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1Institut für Hochfrequenztechnk und RadarsystemeQue
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1Institut für Hochfrequenztechnk und Radar
Present and Future Air-borne & Space-borne Systems
Wolfgang KeydelDLR Oberpfaffenhofen
Microwaves & Radar InstituteD-82230 Oberpfaffenhofen Wessling, Germany
e-mail: [email protected] Address
Mittelfeld 4., D-82229 Hechendorf, GermanyTel.:+49-8152-980 523, Fax:+49-8152-980 525
e-mail: [email protected]
RTO LS-240 Polint, 2004
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2Institut für Hochfrequenztechnk und RadarsystemeQue
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2Institut für Hochfrequenztechnk und Radar
SRTM flight configuration
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3Institut für Hochfrequenztechnk und RadarsystemeQue
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3Institut für Hochfrequenztechnk und Radar
SRTM Within Shuttle Bay
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4Institut für Hochfrequenztechnk und RadarsystemeQue
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4Institut für Hochfrequenztechnk und Radar
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5Institut für Hochfrequenztechnk und RadarsystemeQue
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5Institut für Hochfrequenztechnk und Radar
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6Institut für Hochfrequenztechnk und RadarsystemeQue
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6Institut für Hochfrequenztechnk und Radar
X-SAR/SRTM Radar Specifications
225km45kmSwath
4,9/37,5°4.9/0.25°5,3/0,28°5.5 /0.14°3 dB Beam Elevat. /Azimuth -19 dB-18 dB -21 dB-20 dBElevation Side Lobe40,0 dB42.8 dB 41,8 dB43.5 dBMain Antenna Gain 0.7m x 8m0.7 m x 12 0.4m x 6m0.4 m x12mMain Antenna Area
1.7 kW3.5 kWRadiated Peak Power60 dBTotal Dynamic Range
25 m / 13 m20 m / 10 mRge Res.10 MHz/20 MHz BW
30m25 mAzimuth Resolution (4 looks)
36.5, 46.5,53, 5836.5,46.5,53,5855.554.5Off Nadir during Mission/°
15- 55 elec.15 - 55 elec.54-55 mech.15-55mech.Adjustable Off-Nadir /Degree >25 dB39 dBPolarization Isolation
5.3 GHz HV5.3 GHz HV9.6 GHz V9.6 GHz VVFrequency, Polarization
C-Band Secondary
C-Band Primary
X-Band Secondary
X-BandPrimary
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7Institut für Hochfrequenztechnk und RadarsystemeQue
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7Institut für Hochfrequenztechnk und Radar
Systems Operation Geometry
YIC S
ZI C S
Ou tbo ard C oo rd in ate System (OCS)
Xo cs
Yo cs
Zo cs
X IC S
B
Inb oard Co ordinate System (ICS)
–YIC S
–YO RB
L ook A ngle
C ro ss-Track A lo ng-Track (Velocity Vector)
B Y
• • •• • •
• • •• • •
- 22 5 k m- 80 k m
- 50 k m
- 6 2 k m
- 5 8 k m
- 6 1 m- 233 – 247 km
Flig
ht D
irec
tion
Tim
e
1 55 0 PR F 13 441 34 415 50
Inc ide nc e A ngle
ZIC S
45°
B e am 1B 2B 3B 4C H -po lC VC VCH
Z OR B 14°
X V
- 3 0 °- 6 0 ° - 4 3 °- 5 0 °- 5 6 °
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8Institut für Hochfrequenztechnk und RadarsystemeQue
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8Institut für Hochfrequenztechnk und Radar
•••
•••
•••
•
••
- 2 2 5 k m
- 8 0 k m
- 5 0 k m
- 6 2 k m
- 5 8 k m
Fli
gh
tD
ire
cti
on
1 5 5 0P R F
1 3 4 41 3 4 41 5 5 0
45 km
PRF 1700
Tim
e
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9Institut für Hochfrequenztechnk und RadarsystemeQue
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9Institut für Hochfrequenztechnk und Radar
Cargo Bay Payload Layout
Star Tracker(STA )
GPS A ntenna
X-B and Outb oard Elec tronics
F ORE
AF T
C an is terOutb oard Supp ort Stru ctu re (O SS)
C -Band M ain A ntenn aL -Band M ain A ntenna
X-B and M a in A ntenn a
GPS A ntenna
Pallet A ntenn a Trun ion
A ntenna C ore Stru ctu re (A CS)
A OD A Su ppo rt Pane l (ASP)
A stros Targ et Tracker (ATT )
IR U
An ten na Tru nio n (ATS)
GPS An ten na
GPS A ntenn a
M A ST
M ilkstoo l
A ntenna C ontrol le r (CP DU )
GPS A ntenna
LED Targets (OTA )Fl ip Hinge
X-Band Outb oard An ten na
A FT Elec tro nics Panel (A EP)
GPS Receivers
A FT
X-Band 2nd Ch an nel Electron ics
Elec . D is tance M eter (ED M )
C -To -L D ow nconverte r
O utbo ard A ntenna B racketOu tboard C orner C ube
C -Band Ou tboard A ntenna
B eam A uto-Tracker
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10Institut für Hochfrequenztechnk und RadarsystemeQue
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10Institut für Hochfrequenztechnk und Radar
SRTM-Result, Area around White Sands, New Mexico, USA.
