle’s       achieve full autonomy by using
     perception system needs to acquire,         imitation learning algorithms to copy
     and enable the sensors and software         the behavior of expert human drivers,                                       Based on the raw data captured            SLAM and                               In order to perform SLAM more accu-
     to dedicate more efforts towards            and consequently using reinforcement                                        by the AV’s sensor suite and the                                                 rately, sensor fusion comes into play.
     moving objects.[53]                         learning to learn from each inter-                                          pre-existing maps it has access to,       Sensor Fusion                          Sensor fusion is the process of com-
                                                 vention of their human safety driver                                        the automated driving system needs                                               bining data from multiple sensors
     HD maps can represent lanes, geome-         while training the model in autono-                                         to construct and update a map of          SLAM is a complex process because      and databases to achieve improved
     try, traffic signs, the road surface, and   mous mode.[58]                                                              its environment while keeping track       a map is needed for localization and   information. It is a multi-level pro-
     the location of objects like trees. The                                                                                 of its location in it. Simultaneous       a good position estimate is needed     cess that deals with the association,
     information in such a map is repre-         Researchers from MIT’s Computer                                             localization and mapping (SLAM) al-       for mapping. Though long consid-       correlation, and combination of data,
     sented in layers, with generally at         Science and Artificial Intelligence                                         gorithms let the vehicle achieve just     ered a fundamental chicken-or-egg      and enables to achieve less expen-
     least one of the layers containing 3D       Laboratory (CSAIL) also took a                                              that. Once its location on its map is     problem for robots to become au-       sive, higher quality, or more relevant
     geometric information of the world in       ‘map-less’ approach and developed a                                         known, the system can start planning      tonomous, breakthrough research in     information than when using a single
     high detail to enable precise calcu-        system that uses LIDAR sensors for                                          which path to take to get from one        the mid-1980s and 90s solved SLAM      data source alone.[64]
     lations.                                    all aspects of navigation, only relying                                     point to another.                         on a conceptual and theoretical
                                                 on GPS for a rough location estimate.                                                                                 level. Since then, a variety of SLAM
     Challenges lie in the large efforts to      [59–61]
                                                                                                                                                                       approaches have been developed, the
     generate high definition maps and                                                                                                                                 majority of which uses probabilistic
     keep them up to date, as well as in                                                                                                                               concepts.[62,63]
     the large amount of data storage and
     bandwidth it takes to store and trans-
     fer these maps.[54]

     Most in the industry express HD maps
     to be a necessity for high levels of
     autonomy, in any case for the near                                                                                                    SENSING & DATA INPUT                 COMPUTATION & DECISION MAKING               ACT & CONTROL
     future as they have to make up for                                                                                                                                                                                      THE VEHICLE
     limited abilities of AI. However, some
                                                                                                                                   Cameras (inc. Thermal Cameras)
     disagree or take a different approach.
                                                                                                                                   RADAR
     According to Elon musk Tesla “briefly
     barked up the tree of high precision                                                                                          LIDAR                                                                                      Steering
     lane line [maps], but decided it wasn’t
                                                                                                                                   Ultrasound Sensors                              Simultaneous                               Accelerating
     a good idea.”[56] In 2015 Apple, for                                                                                                                                           Localization         Planning
     its part, patented an autonomous                                                                                              IMU
                                                                                                                                                                                        And
                                                                                                                                                                                                                              Braking
                                                                                                                                                                                      Mapping
     navigation system that lets a vehicle
     navigate without referring to exter-                                                                                          GNSS                                                                                       Signalling
     nal data sources. The system in the
     patent leverages AI capabilities and                                                  “The need for dense                     Map Data
     vehicle sensors instead.[57]
                                                                                           3-D maps limits                         Vehicle-to-Vehicle Communication

                                                                                           the places where                        Vehicle-to-Infrastructure Communication
                                                                                           self-driving cars can
                                                                                           operate.”
                                                                                           Daniela Rus,                                                                                                               The complex computation and
                                                                                           director of MIT’s Computer                                                                                                 decision making environment of
                                                                                           Science and Artificial Intelli-                                                                                            an autonomous vehicle.[65]
                                                                                           gence Laboratory (CSAIL), 2018                                                                                             Image: Wevolver

