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/ i i/ i iSEOSAR/PAZ SAR Mission: PSEOSAR/PAZ SAR Mission: PS OS / S ss oS OS / S ss oA Zurita A Solana and thA. Zurita, A. Solana and th
(1) all authors are with EADS CASA E( ) all authors are with EADS CASA E
1 I t d ti1. Introduction
SEOSAR/PAZ is the first Spanish high resolution X Band Synthetic ApertureSEOSAR/PAZ is the first Spanish high resolution X‐Band Synthetic ApertureRadar. The entire system is being developed under control and supervision ofRadar. The entire system is being developed under control and supervision ofHisdesat, who is also responsible for satellite operation and data exploitation.EADS CASA Espacio is the Satellite prime contractor company leading a widei d t i l ti hil INTA i ibl f th G d S tindustrial consortium, while INTA is responsible for the Ground Segment.
System Parameters
Lifetime 5.5 years
Orbit 514 km, polar dawn‐dusk sunsynchronous
Revisit time 1 day
Imaging 420 s (max.), 3 min (avgerage) per orbit
Modes Stripmap, Scansar, Spotlight (single, dual, quad)
SAR antenna 12 active panels (0.7 x 4.8 m each)
Weight 1350 kg
Frequency 9.65 GHz (300 MHz bandwidth)
Downlink 300 Mbps X‐Band (encrypted)
Table 1‐1 System Parameters
2 Panel Design2. Panel Design
Instrument panel consists of:Instrument panel consists of: 32 Antenna Subarrays (H&V) 32 Transmit‐Receive Modules (TRM) l b k ( ) 1 Panel Distribution Network (1:32) 1 Panel Calibration Network (1:32) 1 Panel Calibration Network (1:32) 1 Panel Supply Unit 1 Panel Supply Unit 1 Panel Control Unit
Antenna SubarrayFigure 2 1 Panel functional architecture
Each subarray contains 16 circular patches
Figure 2‐1 Panel functional architecture
Each subarray contains 16 circular patchesspaced 0.7 λ x 0.8 λ and fed via a multilayerp ystripline Beam Forming Network (H&V pol.).Measured losses achieved are < 1dB.
TR Modules
Figure 2‐2 Subarray in anechoic chamber
TRM performs the following functions: P lifi i d h Power amplification and phaseadjustment the TX signaladjustment the TX signal Amplification and phase adjustmentp p jof RX echo signals TX Power>37dBm Switching between H and V C li RX d TX i l f
RX Gain>28dBN i Fi <4 3 dB Coupling RX and TX signals for
calibration purposes
Noise Fig.<4.3 dB
Figure 2 3 TR Module
Panel Distribution/Calibration Networks
calibration purposes Figure 2‐3 TR Module
Panel Distribution/Calibration Networks Stripline Wilkinson dual power dividers 1:16 and 1:2 (double stacked) Stripline Wilkinson dual power dividers 1:16 and 1:2 (double‐stacked) Parallel feeding to minimize amplitude/phase errors Parallel feeding to minimize amplitude/phase errors
Figure 2 4 1:16 dual power divider
Panel Control Unit
Figure 2‐4 1:16 dual power dividerFigure 2‐5 PAZ panel model
Panel Control Unit Control of panel 32 TRM (phase & amplitude) datatake beam configurations Control of panel 32 TRM (phase & amplitude) datatake beam configurations TRM compensation: temperature, path offsets, biasing and parasitic effectsp p , p , g p
Panel Supply Unit Generation of 32 TRM secondary voltages
3 Panel Qualification3. Panel Qualification
Figure 3‐1 Qualification test campaign
Physical measurements: mass centre of gravity (z axis)
Figure 3 1 Qualification test campaign
Physical measurements: mass, centre of gravity (z‐axis) RF pre‐environmental test: subarrays amplitude/phase offsets, antennap y p /p ,model first validation Vibration: sine and random vibration (3 axis) Th l B l /Th l V Q lifi ti f th l t l t Thermal Balance/Thermal Vacuum: Qualification of thermal control systemand evaluation of electrical and functional performancesand evaluation of electrical and functional performances RF post‐environmental: Embedded subarray beam patterns verificationp y p
ESA E h Ob i S S h l 2010 ESRIN A 2010ESA Earth Observation Summer School 2010, ESRIN, August 2010
l i d fl i d fPanel Design and PerformancePanel Design and Performancea e es g a d e o a cea e es g a d e o a cehe PAZ Team (1)he PAZ Team (1)
SPACIO Madrid SpainSPACIO, Madrid, Spain
4 Instrument Performance4. Instrument Performance
Antenna ModelAntenna ModelAn accurate knowledge of SAR radiation patterns is needed for precise on‐An accurate knowledge of SAR radiation patterns is needed for precise onground image processing and data products calibration. End‐to‐endg g p g pcalibration shall take minimum operation time minimizing performancedegradations and long re‐calibration periods.