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11Institut für Hochfrequenztechnk und RadarsystemeQue
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11Institut für Hochfrequenztechnk und Radar
Assessment of Interferometric Performance
22222quantprocresidualambiinst ϕϕϕϕϕϕ δδδδδδ ++++=
2
10arctan 20
=
ASR
ambiϕδ
Phase errors due to ambiguities:
Image Quality Parameters
SAR System Parameter
Antenna
Geometry
Timing
PRF Selection
SAR Performance
Spatial Resolution
Signal-to-Noise Ratio
Radiometric Resolution
Ambiguity Ratios
Height Errors
Optimization
Phase noise is a major source for height errors:
Example:
⇒ Height errors are sensitive tovarious SAR system parameters,especially choice of PRF.
ASR: Total ambiguityto signal ratio
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12Institut für Hochfrequenztechnk und RadarsystemeQue
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12Institut für Hochfrequenztechnk und Radar
X-SAR/SRTM Calibration Phases
• Preflight concept definition phase including sensor characterization,calibration algorithm development and implementation
• Ground campaigns during the mission
• 6 months commissioning phase: generation of static and dynamic calibration files, analysis and modeling of parameter drifts with temperature and time
• Operational calibration and validation
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13Institut für Hochfrequenztechnk und RadarsystemeQue
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13Institut für Hochfrequenztechnk und Radar
X-SAR/SRTM Error Budget
Performance Requirements
• Relative Height Accuracy(90 %) <6 m
• Absolute Height Accuracy(90 %) <16 m
X-SAR/SRTM Height Error Sources
•Baseline Tilt Angle
•Baseline Length
Instrument Phase
•Random Phase
Ambiguity Phase
• Atmosphere
• Position
• Calibration
• Slant Range
• Processing
14,4 m5,5 mTotal4,2 m4,o deg4,2 m4,0 degInstrument Phase2,6 m4,0 mm0,8 m1,3 mmBaseline Length13,4 m9 arcsec3,0 m2 arcsecBaseline Tilt AngleErrorAccuracyErrorAccuracyError Type
Absolute (11 Days)Relative (30 seconds)Height Error Examples (Middle of Swath)
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14Institut für Hochfrequenztechnk und RadarsystemeQue
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14Institut für Hochfrequenztechnk und Radar
Calibration Concept
Ocean Sea Level
Calibration
•Estimation of systematic errors•Monitoring of system parameters and instrument performance•Characterization of instrument parameters•Development of calibration models (parameter drifts as a function of time and temperature )•Ocean as reference height (sea surface height model)
Known orbit with respect to WGS 84 ellipsoid
Ground Control
PointOcean Sea
Level Calibration
Measured height
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15Institut für Hochfrequenztechnk und RadarsystemeQue
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15Institut für Hochfrequenztechnk und Radar
SRTM Baseline Measurement Breakdown
WGS
To Origin of WGS84
:)= (P -
WGS
GPSxPICSocsM
WGSicsM A- Pi+Gx Ei+ Antenna 1 Antenna 2
Inboard C-Band Phase Center
Inboard Coordinate System Origin
Outboard Coordinate System Origin
A
Pi
G2
Phase Center
B
Po
Inboard Area Centroid
Eo
Ei
To Origin of WGS84
B = Interferometric Baseline VectorP = Phase Center Position VectorA = ICS to OCS Origin VectorP = Location of GPS Antennas in WGS84G = GPS Antenna ICS/OCS LocationP =Antenna Area Cenroid LocationE = Offset Vectors between Area Centroids
Antenna Phase CentersM = Rotation Matrices to convert between
Coordinate Systems Responsibility Color Codes
---- Structure & Mechanics---- AODA---- C-RADAR---- Ground Data Processing
B = M (A - Pi Poocs( Eo+ICSM+- Ei )ics GPS GPS Outboard C-Band
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16Institut für Hochfrequenztechnk und RadarsystemeQue
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16Institut für Hochfrequenztechnk und Radar
Correction & Calibration of the X-SAR Data
Antenna 2
XCB
XDC
RFE
RAE
IFD
Antenna 1
Boom135MHz
1052MHz
263MHz
WG
Secondary Channel Primary Channel
STALO
X Combiner Box
X Down Converter
IF & Demodulator Unit, RF Adaptor Electronics RF Electronics
Critical Parts of the X-SAR Radar electronics
• Phase variation of radar receive signalin six individual paths: antenna panel to XCB including LNA’s
and phase shifters
• Down-conversion using 263 MHz signalgenerated in RFE (1052 MHz) & distributedover the mast to XDC, ± 4 deg phase variationat 263 MHz multiplied by 36 in down-conversion
