RadioNet Workshop on Future Trends in Radio Astronomy Instrumentation
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RadioNet Workshop on
Future Trends in Radio
Astronomy Instrumentation
Monday 21 September 2020 - Tuesday 22 September 2020
Max Planck Institute for Radio Astronomy
Book of Abstracts
Here you can find all the abstracts of the sessions in our workshop. For technical and
administrative issues see ‘Welcome and organization’ where you can find some important advice
how to come through this workshop.
111RadioNet Workshop on Future Trends in Radio Astronomy Instru . . . / Book of Abstracts
Inhalt
Dial In ............................................................................................................................. 3
Welcome and technical issues ........................................................................................... 3
Director’s welcome address ............................................................................................... 3
SKA1 Observatory Developement Plan ............................................................................... 3
IRAM telescope instrumentation overview and future plans .................................................. 4
LOFAR2.0: extending LOFAR observational capabilities for the coming decade ...................... 4
The VLBA New Digital Architecture .................................................................................... 4
The Effelsberg Direct Digitizaion Project ............................................................................. 5
BRAND EVN Broadband Receiver - a technological chal- lenge ............................................. 5
Developing Digital Receiver for Radio Astronomy Receiver using RFSoC ................................ 5
Smart Ambient-Temperature Very Low Noise LNAs for Radio Astronomy Arrays..................... 6
Accelerating astronomy using Atomic COTS ....................................................................... 6
Bluering Prototype System Results ..................................................................................... 7
VLBI with a remote maser and a COTS formatter ................................................................ 7
A Q-band 19 pixel multifeed receiver for the Sardinia radio telescope..................................... 8
Latest calibration results from QUBIC: The Q&U Bolomet- ric Interferometer for Cosmology ... 8
Simulations of the Optical System of the LSPE‐STRIP Instrument ......................................... 8
Application of TES bolometers and KID cameras to pulsar observations ................................ 9
Solar power mirror arrays for radio astronomy - towards a test with the Juelich Solar Power
Tower .............................................................................................................................. 9
Managing hundreds of wideband receiving signals at the SRT .............................................. 9
A Compact Triple Band Receiver System working at K-, Q- and W-band for Medicina, Noto and
Sardinia Radio Tele- scopes ............................................................................................ 10
Science applications of multiband receivers and frequency-phase transfer ........................... 10
Design and Implementation of Remote RFI Monitoring System ............................................. 10
Efficient wide-area sky monitoring ................................................................................... 11
Development of an Optimized Real-Time Radio Transient Imager for LWA-SV ..................... 11
Earth-Orbit Aperture Synthesis ........................................................................................ 11
Open discussion, workshop summary, and closure ............................................................ 11
Page 2RadioNet Workshop on Future Trends in Radio Astronomy Instru . . . / Book of Abstracts
Registration / 0
Dial In
The zoom link including the password will be distributed shortly before the workshop by e-mail. We will
give you 30min to open your connection to the workshop so please use the time for connection and
testing. As we have more than 100 participants this could take some time. In case you have problems
please contact our moderator Zegeye Kidane under zkidane(at)mpifr.de.
Welcome / 19
Welcome and technical issues
Some technical/administrative issues will be explained: how to use zoom with screen sharing and the chat
function for questions, how the trivia evening is working, how we want to make a group photo.
Welcome / 20
Director’s welcome address
Corresponding Author(s): azensus@mpifr-bonn.mpg.de
Session 1: / 3
SKA1 Observatory Developement Plan
Mr. STRINGHETTI, Luca1
1
SKA Organisation
Corresponding Author(s): l.stringhetti@skatelescope.org
It is universally recognised that a well-funded and carefully targeted development programme is
essential to maintain the scientific competitiveness of any observatory. The purpose of the SKA
Observatory Development Programme (SODP) is to enhance the scientific productivity of the
Observatory by: adapting to changes in the scientific landscape and priorities, enabling new science,
restoring descoped functionality, improving output and reliability and reducing operational cost.
