present and future air-borne & space-borne...

Que

llena

ngab

e

1Institut für Hochfrequenztechnk und RadarsystemeQue

llena

ngab

e

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

Que

llena

ngab

e


llena

ngab

e


SRTM flight configuration

Que

llena

ngab

e


llena

ngab

e


SRTM Within Shuttle Bay

Que

llena

ngab

e


llena

ngab

e


Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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 °

Que

llena

ngab

e


llena

ngab

e


•••

•••

•••

•

••

- 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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


SRTM-Result, Area around White Sands, New Mexico, USA.

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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)

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


X-SAR/SRTM Swaths over Bavaria (Calibration site)

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


SIR-C Results

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


SRTM Calibration:measured Height over Ocean

Que

llena

ngab

e


llena

ngab

e


Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


Que

llena

ngab

e


llena

ngab

e


Results (I)

SRTM/X-SAR Radar amplitude image of the peninsula of Hokkaido/Japan, MET 5/07:55:00

Eineder, M. 2000

Que

llena

ngab

e


llena

ngab

e


Results (III)

SRTM/X-SAR coherence map of the peninsula of Hokkaido/Japan, MET 5/07:55:00

Eineder, M. 2000

Que

llena

ngab

e


llena

ngab

e


Results (IV)

SRTM/X-SAR DEM of volcano Komaga-take on Hokkaido/Japan, MET 5/07:55:00

Eineder, M. 2000

Que

llena

ngab

e


llena

ngab

e


Phase unwrapping: Komaga-take (1131m)

Moderate topography: Minimum cost flow (MCF) method gives excellent results!

Eineder, M. 2000

Que

llena

ngab

e


llena

ngab

e


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?)

Que

llena

ngab

e


llena

ngab

e


Transponder in ERS 1 Image

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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)

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


ALOS/PALSAR

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


Stripmap & Spotlight Mode byChange of Ground Velocity

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


Accuracies airborne SAR

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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


MeadowsOpen Fields

SolothurnSwitzerland

TheodoliteMeasurements


Tidal FlatsBremerhafenGermany

ValidationRef. Source

ValidatedAccuracy

Type of Topography

LandCoverage

Area

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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

Que

llena

ngab

e


llena

ngab

e


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?

Que

llena

ngab

e


llena

ngab

e


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

present and future air-borne & space-borne...

Documents