•Phase variation of radar receive signal running at 135 MHz over the mast cable: ± 2deg over a temperature range between -10oC and -50oC
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17Institut für Hochfrequenztechnk und RadarsystemeQue
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17Institut für Hochfrequenztechnk und Radar
X-SAR/SRTM Receive Channels with Calibration Tone
6m Antenna & 6 LNA’s
Outboard Receive Channel
Radio Frequency Electronics
Inboard Receive Channel
12m Antenna
Combiner
Down Conversion
RF Adaptor Electronics
IF&Demodulator Electronics
9602 MHz
Mast Cables
I&Q Signals
1052 MHz
135 MHz 263 MHz
CAL Tone
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18Institut für Hochfrequenztechnk und RadarsystemeQue
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18Institut für Hochfrequenztechnk und Radar
X-SAR/SRTM Swaths over Bavaria (Calibration site)
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19Institut für Hochfrequenztechnk und RadarsystemeQue
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19Institut für Hochfrequenztechnk und Radar
D1-D18 1.5 m Corner reflectors GermanyD19-D24 3m Corner reflectorsD25-D27 RU1-Russia-Kitab-1 RU2-Russia-Zelenchukskaya-2RU3-Russia-Zvenigorod-3RU4-Russia-Irkutsk-4RU5-Russia-Bear_Lakes-5CH1-5 Switzerland-1-5SA1-2 South-Africa-1-2 NO1-2 Norway-1-2 EG1-3 Aegypten-1-3 BK1-6 Baikal-1-6KG1-Kirgisien-1-4 IS1-2 MIRBATS-ISRAELIS3-673-HILL-ISRAELIS4-MITSPE-ZOHAR-ISRAELIS5-HIDDEN-HILL-ISRAELIS6-SEDE-ZIN/minhat-north-ISRA IS7-SEDE-ZIN/minhat-south-ISRA IS8-BEER-SHEVA/goral-ISRAELIS9-BEER-SHEVA/hatserim-ISRAEL
X-SAR/SRTM Calibration Sites
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20Institut für Hochfrequenztechnk und RadarsystemeQue
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20Institut für Hochfrequenztechnk und Radar
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21Institut für Hochfrequenztechnk und RadarsystemeQue
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21Institut für Hochfrequenztechnk und Radar
AODA System OverviewInstruments Function Accuracy Rate
X Y ZGPS2 GPSR &4 GPSA
C-band area centroids (ACS and OCS) state vectors- Position (WGS 84)- Velocity (WGS 84)
Time tag
1m0.05m/s
1m0.05m/s
1m0.05m/s 1 Hz
Star TrackerAssembly (STA)
Estimates inertial attitude of ICSSTA boresight orientation wrt inertial space
InertialReferenceUnit (IRU)
Propagation of inertial attitudes between STA updates
roll5.0
0.05arcsec
pitch36.0
0.05arsec
yaw5.0
0.0.5arcsec
1 Hz
ASTROS (ATT)& Optical TargetAssembly (OTA)
Estimates the relative attitude and position of the OSS ->C-InSAR baseline and support antenna alignmentTracks 3 LED targets at 60 m distance
0.8arcsec
- 0.8arcsec
4 Hz
ElectronicDistance Meter(EDM)
Distance measurement to OCS and X-SAR backstructure- 2 for ICS to OCS vector length determination (red.)- 2 for ICS to inboard X-SAR area centroid Y & Z offsetdetermination
-0.5mm
0.5 mm -0.5mm
0.5Hz
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22Institut für Hochfrequenztechnk und RadarsystemeQue
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22Institut für Hochfrequenztechnk und Radar
SRTM Antenna Alignment
Bending in X-Y Plane (Yaw)Bending in Y-Z Plane (Roll) Twisting along Y (YPitch)
– YOCS
Cross Trac k
Alo
n gTra ck
Near
Outboard Antenna Foot print
Inbo ard Ante nna Footprint
F ar
– YICS
ZOCS
ZICS
XICS II XOCS
Cr oss Tr ac k
Alo
ngTrack
Ne ar F ar
Outboa rd Antenna Foot print
Inboard Antenna Foot print
– YOCS
– YICS
XICSXOCSXICS
ZICS II ZOCS
Cross Tr ack
Alon
gTrack
Near F ar
Outboard Antenna Foot print
Inbo ard Ante nn a Footprint
YICS = YOCS
XICS
XOCS
ZOCS ZICS
Loose SNR & SwathObserve: AODA Results,Radar Echo ProfilesMeasures:Adjust Outboard Structure in Pitch, Steer Main Antenna in Azimuth, Outboard Beam Tracking
Loose SNR & Swath,Baseline Vector ChangeObserve: AODA Results,Radar Doppler & -Echo ProfilesMeasures:Adjust Outboard Structure in Yaw, Steer Main Antenna in Azimuth, Outboard Beam Tracking
LooseSNR & SwathBaseline Vector Change
Observables:AODA Results Radar Echo Profile
Measures: Antenna Elevation Steering
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23Institut für Hochfrequenztechnk und RadarsystemeQue
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23Institut für Hochfrequenztechnk und Radar
Geometric Calibration
Differential Range DelaysUsing Data itself by Cross Correlation of Speckle Patterns between the
two Interferometric Channels