The SODP is divided into Projects, which deliver major improvements, and Studies, which are intended
to evaluate new ideas and bring them to an adequate Technology and Manufacturing Readiness Level
(TRL/MRL) to become potential projects. The process requires prioritisation of research and
development in the context of science and technology roadmaps. The present discussion is restricted to
SKA1 and concentrates on the initiation of the SODP and its evolution as the Observatory transitions from
the Construction phase into the operational phase. The talk will present the current plan for the SKA
observatory development program as part of the SKA Operation. It will present the organization of the
SKA1 roadmaps (science Roadmap and Technological Roadmap) how they are organized and how they
will work together to realize the SODP objectives. It will also show the current schedule and the
funding mechanism for the programme.
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Session 1: / 10
IRAM telescope instrumentation overview and future plans
Dr. RISACHER, christophe1
1
IRAM
Corresponding Author(s): risacher@iram.fr
IRAM operates two millimetre observatories on two sites: the NOEMA interferometer located in the
French Alps at 2500m altitude with currently 11 antennas of 15m diameter and the 30m telescope in
southern Spain, Pico Veleta (3000m). They observe in the 70-373 GHz frequency range. We’ll summarise
the current receivers status and performance, and present the plans for the near and far future. In
particular, we are starting an upgrade of the current NOEMA receivers to allow interferometric dual
frequency observations. On the longer term, new generation of SIS mixers will allow extending the RF and
IF bandwidths. Very large heterodyne array receivers are also under development, at 3 mm and 1.3
mm for the 30m Telescope.
Session 1: / 26
LOFAR2.0: extending LOFAR observational capabilities for the
coming decade
Dr. BOONSTRA, Albert-Jan1
1
ASTRON
Corresponding Author(s): boonstra@astron.nl
ASTRON operates the pan-European Low -Frequency Array (LOFAR), a unique instrument that will
complement phase one of the Square Kilometre Array (SKA), planned for construction in the coming
three to five years. After nearly a decade of scientific operations, LOFAR science output is still
ramping up. However, to keep the telescope at the forefront of science, a staged upgrade programme
LOFAR2.0 was set in motion. This programme includes upgrading LOFAR phased-array stations by
increasing the number of connected antennas, and by jointly observing the low-band and high-band
frequencies. This will greatly increase the sensitivity, especially at the lowest frequencies where
ionospheric effects are most severe. Simultaneous observations with both bands will allow to
calibrate out these effects at the low band by using the ionospheric calibration solutions at the high
band. The presentation will describe the new station architecture, show the first laboratory tests,
and will also highlight the new design methodology.
Session 1: / 5
The VLBA New Digital Architecture
Dr. BRISKEN, Walter1
1
National Radio Astronomy Observatory
Corresponding Author(s): wbrisken@nrao.edu
A new digital back-end architecture for the Very Long Baseline Array (VLBA) is being developed at NRAO.
The system will consist of several main components that are interconnected through a 100 Gbps
Ethernet switch. A pair of dual-channel IF samplers will be placed in the VLBA receiver cabin,
producing four VDIF streams at 2048 Gsps and with greater than 8 bits per sample quanitzation. These
“digital IFs” are to be injected into the 100 Gbps switch as VDIF packets over multicast UDP, allowing
one or more “consumer” modules to perform further processing. For the VLBI use case, a module that
channelizes and requantizes the data will feed Mark6 recorders. the architecture will allow other
commensal uses of the digital IF streams such as transient searching, pulsar timing, or spectroscopy. In
this talk, I will discuss the overall system architecture, the status of the project, and the motivations
that led to this particular design choice.
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Session 2 / 24
The Effelsberg Direct Digitizaion Project
Dr. WINCHEN, Tobias 1, BANSOD, Amit 1, BEHREND, Jan 1, Dr. BARR, Ewan 1
, Mr. ESSER, Niclas
Alexander 1, Ms. SATHYANARAYANAN, Sakthi Priya 1, WIECHING, Gundolf 1
WU, Jason 1
1
Max Planck Institute for Radio Astronomy
Corresponding Author(s): twinchen@mpifr-bonn.mpg.de
Recent developments in high-speed networking and PCIe-mounted accelerator cards have
made possible new backend designs that provide vastly improved flexibility and capability in
signal processing for radio astronomy. While direct digitization close to the receiver improves
the quality of the physical signal by reducing analog transmission and filtering losses, it also
enables the building of a backend based on commercial-off-the-shelf (COTS) hardware that is
able to exploit modern cloud computing paradigms. In the Effelsberg Direct Digitization (EDD)
project we are developing a versatile backend that takes advantage of these benefits. The EDD
backend orchestrates data processing on COTS computing systems hosting GPUs as well as
FPGA that can be rapidly and easily adapted to a wide range of observing use cases, e.g.
spectroscopy, polarimetry, pulsar timing, etc. The highly modular system uses a unified
interface for the control of its subsystems. This interface abstracts the telescope into well
defined components which allows for a universal design suitable for deployment at any radio
observatory only minimal customisation.