34                                                                                                                                                                                                                                                     35
For the all processing and decision                                                                                                The question which approach is best       First, we’ll review how the data from        es the transformation between the
     making required to go from sensor                                                                                                  for AVs is an area of ongoing debate.     the sensors is processed to reach a          two point clouds, which enables to
     data to motion in general two differ-                                                                                              The traditional, and most common          decision regarding the robotic vehi-         calculate the translation and rotation
     ent AI approaches are used [66]:                                                                                                   approach consists of decomposing          cle’s motion. Depending on the differ-       the vehicle had.
                                                                                                                                        the problem of autonomous driv-           ent sensors used onboard the vehicle,
     1.   Sequentially, where the driving                                                                                               ing into a number of sub-problems         different software schemes can be            While useful, the preceding ap-
          process is decomposed into com-                                                                                               and solving each one sequentially         used to extract useful information           proaches consume much computing
          ponents of a hierarchical pipeline.                                                                                           with a dedicated machine learning         from the sensor signals.                     time, and cannot easily be scaled
          Each step (sensing, localization                                                                                              algorithm technique from computer                                                      to the case of a self-driving vehicle
          and mapping, path planning,                                                                                                   vision, sensor fusion, localization,      There are several algorithms that            operating in a continuously changing
          motion control) is handled by a                                                                                               control theory, and path planning.[67]    can be used to identify objects in           environment. That is where machine
          specific software element, with                                                                                                                                         an image. The simplest approach              learning comes into play, relying on
          each component of the pipeline                                                                                                End-to-End (e2e) learning increas-        is edge detection, where changes             computer algorithms that have al-
          feeding data to the next one, or                                                                                              ingly gets interest as a potential        in the intensity of light or color in        ready learned to perform a task from
     2.   An End-to-End solution based on                                                                                               solution to the challenges of the         different pixels are assessed.[69] One       existing data.
          deep learning that takes care of                                                                                              complex AI systems for autonomous         would expect pixels that belong to
          all these functions.                                                                                                          vehicles. End-to-end (e2e) learning       the same object to have similar light
                                                                                                                                        applies iterative learning to a com-      properties; hence looking at chang-
                                                                                                                                        plex system as a whole, and has been      es in the light intensity can help
                                                                                                                                        popularized in the context of deep        separate objects or detect where one
                                                                                                                                        learning. An End-to-End approach          object turns to the next. The problem
                                                                                                                                        attempts to create an autonomous          with this approach is that in low light
                                                                                                                                        driving system with a single, com-        intensity (say at night) the algorithm
                                                                                                                                        prehensive software component that        cannot perform well since it relies on
                                                                                                                                        directly maps sensor inputs to driving    differences in light intensity. In addi-
                                                                                                                                        actions. Because of breakthroughs         tion, as this analysis has to be done
                                                                                                                                        in deep learning the capabilities of      on each shot and on multiple pixels,
                                                                                                                                        e2e systems have increased as such        there is a high computational cost.
                                                                                                                                        that they are now considered a viable
                                                                                                                                        option. These systems can be created      LIDAR data can be used to compute
      Perception &            High-Level                        Behavior             Motion Controllers                  Autonomy       with one or multiple different types      the movement of the vehicle with
                        +                          +                            +                               =
      Localization           Path Planning                     Arbitration                                                              of machine learning methods, such         the same principle. By comparing
                                                            (low-level path                                                             as Convolutional Neural Networks or       two point clouds taken at consecu-
                                                               planning)                                                                Reinforcement Learning, which we          tive instants, some objects will have
                                                                                                                                        will elaborate on later in this report.   moved closer or further from the
                                                                                                                                        [67,68]
                                                                                                                                                                                  sensor. A software technique called
                                                                                                                                                                                  iterative closest point iteratively revis-
                                                       //

                                          End2End Learning                                                      =        Autonomy

                                                Two main approaches to the AI architecture of autonomous vehicles: 1) sequential per-
                                                ception-planning-action-pipelines 2) an End2End system.[66]
                                                Image: Wevolver