Common Range Delay, Time Tag/Velocity BiasesUsing Corner Reflectors, Calibration Sites: Oberpfaffenhofen, Mojave Desert, Australia
Baseline Length/Tilt, Orbit, Phase Offsets: Estimation from Short Ocean Data Takes before & after Ocean-land Crossing or from Ground Control Points
Residual Phase Errors (e.g. Multipath) & System Stability: Long OceanData Takes at the Beginning & End of the Mission
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24Institut für Hochfrequenztechnk und RadarsystemeQue
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24Institut für Hochfrequenztechnk und Radar
SIR-C Results
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25Institut für Hochfrequenztechnk und RadarsystemeQue
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25Institut für Hochfrequenztechnk und Radar
Interferometric Performance
Coherence
4 desert regions no problems so far
4 water surfaces sometimes decorrelate under calm wind conditions
Coregistration
4 currently better than 0.05 pixelShadow / Layover
4 layover no problem: < 0.06 % in alpine regions
4 shadow problems in alpine regions: ca. 7% of ground surface
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26Institut für Hochfrequenztechnk und RadarsystemeQue
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26Institut für Hochfrequenztechnk und Radar
SRTM Calibration:measured Height over Ocean
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27Institut für Hochfrequenztechnk und RadarsystemeQue
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27Institut für Hochfrequenztechnk und Radar
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28Institut für Hochfrequenztechnk und RadarsystemeQue
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28Institut für Hochfrequenztechnk und Radar
Mast Phase and Mast Temperature
-30
-20
-10
0
10
20
30
05. 22:00:00 05. 23:00:00 06. 00:00:00 06. 01:00:00 06. 02:00:00
MET
Tem
p 'M
ast_
58D
'
184,00
186,00
188,00
190,00
192,00
Mas
t Pha
se
at 2
63 M
Hz
Mast_58DMast Phase
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29Institut für Hochfrequenztechnk und RadarsystemeQue
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29Institut für Hochfrequenztechnk und Radar
Mast motion and antenna alignment
1.4 0.7 0 0.7 1.4
0 10 20 30 40 sec
+0,04
0,00
-0,04
Dynamic mast torsion (pitch axis)= max 0.05º
Dynamic mast deflection (yaw axis)= max 0.02º
Dynamic mast deflection (roll axis)= max 0.1º
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30Institut für Hochfrequenztechnk und RadarsystemeQue
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30Institut für Hochfrequenztechnk und Radar
Geometric Stability
excellent baseline stability:
4 ηinc=54.50 average +-0.20
4 data from shuttle nav. system
excellent antenna co-alignment:
4 Doppler differences ca. 50 Hz between both channels
small, coupled oscillations of shuttle and boom, will be compensated
44.55
44.60
44.65
0 5 10 15 20time [s]
0.10
0.14
0.18
0.22
0.26
0 5 10 15 20
time [s]44.70
Boom tip [m]
Shuttle attitude [deg]Boom tip
Shuttle roll attitude
Eineder, M. 2000
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31Institut für Hochfrequenztechnk und RadarsystemeQue
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31Institut für Hochfrequenztechnk und Radar
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32Institut für Hochfrequenztechnk und RadarsystemeQue
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32Institut für Hochfrequenztechnk und Radar
Results (I)
SRTM/X-SAR Radar amplitude image of the peninsula of Hokkaido/Japan, MET 5/07:55:00
Eineder, M. 2000
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33Institut für Hochfrequenztechnk und RadarsystemeQue
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33Institut für Hochfrequenztechnk und Radar
Results (III)
SRTM/X-SAR coherence map of the peninsula of Hokkaido/Japan, MET 5/07:55:00
Eineder, M. 2000
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34Institut für Hochfrequenztechnk und RadarsystemeQue
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34Institut für Hochfrequenztechnk und Radar
Results (IV)
SRTM/X-SAR DEM of volcano Komaga-take on Hokkaido/Japan, MET 5/07:55:00
Eineder, M. 2000
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35Institut für Hochfrequenztechnk und RadarsystemeQue
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35Institut für Hochfrequenztechnk und Radar
Phase unwrapping: Komaga-take (1131m)
Moderate topography: Minimum cost flow (MCF) method gives excellent results!