Figure 4‐1 Panel functional architecture
Validation & Verificationg
Each performance parameter is verified by review of design, analysis or test ofa set of contributions. These contributions are addressed in a first
i i P l lifi i l lapproximation at Panel qualification level.Stripmap‐Single Performance RequirementsStripmap‐Single Performance Requirements
Parameter Value First results
Polarization HH, VV
ll f l ° ° Full performance angle range 20° ‐ 45°
Data collection angle range 15° ‐ 45° Data collection angle range 15 45
Azimuth resolution ≤ 3m
Range resolution ≤ 3m
Swath ≥ 30 km
Swath 3 Swath 14
NESZ (worst case) ≤ ‐19 dB
Swath‐3 Swath‐14
‐19.5 dB ‐21.2 dB
RASR (worst case) ≤ ‐17 dB ‐37.1 dB ‐28.5 dB
AASR ≤ 17 dB 26 0 dB 25 9 dBAASR ≤ ‐17 dB ‐26.0 dB ‐25.9 dB
Radiometric stability ≤ 0.5 dB 0.20 dB 0.10 dBy
Relative radiometric accuracy ≤ 0.5 dB 0.31 dB 0.22 dB
Absolute radiometric accuracy ≤ 1 dB 0.57 dB 0.34 dB
Phase stability (50 sec window) ≤ 5 degrees 4 37 ± 0 48 degrees
Table 4‐1 SM‐S performance requirements
Phase stability (50 sec. window) ≤ 5 degrees 4.37 ± 0.48 degrees
p q
5. Conclusions5. Conclusions
Consolidated panel design to allow for full performance compliance ofcustomer requirements S t lib ti d t h t i ti t f t System calibration and accurate characterization measurements of antennapatterns and subsystems to validate on‐ground instrument performancespatterns and subsystems to validate on ground instrument performances
6. References
[1] F. Cerezo, M. Fernández, A. Borges, J. Sánchez‐Palma, J. Lomba, R. Trigo, J. Ureña, E. Vez,M López ‘The Spanish Earth Observation Programme’ Advanced RF Sensors and RemoteM. López, The Spanish Earth Observation Programme , Advanced RF Sensors and RemoteSensing Instruments 2009[2] F. Monjas Sanz, M. I. Martín‐Hervás, ‘Dual polarized subarray for Spaceborne SAR at X‐band’, EUCAP 2009band , EUCAP 2009[3] M. Labriola, J.M. Gonzalez Arbesu, J. Romeu, I. Calafell, J. Closa, P. Saameno, J. Sanchez, A.
‘ f ( )’Solana, ‘AMOR: an Antenna MOdeleR for the Spanish SAR Satellite (PAZ)’, Advanced RFSensors and Remote Sensing Instruments 2009, Noordwijk, November 2009Sensors and Remote Sensing Instruments 2009, Noordwijk, November 2009[4] P. Saameño, J. Closa, M. Labriola, J. Sánchez Palma, A. Solana, F. López Dekker, A.García
d ‘ d d h f dMondejar, A. Broquetas, ‘Radiometric Budget Characterization of X‐Band SAR Instrument On‐Board PAZ’, Advanced RF Sensors and Remote Sensing Instruments, 2009Board PAZ , Advanced RF Sensors and Remote Sensing Instruments, 2009
Alb Z i @ i d [email protected]