36                                                                                                                                                                                                                                                                      37
Machine Learning                         CNNs are mainly used to process              RNNs are powerful tools when work-        These methods don’t necessarily sit in
     Methods                                  images and spatial information to
                                              extract features of interest and identi-
                                                                                           ing with temporal information such
                                                                                           as videos. In these networks the out-
                                                                                                                                     isolation. For example, companies like
                                                                                                                                     Tesla rely on hybrid forms, which try
     Different types of machine learning      fy objects in the environment. These         puts from the previous steps are fed      to use multiple methods together to
     algorithms are currently being used      neural networks are made of a convo-         into the network as input, allowing       increase accuracy and reduce compu-
     for different applications in autono-    lution layer: a collection of filters that   information and knowledge to persist      tational demands.[77,78]
     mous vehicles. In essence, machine       tries to distinguish elements of an im-      in the network and be contextualized.
     learning maps a set of inputs to a set   age or input data to label them. The         [72–74]
                                                                                                                                     Training networks on several tasks
     of outputs, based on a set of training   output of this convolution layer is fed                                                at once is a common practice in
     data provided. Convolutional Neural      into an algorithm that combines them         DRL combines Deep Learning (DL)           deep learning, often called multi-task
     Networks (CNN), Recurrent Neural         to predict the best description of an        and Reinforcement Learning. DRL           training or auxiliary task training. This
     Networks (RNN) and Deep Reinforce-       image. The final software component          methods let software-defined ‘agents’     is to avoid overfitting, a common
     ment Learning (DRL) are the most         is usually called an object classifier,      learn the best possible actions to        issue with neural networks. When a
     common deep learning methodolo-          as it can categorize an object in the        achieve their goals in a virtual en-      machine learning algorithm is trained
     gies applied to autonomous driving.      image, for example a street sign or          vironment using a reward function.        for a particular task, it can become
     [66]
                                              another car.[69–71]                          These goal-oriented algorithms learn      so focused imitating the data it is
                                                                                           how to attain an objective, or how to     trained on that its output becomes
                                                                                           maximize along a specific dimension       unrealistic when an interpolation or
                                                                                           over many steps. While promising, a       extrapolation is attempted. By train-
                                                                                           challenge for DRL is the design of the    ing the machine learning algorithm
                                                                                           correct reward function for driving a     on multiple tasks, the core of the
                                                                                           vehicle. Deep Reinforcement Learning      network will specialize in finding
                                                                                           is considered to be still in an early     general features that are useful for
                                                                                           stage regarding application in auton-     all purposes instead of specializing
                                                                                           omous vehicles.[75,76]                    only on one task. This can make the
                                                                                                                                     outputs more realistic and useful for
                                                                                                                                     applications.

                                               Algorithms turn input from sensors into object classifications and a map of the environment.
                                               Image: Wayve

38                                                                                                                                                                               39
Gathering Data                             One way to gather data is by using a
                                                prototype car. These cars are driven
     In order for these algorithms to be        by a driver. The perception sensors
     used, they need to be trained on data      onboard are used to gather informa-
     sets that represent realistic scenarios.   tion about the environment. At the
     With any machine learning process, a       same time, an on-board computer will
     part of the data set is used for train-    record sensors readings coming from
     ing, and another part for validation       the pedals, the steering wheel, and all
     and testing. As such, a great amount       other information that can describe
     of data is annotated by autonomous         how the driver acts. Due to the large
     vehicle companies to achieve this          amount of data that needs to be
     goal.[77] Many datasets, with semantic     gathered and labelled by humans,
     segmentation of street objects, sign       this is a costly process. According
     classification, pedestrian detection       to Andrej Karpathy, Director of AI at
     and depth prediction, have been            Tesla, most of the efforts in his group
     made openly available by researchers       are dedicated to getting better and
     and companies including Aptiv, Lyft,       better data.[77]
     Waymo, and Baidu. This has signifi-
     cantly helped to push the capabilities     Alternatively, simulators may be used.
     of the machine learning algorithms         “Current physical testing isn’t enough;
     forward.[79–81]                            therefore, virtual testing will be
                                                required,” says Jamie Smith, Director
                                                of Global Automotive Strategy at
                                                National Instruments.[82] By building
                                                realistic simulators, software compa-
                                                nies can create thousands of virtual
                                                scenarios. This brings the cost of data
                                                acquisition down but introduces the
                                                problem of realism: these virtual
                                                scenarios are defined by humans and
                                                are less random that what a real vehi-
                                                cle goes through. There is growing
                                                research in this area, called sim-to-
                                                real transfer, that studies methods to
                                                transfer the knowledge gathered in
                                                simulation in the real world.[83]