Eineder, M. 2000
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36Institut für Hochfrequenztechnk und RadarsystemeQue
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36Institut für Hochfrequenztechnk und Radar
Receive Signal Phase - Corrections
Antenna 2LNA's
XCB
XDC
RFE
RAE
IFD
Antenna 1
Boom
135MHz
1052MHz
263MHz
WG
Secondary Channel Primary Channel
STALO
6. Due to temperature variations of the mast cable there were phase errors in the receive path-> Phase correction with Mast Phase HK (max. 9°)(max. expected error for receive signal 330° within a orbit )
7. Different gain settings (70 dB … 80 dB) was used-> Correction of the phase jumps for different Gain Att. Settings with Gain Att. characterization data.
(max. expected phase jump 60°)8. Due to a low temperature variation (about 2°C) of the shuttle cold plates there were minor phase errors in the receive path (RAE, IFD,RFE)-> Phase correction with Cal Tone ( max. expected error ?)
9. Low temp. variation for Coax Cable with Ref. Signal -> No Correction possible (max. expected error < 0.1°/10 min, for 1052 MHz)
1. No beam steering was done during mission -> No correction necessary
2. Variation of XOA coax cable temperature 5°C/orbit -> Phase correction with Cal Tone ( max. expected error 0.2°)
3. Cal Tone was in ‘cycling mode’-> Each Cal Tone path has a different Cal Tone Offset (max. expected difference 360°)4. Cal Tone Level was following IFD gain (XDC/RAE Cal Tone Att.)-> Correction of the phase jumps for different XDC/RAE Cal Tone Att. Settings with Cal Tone Att. Characterization data. (max. expected phase jump 60°)
5. Due to major temperature variation of XDC there were high phase errors in the receive path-> Phase correction with Cal Tone (max. expected error?)
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37Institut für Hochfrequenztechnk und RadarsystemeQue
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37Institut für Hochfrequenztechnk und Radar
Transponder in ERS 1 Image
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38Institut für Hochfrequenztechnk und RadarsystemeQue
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38Institut für Hochfrequenztechnk und Radar
range / m0
2630
526105215782104
0 20484096
61448192
10240
azimut / m
ampl
itude
PBR = 32,61dB
0,0
0,5
1,0
1,5
2,0
2,5RCS=48,70dBm²
Fig. 1 The echo of the uncoded transponder in compe- tition with the echoes of other targets
range / m0
2630
52610521578
2104
azimut / m
ampl
itude
0,0
0,5
1,0
1,5
2,0
2,5
PBR = 34,01dB
RCS=50,59dBm²
0 20484096
61448192
10240
Fig. 3 RCS and PBR (peak to background ratio) of the code4 transponder
range / m 0
2630
526105215782104
azimut / m
ampl
itude RCS=44,04dBm²
PBR = 29,98dB
0,0
0,5
1,0
1,5
2,0
2,5
0 20484096
61448192
10240
Fig. 2 RCS and PBR (peak to background ratio) of the code7 transponder
02630
5261052157821040
400800
12001600
2000
azimut / m
ampl
itude RCS=33,15dBm²
0,0
0,15
0,3
0,45
0,6
PBR = 21,01dB
00range / m
Fig. 4 RCS and PBR (peak to background ratio) of the transponder with patch antennas
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39Institut für Hochfrequenztechnk und RadarsystemeQue
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39Institut für Hochfrequenztechnk und Radar
Space Borne SAR Development Line
Antenna SAR2015 ?
