Cheia Antenna Retrofit Phase II - RADAR for space objects detection Col. (r) Dr. Eng. Liviu Ionescu Dr. Eng. Alexandru Rusu Program Manager Dan ...
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Cheia Antenna Retrofit Phase II RADAR for space objects detection Col. (r) Dr. Eng. Liviu Ionescu Dr. Eng. Alexandru Rusu Program Manager Dan Istriteanu 16.03.2021 Stardust-R Network Training School III
Contents • About Telespazio • RARTEL’s background • Cheia antenna retrofit project Consortium Subcontractors About the project and steps already done Advantages of Cheia antennas retrofitting System scope and requirements Space objects detection methods RADAR General diagram RADAR Physical implementations Radar detection capabilities Radar constraints LFM CW Probing signal Amount of trackable objects Conclusions
About Telespazio: the Space Alliance 14,0 B€ revenues 62.000 employees approx. 13,0 B€ revenues over 47.000 employees Space Alliance presence in the Space Value Chain Systems Development Operations Management Systems Application Launch Satellite Ground Mission Satellite Management Control / Networks & Applications Equipment Definition Production (on behalf of Mission Platforms & Services Production customer) Control 3 Copyright RARTEL 2021 All rights reserved © 2016, Telespazio
International Presence Telespazio e-GEOS Telespazio France Telespazio VEGA Deutschland GAFAG spaceopal Telespazio VEGA United Kingdom Telespazio Ibérica Rartel Telespazio Brasil Telespazio Argentina 4 Copyright RARTEL 2021
Italian Space Centres LARIO SPACE CENTRE FUCINO SPACE CENTRE MATERA SPACE CENTRE SCANZANO SPACE CENTRE 5 Copyright RARTEL 2021
International Space Centres ROMANIA CHEIA BRASIL RIO DE JANEIRO PORTO ALEGRE ITABORAÍ ARGENTINA BUENOS AIRES 6 Copyright RARTEL 2021
Telespazio in Romania: RARTEL SA 62 % 38 % 7 Copyright RARTEL 2021
Participation of RARTEL in ESA Projects Milestones: 22.12.2011 Romania become ESA member 2012-2021 – More than 20 projects with ESA (prime and sub) Copyright RARTEL 2021
Relevant projects of RARTEL (1) Space Situation Awareness (SSA) for Romania (Romanian Industry Incentive Scheme) define infrastructure and existing equipment in Romania and their applicability within the ESA SSA program give guidelines for future involvement of the Romanian institutions and space industry through ESA-SSA programs (Ended 2015) Copyright RARTEL 2021
Relevant projects of RARTEL (2) Cheia antenna retrofit (RIIS) + Cheia antenna retrofit phase 1 possible reutilization of the 32 meters antennas presently available at the Cheia Satellite Ground Station, in the context of SSA programme Preliminary design review (ended 2018). Copyright RARTEL 2021
Cheia antenna retrofit project Idea: 2 existing 32-meter C-band antennas located in the Cheia Space Center (Romania, Prahova County), currently unused and with very limited prospects for re-use for telecommunication services, can be used as radar for detecting and tracking space objects. Scope: design the radar by minimizing the changes to be made in order to achieve a good compromise between costs and radar surveillance / tracking capabilities Another goal: Creating an infrastructure that could allow Romania to join the European Consortium for Space Surveillance and Tracking (SST) Copyright RARTEL 2021
EUSST consortium Romania was admitted in EUSST consortium in 2018 Copyright RARTEL 2021
Cheia antenna retrofit project consortium RARTEL S.A.- BUCHAREST, ROMANIA Silicon Acuity S.R.L.- BUCHAREST, ROMANIA AD HOC Ad Hoc Telecom Solutions S.R.L.- BUCHAREST, TELECOM ROMANIA SOLUTIONS Astronomical Institute of Romanian Academy IAAR Project financed by Copyright RARTEL 2021
From where we started Two 32meter antennas In service from 1977 and 1979 Produced by NEC Japan Purpose: Telecommunication services in C-band No longer in service (In conservation mode) Copyright RARTEL 2021
System scope • The main scope of this radar system shall be to detect and track LEO objects (above a defined size and up to an altitude of 200 – 2000 km). • The sensor shall contribute to refine: the ESA space debris environment model containing physical and orbital information about LEO space debris, to refine a future European Master Catalogue for Space debris. • Other uses can be based on national and / or international requests made by entities and institutions acting in the SST domain. Copyright RARTEL 2021
System requirements • The system shall provide object tracking capabilities; • The following accuracy shall be assumed for the input orbital information: - 2 km along-track error (corresponding to ~0.3s TOV at 500 Km height) - 100 m cross-track (corresponding to ~0.01° at 500 Km height) • For each detected object the radar shall provide the following time-tagged parameters: - Azimuth - Elevation - Range - Doppler - Received signal strength • Elevation tracking range 0 to 90°; • Azimuth tracking range 10° to 350° ; • Antenna speed 0.3°/s (positioning and slewing) 0.6°/s, goal 1°/s ; • 1-σ Range accuracy