Session 2 / 15
BRAND EVN Broadband Receiver - a technological chal- lenge
TUCCARI, GinoNone
Corresponding Author(s): tuccari@mpifr-bonn.mpg.de
The BRAND wideband receiver is being developed with support from the European Union’s Horizon
2020 research and innovation programme as a part of RadioNet. The project represents a big technological
challenge in the entire signal chain from the feed section to the digital processing. Its continuous frequency
range from 1.5 GHz to 15 GHz makes it a scientifically extremely interesting development for the EVN
network and radio astronomy in general. It also covers the VGOS frequencies and even extends them
to lower and higher frequencies. It will allow to retrofit traditional prime focus antennas to become
compatible with VGOS antennas in terms of frequency coverage, with a much greater output data rate.
The status of the project is reported with the goals achieved and the items still under way.
Session 2: / 8
Developing Digital Receiver for Radio Astronomy Receiver using
RFSoC
Dr. LIU, Chao1
1
Oxford University
Corresponding Author(s): chao.liu@physics.ox.ac.uk
The ultra-wideband redshift search receiver (RSR) on Large Millimetre Telescope (LMT), which covers 73
- 110.5 GHz simultaneously, has been built about 10 years ago. Due to the limits in the speed,
performance and cost of the high speed sampler when the receiver was designed, the receiver was
implemented using analog autocorrelator. As the price-performance rate in digital technologies is
constantly improving, replacing the analog RSR receiver by a digital one becomes feasible. The digital
system could offer higher frequency resolution and more system flexibility for more advanced science cases.
This project was aimed to design and implement digital backend system for RSR. The RFSoC from Xilinx
caught the attention of radio astronomy community when first released. RFSoC device has been
selected as a core platform for the RSR receiver, as it offer 8x4G ADCs, large amount of programmable
logic resources and powerful processor with multiple cores. Therefore, the RFSoC can integrate signal
sampling, data processing and transmission and control functions in a single IC, which will be beneficial
in both system design and costing perspectives. The talk will be focused on the digital backend system
built for RSR and general radio astronomy receivers based on the RFSoC. The system at the present
stage is fully functional as a spectrometer and can be extended in any shape base on system requirement of
different telescopes and science cases. The experimental ADC characterization demonstrates around 80
dB Spurious Free Dynamic Range (SFDR) over the spectrum from DC to 2.048 GHz. The evaluation
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results of the RFSoC based spectrometer performs with high level of stability and dynamic range with
hundreds of seconds’ real-time integration time. The results give us solid confidence in using RFSoC
for radio astronomy receivers. It is a critical milestone of the RSR receiver project and we can carry on
by just scaling the system up. The RFSoC based receiver modules will be extend to CBASS, Goonhilly
GHY3 and other receiver platforms under development in Oxford. The system is not only suitable for high
bandwidth signal but also hugely beneficial for systems with high channel counts, such as SKA, ATA
and other interferometry radio astronomy telescopes. The RFSoC data converters can digitize as many
as 16 channels simultaneously, the programmable logic can handle the channelization and
beamforming and the control and communication can be managed by the applications on ARM
processors. It can largely save the system cost and development effort in both hardware and software
perspectives.