ERS-11991
ENVISAT2003
TerraSAR2006
RadarSAT1995
6 Sensors2500kg
10 Sensors2145kg
SAR only480kg
SAR only2750kg
SAR only100kg ?
1m x 12m750kg
1,4m x 15m750 kg
0,7m x 4,8m150kg
1m x 12m18kg
(1,5 kg m-2)
1m x 12m530 kg
From SAR Antenna to Antenna SAR
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40Institut für Hochfrequenztechnk und RadarsystemeQue
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40Institut für Hochfrequenztechnk und Radar
Basic ERS-1/2 SAR Characteristics
30m x 26.3 m
ResolutionAz x Rge4.8 kWPeak power
100 kmSwath width15.55 MHzBandwidth
23o nominalIncidence angleLinear VVPolarisation
10 m x 1 mAntenna size5.3 GHz Frequency
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41Institut für Hochfrequenztechnk und RadarsystemeQue
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41Institut für Hochfrequenztechnk und Radar
ENVISAT (Start 28 Febr. 2002)
ESA
SCIAMACHY
AATSRMIPAS
GOMOS
RA-2
MERIS
ASAR
DORIS
MWR
LRR
ESA
ASAR-Antenna(ca. 10 m x 1.33 m
and 320 T/R-Modules)
• Most ambitious Remote Sensing satellitefor environmental monitoring• Unique combination of 10 remote sensinginstruments• ASAR will ensure the continuation of the successful ERS-1/2 program• Due to different transmit frequencies between the ERS-2 and ASAR instrument, interferometrybetween these instruments will be very limited
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42Institut für Hochfrequenztechnk und RadarsystemeQue
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42Institut für Hochfrequenztechnk und Radar
ENVISAT-ASAR Modes
HH or VV. Small imagette (5 km ..10 km x 5 km) at regular intervals of 100 km along-track, can be positioned anywhere in an Image Mode swath. Up to two positions in a single swath or in different swaths with acquisitions alternating between one and the other (successive imagettes will have a separation of 200 km between acquisitions at a given position). Conversion to wave spectra for ocean monitoring.
Wave Mode
HH or VV. Spatial resolution ≈ 1000 m x 1000 m up to a full orbit of coverage.
Global Monitoring
VV or HH, 400 km by 400 km wide swath image. Spatial resolution ≈ 150 m by 150 m. WideSwath
HH/HV, VV/VH, HH/VV. Two co-registered images per acquisition. Spatial resolution ≈ 30 m
Alternating Polarisation
HH or VV ,7 selectable swaths. Swath width 56 km (swath 7) & 100 km (swath 1) Spatial resolution ≈ 30 m
Image Mode
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43Institut für Hochfrequenztechnk und RadarsystemeQue
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43Institut für Hochfrequenztechnk und Radar
RadarSAT 1
15 m x 1,5 m
Antenna Size
14 orbits/day
Sun-synchronous
300 WMean Power
18 hrsAscending Node
5 kWPeak Power
6 DaysNorth of 80°S101 minPeriod11,6 13,3, 30 MHz
RF Bandwidth
4 DaysNorth of 70°N98,6 °InclinationHHPolarization
1 DayNorth of 70°N793 km –821 km
Altitude5,3 GHzFrequency
Maximum Coverage Access Period
Orbit Characteristics
RadarSATSAR Characteristics
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44Institut für Hochfrequenztechnk und RadarsystemeQue
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44Institut für Hochfrequenztechnk und Radar
RadarSAT 2 Modes (right & left looking!!)
ultra fine
standardwide swath
fine res.Scan SAR extended beam
500 km
250 km
49°20°
Frequency: C-Band (5,4 GHz)
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45Institut für Hochfrequenztechnk und RadarsystemeQue
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45Institut für Hochfrequenztechnk und Radar
RadarSAT-2 Modes and Performance3 m x 3 m400km- 550km20 kmUltra- fine Wide
11m x 9 m400km- 750km50 kmMultiple FineSelective Pol.Transmit H or VReceive H or V
11m x 9m400km – 600km25 kmFine Qad P25m x 28m250km – 600km25 kmStandard Qad P
Full Pol. Trans. H,V alternatingRec. H & V
20m x 28m750km –1000km70 kmHigh Incidence40m x 28m125km – 300km170 kmLow IncidenceSingle Pol. HH50m x 50m300km – 720km300 kmScanSARNarrow100m x100m250km – 750km500 kmScanSAR Wide10 m x 9 m525km – 750km50 kmFine25 m x28 m250km – 650km 150 kmWide25 m x28 m250km - 750km100 kmStandardSelective Pol.