Space objects detection methods Optical: • Uses telescopes • Optical visibility dependent • Cannot measure range directly Monochromatic light: • Uses lasers (laser rangers) • Optical visibility dependent • Cannot measure range directly except for some special applications (LiDAR) Radio waves: • Uses radars • Not dependent on optical visibility • Can measure range and Doppler speed • Lower angular accuracy than telescopes and lasers Copyright RARTEL 2021 17
RADAR Physical implementations Monostatic: • Same antenna for Tx and Rx. • Needs a diplexer to separate Tx and Rx paths. The Tx –Rx separation is limited. • Can be used only if very high power is radiated (100 kW to MW) Quasi Monostatic: • Two different antennas in close locations (up to 1km). • Does not need a diplexer but needs low coupling between antennas • Can be used with low radiated power if the coupling is low enough Bistatic: • Two different antennas in remote locations. • Inherent low antenna coupling • Requires very good synchronization between antenna sites (dedicated link) Copyright RARTEL 2021 18
RADAR General diagram Copyright RARTEL 2021 19
Radar detection capabilities • Radar general equation 4 3 ∙ ∙ ∙ ∙ ∙ ∙ 2 2 = ∙ ∙ ∙ ∙ ∙ 2 • Parabolic Antenna gain 2 = 0,6 ∙ • Parabolic antenna noise temperature = 20 ÷ 60 • Spherical reference target RCS 2 ℎ ℎ ℎ = ∙ (optical region > 5) 4 Copyright RARTEL 2021 20
ESA requirements for LEOs Copyright RARTEL 2021 21
Radar transmitter constraints • To preserve the detection capabilities, the transmitted power has to be increased if the antenna D/l ratio is decreased • A value of ∙ ∙ = 34 + 2 ∗ 63,5 = 161 allows fulfilling the ESA requirements if the receiver is capable of producing a = 13,2 ( = 0,9 ; = 10−6 ) for a C-band input signal level of = −148 • Reducing the transmitted signal wavelength allows improving the detection capabilities but increases the cost and reduces the power amplifier thermal efficiency • To use SSPA as power amplifier, CW signal has to be transmitted. Pulsing a SSPA at the current technological level will reduce its reliability. Copyright RARTEL 2021 22
Radar receiver constraints • To increase the receiver sensitivity, the smallest bandwidth possible has to be chosen • A value of = 20 allows fulfilling the requirement of producing a = 13,2 ( = 0,9 ; = 10−6 ) for a C-band input signal level of = −148 and a Rx-Tx antenna coupling of -115dB • For Rx-Tx antenna coupling exceeding -115dB, supplemental in- band noise reduction techniques have to be used, the bandwidth has to be reduced or the transmitter phase noise has to be reduced. • The receiver constraints require strong analog and digital signal processing Copyright RARTEL 2021 23
Radar receiver constraints (cont’d) • To reduce the receiver noise factor, , a very low noise LNA has to be used. • To reduce the receiver noise factor, , very low phase noise and spurious local oscillators have to be used • To accommodate the large variation of the reflected signal the receiver must provide a large dynamic range of at least 60 dB. Copyright RARTEL 2021 24
Probing signal constraints • To concentrate its energy in a bandwidth as low as 20 Hz, the probing signal has to be either continuous (CW) or very long pulses (>50ms). • To provide acceptable Range and Doppler resolution and accuracy, the probing signal has to be modulated, the most efficient modulation being the Linear Frequency Modulation (LFM) • LFM CW probing signals offer significant receiving and processing advantages. Copyright RARTEL 2021 25
LFM CW Probing Signal • Time delays are transformed in frequency delays using the beat process • All processing is performed in the frequency domain Copyright RARTEL 2021 26
Amount of trackable objects CW (PROOF 2009 simulations) Copyright RARTEL 2021 17.03.2021
Size of Trackable objects CW Conditions H (km) RCSmin (m2) Dobiect (cm) Rslant(km) e (°) 200,00 9,72E-04 1,8 584,76 20 300,00 4,92E-03 9 877,14 20 400,00 3,41E-03 8 800,00 30 500,00 8,32E-03 12 1.000,00 30 600,00 6,31E-03 11 933,43 40 700,00 1,17E-02 14 1.089,01 40 800,00 2,00E-02 16 1.244,58 40 900,00 1,58E-02 15 1.174,87 50 1.000,00 2,42E-02 18 1.305,41 50 1.100,00 2,16E-02 17 1.270,17 60 1.200,00 3,07E-02 19 1.385,64 60 1.400,00 3,40E-02 22 1.421,60 80 1.600,00 5,79E-02 26 1.624,68 80 1.800,00 9,28E-02 35 1.827,77 80 2.000,00 1,41E-01 44 2.030,85 80 Copyright RARTEL 2021 17.03.2021
Conclusions- Advantages of Cheia antennas retrofitting The presence of 2 identical 32 meters antennas in the same site, provides a versatility uncommon to the majority of sites having only one antenna The most Eastern location in the EU increase the window of visibility of a space object increase the detection probability increase the accuracy of orbit determination detection of additional satellites (for instance on GEO) which cannot be detected from the west side of Europe the radar sensor can certainly contribute to debris detection and tracking of large number of small objects to high altitude Radar design: Quasi-monostatic, for tracking LEO objects Low transmission power Continuous Wave signal Uses supplementary noise reduction techniques, due to antenna coupling Copyright RARTEL 2021
Thank you! Questions? https://conference.sdo.esoc.esa.int/proceedings/neosst1/paper/41 5/NEOSST1-paper415.pdf www.rartel.ro Alexandru Rusu alexandru.rusu@rartel.ro Copyright RARTEL 2021 30
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