Session 2 / 27
Smart Ambient-Temperature Very Low Noise LNAs for Radio
Astronomy Arrays
Dr. WEINREB, Sander1
1
Caltech
Corresponding Author(s): sweinreb@caltech.edu
Most radio telescopes can have greatly expended survey speed and imaging capability by utilizing
multiple receivers either as feed clusters, phased-array feeds, or a larger number of individual
antennas. The number of receivers is often limited by the cost of the cryogenic cooling required for
sensitivity at frequencies > 1 GHz. This paper will describe a new class of LNAs for the low
microwave range that operate at ambient temperature and are “smart” in that they include
functions such as noise calibration, tuning, switching, and monitoring within the LNA package. In
addition, the LNAs are powered and controlled by just one wire, the output coaxial cable. A first
generation of this new class of LNAs has been developed for detection and location of fast radio
bursts (FRBs) in a 110 x 5m array at the Caltech Radio Observatory in Owens Valley, CA. These
DSA110 LNAs have noise temperature in the 7 to 9 K range to realize system noise temperatures in
the 22 to 25 K range in the frequency band of 1.28 to 1.53 GHz. Over 40 of the LNAs have now been
completed and have internal, temperature-compensated, noise calibration signals so they can be
directly attached to the dual -linear polarized feed without the directional coupler usually required
for calibration. Further development of this LNA for a proposed DSA2000 array is in process and
will include internal cooling to -40C of the InP HEMT input transistor utilizing a Peltier micro-
cooler. This cooling is motivated by the large decrease in noise temperature with physical
temperature measured for the DSA110 LNAs; the noise decreases by approximately a factor of two
upon cooling from +40C to -40C, a much greater factor than the change in absolute temperature,
313K to 233K. This change is believed to be due to a large decrease in the transistor hot-electron
noise, an effect not noted in previous studies and a subject of a theoretical study at Caltech.
Session 3 / 6
Accelerating astronomy using Atomic COTS
Dr. HAMPSON, Grant1
1
CSIRO
Corresponding Author(s): grant.hampson@csiro.au
In the 20th century high end correlators were built with ASICs (VLA, Westerbork, Australia
Telescope). As we entered the 21st century FPGAs came to the fore (eVLA, CABB, etc.) but due to the
huge data flows they needed massive dedicated data transport systems. The CASPER group followed a
different path and used network switches for data transport but this imposed a significant extra cost
and for large systems such as MeerKAT with considerable effort and interaction with the switch
vendor to get the system to work. The last 5 years has seen the appearance of a new generation of
Ethernet switches (In-Network Processors) where the data plane is fully programmable using languages
such as P4 and OpenFlow. These languages not only allow precise routing of packets based on metadata
within the Ethernet packets but also open the door to a precise monitoring of the data flow. Thus, the
designer now has the control available with older designs but without the complexity and with more
advanced features.
The second revolution was the combination of FPGAs and High Bandwidth (attached) Memory (HBM).
HBM memory has an I/0 bandwidth that is more than 30 times that of a 100GbE link. This allows the
full data to be buffered to memory multiple times. Each stage of processing can now operate
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independently of any other, effectively independent asynchronous subroutines (whereas all early
correlator designs were synchronous). The multiple “subroutines” can now implement end-to-end
processing. These FPGAs are now available as COTS hardware ready to plug into a standard server and
have 100GbE ports that can connect to the In-Network Processor. The combination of these two
technology advances allows a new approach to radio astronomy correlators and beamformers - what we
have called “Atomic COTS”. This is a design that uses COTS In-Network Processors to route data to
COTS FPGA cards such that each card receives part of the total bandwidth for all receiving elements.
The FPGA then completes all processing to implement a correlator or beamformer independent of any
other FPGA (an Atomic operation).
The resulting astronomy data products can be routed back through the In-Network Processors to the next
stage of processing such as imaging with visibilities and searches for FRBs on tied array beams. An Atomic
COTS architecture will enable astronomy backends to upgrade and deploy incrementally.
Session 3 / 7
Bluering Prototype System Results
Dr. HAMPSON, Grant1
1
CSIRO
Corresponding Author(s): grant.hampson@csiro.au
Bluering is the CSIRO name given to a new generation of radio astronomy array receivers based on Xilinx’s
Radio Frequency System on Chip (RFSOC) technology. Bluering was initially designed for low frequency
radio astronomy applications (such as the MWA telescope), but has grown to be a receiver also capable of
L-band radio astronomy (such as Phased Array Feeds). Bluering is not only an array receiver; the spare
FPGA resources can be used to form multiple wideband beams, compute the array covariance
matrix, RFI mitigation, and even pulsar timing.