Transmit H or V Receive (H or V) or (H & V)
ResolutionRge x Az
SwathCoverageto Left ore Right
Nominal Swath
Beam Mode
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46Institut für Hochfrequenztechnk und RadarsystemeQue
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46Institut für Hochfrequenztechnk und Radar
TerraSAR – X Payload Key Specifications
5 - 300 MHzChirp bandwidth2260 WRadiated peak output power
3kHz – 6,5 kHz Operational PRF15° - 60°Incidence angle access range
5.0 dBSystem Noise0.75°, ± 19.2°Scan range (az., el.)
20%Duty Cycle Spotlight
4.78 m x 0.70 mAntenna size (az. x el.)
18%Duty Cycle Stripmap
9.65 GHzCenter frequency
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47Institut für Hochfrequenztechnk und RadarsystemeQue
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47Institut für Hochfrequenztechnk und Radar
TerraSAR-XHigh geometric and radiometric resolution with an experimental very high resolution 300 MHz modeDual-Polarization mode where two of the possible polarizations (HH & VV, HH &HV or VV & HV) can be acquired simultaneouslyLong term observation with the opportunity for multi-temporal imagingPrecise attitude and orbit control and determination as well as phase stability e.g. for Repeat-Pass InterferometryHigh synergy potential with other frequency bands (L-Band: ALOS, TerraSAR-L, C-Band: ASAR, RadarSAT)New imaging modes like sliding/ starring Spotlight beside ScanSARFull operator access to the highly flexible active phased array antenna for the realization of new imaging modes and the acquisition of custom designed image product
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48Institut für Hochfrequenztechnk und RadarsystemeQue
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48Institut für Hochfrequenztechnk und Radar
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49Institut für Hochfrequenztechnk und RadarsystemeQue
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49Institut für Hochfrequenztechnk und Radar
ALOS/PALSAR 1,270 GHZAdvanced Land Observing Satellite/Phased Array L-Band SAR
240120, 240240240Data rate/Mbps20 ~ 65250 ~ 35040 ~ 7040 ~ 70Swath/km
24 ~ 89m100m (multi look)
14 ~ 887 ~ 44Range Res./m8 ~ 3018 ~ 438 ~ 608 ~ 60Incident angle/°
HH, VV, HV, VH
HH or VVHH+HV or VV+VH
HH or VVPolarization14MHz14MHz, 28MHz14MHz28 MHzChirp Bandwidth
Experimental Polarimetric
ScanSARHigh Resolution Mode
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50Institut für Hochfrequenztechnk und RadarsystemeQue
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50Institut für Hochfrequenztechnk und Radar
ALOS/PALSAR
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51Institut für Hochfrequenztechnk und RadarsystemeQue
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51Institut für Hochfrequenztechnk und Radar
SAR-Lupe, Launch 2005
Strip MapGround Velocity
7km/s
High Resolution within
8 km x 60 km
Images/day > 30Total Interest Area
Spot-LightVelocity Reduction
Highest Resolution within
5,5km x 5,5 km
ca. 24 m3Volume
> 128 GbOn Board Memory10 yearsLife time
250 WAv.PowerConsumption
770kgWEIGHT
S-Band X-Band
Telemetry:CommandData
<11 hoursmean<19 hours 95%
System ResponseTime
>30Images per Day
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52Institut für Hochfrequenztechnk und RadarsystemeQue
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52Institut für Hochfrequenztechnk und Radar
Stripmap & Spotlight Mode byChange of Ground Velocity
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53Institut für Hochfrequenztechnk und RadarsystemeQue
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53Institut für Hochfrequenztechnk und Radar
SAR-Tomography2-dimensional image of a Cut (τοµή) through a 3-dimensional Objekt
Interferometriy with several vertikal Baselines
y
z
x
12..N-1N
n
rL
Multiple horizontal Flights
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54Institut für Hochfrequenztechnk und RadarsystemeQue
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54Institut für Hochfrequenztechnk und Radar
Accuracies airborne SAR
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55Institut für Hochfrequenztechnk und RadarsystemeQue
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55Institut für Hochfrequenztechnk und Radar
Accuracies of ERIM SAR
Accuracies obtained with Airborne One Pass Interferometry in Bosnia with ERIM SAR