                                                Using all the data from the sensors
                                                and these algorithms, an autonomous
                                                vehicle can detect objects surround-
                                                ing it. Next, it needs to find a path to
     “We have quite a                           follow.
     good simulation, too,                                                                 “At Waymo, we’ve
     but it just does not                                                                  driven more than 10
     capture the long tail                                                                 million miles in the
     of weird things that                                                                  real world, and over
     happen in the real                                                                    10 billion miles in
     world.”                                                                               simulation.”
     Elon Musk,                                                                            Waymo CTO Dmitri Dolgov,   Simulators are used to explore thousands of varia-
     April 2019 [84]                                                                       July 2019 [85]             ble scenarios. Image: Autoware.AI

40                                                                                                                                                                         41
Path Planning                              Training neural networks and infer-                                                    “In most cases, if you look at what went wrong
                                                ence during operations of the vehicle
                                                requires enormous computing power.
                                                                                                                                       during a disengagement [the moment when
     With the vehicle knowing the objects       Until recently, most machine learning                                                  the AV needs human intervention - note by
     in its environment and its location,       tasks were executed on cloud-based
     the large scale path of the vehicle can    infrastructure with excessive comput-                                                  editor], the role of hardware failure is 0.0 per-
     be determined by using a voronoi di-       ing power and cooling. With autono-                                                    cent. Most of the time, it’s a software failure,
     agram (maximizing distance between         mous vehicles, that is no longer possi-
     vehicle and objects), an occupancy         ble as the vehicle needs to be able to                                                 that is, software failing to predict what the
     grid algorithm, or with a driving corri-   simultaneously react to new data. As                                                   vehicles are gonna be doing or what the pe-
     dors algorithm.[86] However, these tra-    such, part of the processing required
     ditional approaches are not enough         to operate the vehicle needs to take                                                   destrians are gonna be doing.”
     for a vehicle that is interacting with     place onboard, while model refine-
     other moving objects around it and         ments could be done on the cloud.
     their output needs to be fine-tuned.                                                                                              Anthony Levandowski,
                                                Recent advances in machine learning                                                    autonomous vehicle technology
     Some autonomous vehicles rely on           are focusing on how the huge amount
                                                                                                                                       pioneer, April 2019 [90]
     machine learning algorithms to not         of data generated by the sensors on-
     only perceive their environment but        board AVs can be efficiently processed
     also to act on that data to control        to reduce the computational cost,
     the car. Path planning can be taught       using concepts such as attention [88]
     to a CNN through imitation learning,       or core-sets.[89] In addition, advances
     in which the CNN tries to imitate the      in chip manufacturing and miniatur-
     behavior of a driver. In more advanced     ization are increasing the computing
     algorithms, DRL is used, where a           capacity that can be mounted on an
     reward is provided to the autonomous       autonomous vehicle. With advances
     system for driving in an acceptable        in networking protocols, cars might
     manner. Usually, these methods             be able to rely on low-latency net-
     are hybridized with more classical         work-based processing of data to aid
     methods of motion planning and             them in their autonomous operation.
     trajectory optimization to make sure
     that the paths are robust. In addition,
     manufacturers can include additional
     objectives, such as reducing fuel use,
     for the model to take into account as
     it tries to identify optimal paths.[87]

                                                                        Autonomous vehicles deploy algorithms to plan the vehi-
                                                                        cle’s own path, as well as estimate the path of other moving
                                                                        objects (in this case the system also estimates the path of
                                                                        the 2 red squares that represent bicyclists). Image: Waymo

42                                                                                                                                                                                         43
You can also read