To enable many types of astronomy receiver applications an RF daughter board, called Taipan, can be
customised to have coaxial and fibre inputs. Available to each Taipan is a tuneable LO signal (which can
double the number of RF inputs for some frequencies), attenuator control bits as well as a calibration
signal. With all these features it is possible to customise the Taipan to most astronomy applications.
CSIRO has developed a prototype Bluering system based around the 16 input 2GSPS 12-bit ADC
version of the RFSOC. This paper presents some of the design details, including liquid cooling, RFI
shielding, optical timing, embedded control system, as well as signal processing and communications
firmware. Prototyping results are also presented - in particular RFI shielding, power, weight, SNR, etc.
will be shown. Following the development and testing of this initial version CSIRO is planning on
building a second version (without some of the bugs!) and aims to improve the general performance of
the system.
Session 3 / 17
VLBI with a remote maser and a COTS formatter
Mr. BOVEN, Paul1
1
JIVE
Corresponding Author(s): boven@jive.eu
The Hydrogen maser is required equipment for any VLBI station, and so is a formatter such as a
DBBC(1,2 or 3) or DBE. Together, these ensure that the received spectrum gets digitized, timestamped
with sufficient stability, and provided with headers to allow playback at a correlator. These necessities
however don’t come cheap.
White Rabbit is an open standard for time and frequency distribution over fiber. It was originally intended
to synchronize and control the experiments at the LHC, but we show that it is possible to extend its reach
and frequency stability in such a way that it can be used to transport a reference clock for VLBI.
GNU Radio is a “free and open-source software development toolkit that provides signal processing blocks to
implement software defined radios”. Using this software, I’ve designed a VLBI receiver and formatter
using an off the shelf software-defined radio. It generates standard compliant VDIF data, which can be
processed by the EVN SFXC correlator, and many others. Our first experiments were not able to be
processed in real-time and only provided two subbands, but work is ongoing to develop this into a 1024
Mb/s capable VLBI formatter.
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Using these two methods, and the H-maser at the WSRT, we have successfully demonstrated VLBI
fringes between the historical 25m Dwingeloo telescope and many EVN stations.
Session 3 / 1
A Q-band 19 pixel multifeed receiver for the Sardinia radio
telescope
Dr. ORFEI, Alessandro1
1
INAF-IRA
Corresponding Author(s): a.orfei@ira.inaf.it
A 19 feed 33-50GHz receiver under construction for the SRT antenna will be presented. The key modules
will be described as well as their measurements in the laboratory.
Session 4 / 12
Latest calibration results from QUBIC: The Q&U Bolomet- ric
Interferometer for Cosmology
MOUSSET, Louise1
1
obsparis
Corresponding Author(s): jcasado@mpifr-bonn.mpg.de
QUBIC is an experiment dedicated to the measurement of the B-mode polarization from the Cosmic
Microwave Background (CMB), using a novel technology: Bolometric Interferometry. The instrument will
have 2 focal planes at 150 GHz and 220 GHz. Thanks to its unique spectroimaging capabilities, QUBIC will
also be a powerful instrument to constrain foreground contamination (thermal galaxy dust emission,
synchrotron emission, ...). The technical demonstrator has been tested and the concept of this new
instrument has been validated. In this talk, I will 1rst explain the instrument architecture, focussing on
the optical design. Some of the calibration results will be presented, showing that we actually have a
working bolometric interferometer. The unique design of QUBIC brings new possibilities to CMB
polarization mapping
Session 4 / 22
Simulations of the Optical System of the LSPE‐STRIP Instrument
Ms. REALINI, Sabrina1
1
Università degli Studi di Milano
Corresponding Author(s): sabrina.realini@unimi.it
We present the analysis of the optical system of the STRIP instrument, the ground-based telescope
of the Large Scale Polarization (LSPE) experiment, which aims at polarization measurements of the
Cosmic Microwave Background on large angular scales. STRIP will observe the polarized emission
from the "Observatorio del Teide" in Tenerife, starting in late 2021. The instrument consists of an
array of forty-nine coherent polarimeters at 43 GHz (Q-band), coupled to a 1.5 m fully rotating
crossed-Dragone telescope. An additional frequency channel with six-elements at 95 GHz (W-band)
will be exploited as an atmospheric monitor. We modelled and characterized the STRIP optics by
means of electromagnetic simulations. The model includes the two nominal reflectors, forty-nine Q-
band feedhorns, six W-band feedhorns, and the shielding structures. We present the results of the
optical simulations of both main beam and sidelobes, including the effects of the infrared filters and
the dielectric window of the cryostat. An analysis of the mirrors imperfections and deformations
completes our understanding of the LSPE-STRIP optical response in its real configuration.