0.15 m – 0.5 m5 mR > 50 m
1 mR <50m
5 m5 m1m
0.5 m – 1 m10R > 100 m
2 mR <100 m
5 m10 m3 m
1 m – 3 m10 mR >200 m
3 mR < 200m
10 m10 m10 m
VerticalNear vs. Far
HorizontalFar Range
HorizontalNear Range
VerticalHorizontalPosts
Relative accuracyAbsolute accuracy
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56Institut für Hochfrequenztechnk und RadarsystemeQue
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56Institut für Hochfrequenztechnk und Radar
Height accuracies obtained over Different Terrain Types
Different Airborne SAR, X-band
Laser ScanningDEM
22 cmFlat,HeightVariations ≤ 100m
MeadowsOpen Fields
Maastricht, TheNetherlands
D-GPS25 cmHilly,HeightVariations ≤ 500m
Sparse Vegetation
Juazeirodo Norte Brazil
24Triogonometric Points
17 cmFlat,HeightVariations ≤ 150m
MeadowsOpen Fields
SolothurnSwitzerland
TheodoliteMeasurements
5 cmFlat,HeightVariations ≤ 1m
Tidal FlatsBremerhafenGermany
ValidationRef. Source
ValidatedAccuracy
Type of Topography
LandCoverage
Area
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57Institut für Hochfrequenztechnk und RadarsystemeQue
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57Institut für Hochfrequenztechnk und Radar
Measured Height Deviations from Measured Reference
Reference Values Obtained from Measurements with 24 Trigonometric Reference Points[J.Moreira 2000 MFFU
5.49 m- 3.25 m1.66 m1.28 mDHM25(official DEM)
0.77 m- 0.87 m0.43 m0.40 mLaser Scanner
0.21 m- 0.54 m0.17 m0.14 mAES – SAR (X-Band)
1.38 m- 2.20 m0.97 m0.77 mDigital Camera
Maximum Height Deviationfrom Reference
Minimum Height Deviationfrom Reference
StandardDeviationσΗ
Absolute MeanHeight Deviation
Sensor
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58Institut für Hochfrequenztechnk und RadarsystemeQue
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58Institut für Hochfrequenztechnk und Radar
Multistatic SAR Interferometry: „Cartwheel“
Master Satellite TransmitterENVISAT, RadarSAT, etc
Receiver
Trans-mitter
3 Passive Receiver Satellite:On Master Orbit Master with equal Eccentricity, 120º shiftedAlong- & Across-Track- BaselinesStable maximal vertical Baseline
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59Institut für Hochfrequenztechnk und RadarsystemeQue
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59Institut für Hochfrequenztechnk und Radar
GPS Based Global Multistatic SAR System
Digital Beamformingon Receive
TransmittL-Band
Use GPS ChannelsP-Code BW=10MHz
Add Geostanionary SatelliteComunicationRS Transmitter
Add RS-Channel to GPS SatellitesHigh PowerLarge Bandwidth
Introduce Multisatellite Formation
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60Institut für Hochfrequenztechnk und RadarsystemeQue
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60Institut für Hochfrequenztechnk und Radar
Proposals for future research and development activitiesFuture SAR will be Software based, Highly integrated, Multistatic Systems
Problems:High Power Sources for Geostationary Satellites require New Waveform Generation or Modulation Schemes, Forward Scattering leads to Conflicts with Requirements for High ResolutionPolarization Behavior of Forward Scattered Waves not very well knownRadiometric & Geometric Calibration Problems as well as Multi-path Effects
mainly with respect to Polarimetric, Interferometric Bistatic radar in direct side direction
???
Do We Need Different Radars for Different Users?
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61Institut für Hochfrequenztechnk und RadarsystemeQue
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61Institut für Hochfrequenztechnk und Radar
What to do?
•Develop beside of Component and Subsystem Technology Airborne Demonstratorsas Preparation for dedicated Short-Term Space Missions
•Build Experimental Systems with Digital Beam Forming Capability
•Develop new appropriate Waveform Generation & Modulation Schemes
•Carry out Experiments for Bistatic SAR Systems (ground based, airborne,space borne using existing Instruments & Satellites)
•Study Bistatic Polarization Behavior of Electromagnetic Waves especially RCS
•Develop Real Time Processors & Real Time Classifiers
•Do Everything at the Platform as an End-to-End System
•Study Time Synchronization Via Satellites
SAR is not a Stand Alone Technique for Reconnaissannce and Remote Sensing,Enhanced Fusion with other Sensor Systems, Techniques &Technologies is
Indispensable