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Session 4 / 18
Application of TES bolometers and KID cameras to pulsar
observations
Dr. TORNE, Pablo1
1
Instituto de Radioastronomia Milimetrica (IRAM)
Corresponding Author(s): torne@iram.es
Pulsar studies are generally carried out at centimetre wavelengths and high-energies (X-ray, Gamma-
ray), where pulsars are brighter and the available instrumentation is well adapted to fast time-domain
science. In the last years, pulsar astronomy in the millimetre band has intensified, supported mainly by
large-bandwidth instrumentation with fast-sampling capabilities at the IRAM 30-m telescope. However,
receiver and backend combinations suitable for pulsar observations at (sub)millimetre facilities are
rare. In this contribution, we will discuss a novel application of continuum cameras to pulsar
astronomy in the (sub)millimetre range, which offers a new possibility to enable pulsar observations
with high sensitivity at observatories where these type of receivers are (or will be) available. This
promises to extend the spectral window in which pulsars can be studied, often with minimal or no
extra modifications to the original hardware. Two proof-of-concept experiments will be presented, showing
detections of a radio magnetar with the NIKA2 KID camera on the IRAM 30-m Telescope, and the
SCUBA2 TES bolometer on the James Clerk Maxwell Telescope.
Session 4 / 9
Solar power mirror arrays for radio astronomy - towards a test
with the Juelich Solar Power Tower
Author(s): ROY, AlanNone
Co-author(s): WUCKNITZ, Olaf ; Dr. CAMARA MAYORGA, Ivan 1
1
MPIfR
Corresponding Author(s): aroy@mpifr-bonn.mpg.de
We have presented the idea at past meetings to use the mirror arrays of concentrating solar power stations
as vast collecting areas for high-sensitivity radio astronomy. Since the signals do not combine
coherently they will produce an extended speckle pattern over the focal region that requires a large
phased array feed to collect and combine in-phase. The 4000 element EMBRACE array developed under
the RadioNet SKADS project is such array feed and might conceivably be re-purposed for this
application. We will give an update on the idea and the plans for a proof-of-concept experiment on
the Juelich experimental solar array. For simplicity these start with a two-pixel receiver before scaling
up.
Session 5 / 2
Managing hundreds of wideband receiving signals at the SRT
Dr. ORFEI, Alessandro1
1
INAF-IRA
Corresponding Author(s): a.orfei@ira.inaf.it
The completion of the receiver suite up to 116 GHz at the Sardinia radio telescope asks for a completely
new infrastructure for routing hundreds of large bandwidth signals to several back-ends of different type. In
this talk I’ll describe how these signals is thought to be handled as well as the status of the work in
progress.
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Session 5 / 11
A Compact Triple Band Receiver System working at K-, Q- and
W-band for Medicina, Noto and Sardinia Radio Tele- scopes
Dr. BOLLI, Pietro1
1
INAF
Corresponding Author(s): jcasado@mpifr-bonn.mpg.de
A Compact Triple Band Receiver System working at K-, Q- and W-band for Medicina, Noto and Sardinia
Radio Telescopes
Pietro Bolli (Italian National Institute for Astrophysics), Seog-Tae Han (Korea Astronomy and Space
Science Institute), Jihoon Choi (Korea Astronomy and Space Science Institute) and Alessandro Orfei
(Italian National Institute for Astrophysics)
A compact triple band receiver system is under development by a mutual collaboration between
INAF, Italy and KASI, Korea. Three receivers will be fabricated and installed on the 64 m Sardinia
radio telescope, 32 m Noto and Medicina radio telescopes respectively. Each receiver enables
simultaneous observations in the three frequency intervals: K-band (18–26 GHz/8 GHz IF bandwidth), Q-
band (34–50 GHz/16 GHz IF bandwidth) and W-band (85–116GHz/32 GHz IF bandwidth). An integrated
quasi-optical circuit plus a compact triple-band receiver located in a single cryostat is chosen in order to
circumvent difficulties in installation and beam alignment. A frequency-independent quasi-optical circuit
for each band is adopted to obtain constant aperture efficiency as a function of the observed frequencies.
The simulation results show that total aperture efficiency of each recommended frequency band is
maintained almost constant within 1%. We present the design details of the compact wideband quasi-optical
circuit and the properties of the triple-band receiver optimized for simultaneous multi-frequency
observations. It is expected that it will be dedicated to conduct millimeter wave VLBI and Sun
observations.
Session 5 / 25
Science applications of multiband receivers and frequency-
phase transfer
LOBANOV, Andrei 1
1
MPIfR
Corresponding Author(s): alobanov@mpifr-bonn.mpg.de
The technological developments pioneered at the Korean VLBI Network for designing and
implementing simultaneous multfiband (SMB) receivers paved the way to extending phase
calibration and phase referencing techniques to the frequency space. Numerous advantages of
this extension have been convincingly demonstrated at the KVN, and the time is now right to
explore them on a larger scale. This would enable reaching an astrometric accuracy of ~10
microarcseconds, performing relative astrometric measurements at multiple frequencies, and
increasing the dynamic range of mm-VLBI observations by factors of 20-50. A possible
extension of the frequency-phase transfer (FPT) to 230 GHz is likely to bring a critically needed
improvement of the quality of EHT imaging. Scientific potentials of implementing the SMB for
mm- and sumnn-VLBI on a global scale will be discussed in this presentation
Session 6 /4
Design and Implementation of Remote RFI Monitoring System
NSOR, Joseph A. K1
1
Ghana Space Science & Technology Inst.
Corresponding Author(s): jcasado@mpifr-bonn.mpg.de
Design and Implementation of Remote RFI Monitoring System
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Session 6 / 14
Efficient wide-area sky monitoring
WUCKNITZ, Olaf1
1
MPIfR
Corresponding Author(s): wucknitz@mpifr-bonn.mpg.de
The enigmatic Fast Radio Bursts (FRBs) are motivating new instruments to monitor large areas of
the sky with high time resolution. With a field of view of about 200 square degrees, CHIME is
currently finding several per day. Gravitationally lensed FRBs could be used as a new cosmological
probe, but this requires the continuous monitoring of even wider areas. Regular antenna arrays can be
combined with extremely efficient Fast-Fourier-Transform beamformers to map good fractions of the sky
with full time resolution. We discuss some options, including the (mis-)use of existing phased-array-
feed receivers as aperture arrays.
Session 6 / 16
Development of an Optimized Real-Time Radio Transient
Imager for LWA-SV
Dr. KRISHNAN, Hariharan1
1
Arizona State University
Corresponding Author(s): vasanthikrishhari@gmail.com
In this paper, we describe our efforts towards the development of a real-time radio imaging correlator
for the Long-Wavelength Array station in Sevilleta, New Mexico. We briefly discuss the direct-imaging
algorithm and present the architecture of the GPU implementation. We describe the code-level
modifications carried out to some of the modules in the algorithm that improves GPU-memory
management and highlight the performance improvements achieved through it. We emphasize our
ongoing efforts in tuning the overall run-time duration of the correlator which in turn is expected to
increase the operating bandwidth in order to address the demands of wide-band capability for radio
transient science.
Session 6 / 13
Earth-Orbit Aperture Synthesis
ROY, AlanNone
Corresponding Author(s): aroy@mpifr-bonn.mpg.de
I investigate the idea that VLBI might be done between one antenna and itself as it moves along the
Earth’s orbit, provided the bandwidth is sufficiently small that the coherence time is longer than the time
needed for the antenna to sweep out the baseline. Such a technique offers the tantalizing prospect of
synthesizing space-VLBI-like baselines without needing a satellite, or the ability to fill in missing short
baselines in EVN. However the initial result from a numerical model is that it does not work, at least for
uniform linear motion, for an interesting reason.
Summary / 21
Open discussion, workshop summary, and closure
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