TerraSAR-X Upgrade to a Fully Polarimetric Imaging...

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TerraSAR-X

TerraSAR-X Upgrade to a Fully Polarimetric Imaging Mode

German Aerospace Center (DLR)

Alberto Moreira

82230 Oberpfaffenhofen, Germany

16. January 2003

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TerraSAR-X

TerraSAR-X, a National Science Mission with Commercial Potential

Astrium- Platform Development- Instrument Development- Launch on Dnepr-1 (2005)

DLR- Project Management- G/S Development & Ops- Instrument Ops and Cal- Science Coordination

Infoterra- Service Infrastructure- Information Products- Commercial Exploitation

Main Mission Goals:• Provision of TerraSAR-X data and products for scientific applications• Commercial exploitation of remote sensing data

Public Private Partnership

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TerraSAR-X

X-Band DownlinkAntenna

X-Band Active Array Antenna

Basic Satellite and Instrument Characteristics

Downlink• No direct data transmission to the ground• 256 Gbit on-board data storage (global coverage)• 300 Mbit/sec downlink data dump in X-Band

Instrument• Active array antenna (electric beam steering/multipol)• X-Band multi-mode SAR Sensor (left and right looking)

- ScanSAR Mode (16 m resolution, 100 km swath width)

- StripMap Mode (3 m resolution, 30 km swath width)

- SpotLight Mode (1...2 m resolution, 5...10 km x 10 km)

Satellite• 1023 kg wet mass• 800 W orbit average power

Solar Generator

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TerraSAR-X

Satellite Control Centerand Data Processing

in Oberpfaffenhofen / Germany

DLR GroundstationWeilheim / Germany

DLR GroundstationNeustrelitz

S-Band X-Band

DNEPR Launch

TerraSAR-X Mission Profile

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TerraSAR-X

The TerraSAR-X Sun-Synchronous Repeat Orbit

• Sun synchronous orbit (dusk/dawn)• Repeat period: 11 days

• Area revisit time: 4.5 days 100%(with left & right looking) 2.5 days 95%

• Orbits per day: 15

• Orbits per repeat cycle: 167

• Equatorial crossing time: 18:00h ascending pass

• Inclination: 97.44°

• Altitude at equator: 514.8 km

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TerraSAR-X

Instrument Key Parameters

Center Frequency: 9.65 GHz (X-Band)Transmit Bandwidth: 5 ... 150 MHz nominal; 300 MHz experimentalTR Module RF Output Power: 38.5 dBm nominal; 39.0 dBm max.Nominal Radar Duty Cycle: 18 % nominal; 20 % max.Radiated peak power output: 2260 WSystem Noise Figure: 5 dBQuantization of Signal: 8 bit I / 8 bit QSAR Data Compression: online BAQPulse Repetition Frequency Range: 3 ... 6.5 kHzPolarization: HH / VV / HV / VH

Antenna Dimension Azimuth: 4.784 m Elevation: 0.704 m Beamwidth (uniform excitation) Azimuth: 0.33° Elevation: 2.3°Scan Angle Azimuth: ± 0.75° Elevation: ± 19.2°

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TerraSAR-X

Strip Map ModeResolution: 3 m × 1,5 m ... 3,5 mScene Size: 100 km × 30 km

Flight direction

Nadir Track

45°

20°

SwathWidth100 km

Scan SAR Mode

Resolution: 3 m × 1,5 m ... 3,5 mScene Size: 100 km × 100 km

Spotlight Mode

Resolution: 1 m × 1,5 m ... 3,5 mScene Size: 5 km...10 km × 10 km

• The data collection incidence angle range is from 15° to 60°

• Dual polarisation data acquisition is possible in all operational modes

• 300 MHz experimental mode with ca. 0.6 m slant range resolution

• Further experimental modes are feasible due to the Dual Receiving Antenna

TerraSAR-X Imaging Modes

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TerraSAR-X

TerraSAR-X Products

Product Coverage Resolution Polarisation NESZ FullPerformance

Range

300 MHzExp.- Mode

10 x 5 km2 (0.6 -1.5)m x 1 m full pol

High Resol.Spotlight

10 x 5 km2 (1.2 - 3) m x 1 m full pol < -19 db 20 - 550

Spotlight 10 x 10 km2 (1.2 - 3) m x 2 m full pol < -19 db 20 - 550

Stripmap 1 30 km 3 m x 3 m full pol < -19 db 20 - 450

Stripmap 2 30 km 3 m x 6 m full poll < -19 db 20 - 450

ScanSAR 100 km 16 m x 16 m(5 looks)

full pol < -19 db 20 - 450

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TerraSAR-X

Application Areas

© Infoterra

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TerraSAR-X

Experimental Airborne SAR: E-SAR

• Flexible multi-channel SAR-System

• P-, L-, S-, C- and X-Band

• Full polarimetric in P- and L-Band

• High-resolution Imaging (up to 0.5 m

resolution in azimuth)

• Along- and Across-Track Interferometry

• Real-time SAR Processing

• Innovative Imaging Modes

(polarimetric SAR interferometry and tomography)

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TerraSAR-X


















• Innovative Imaging Modes (polarimetric

SAR interferometry and tomography)

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TerraSAR-X























• High-resolution Imaging (up to 0.5 m resolution in azimuth)



• Innovative Imaging Modes (polarimetricSAR interferometry and tomography)

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TerraSAR-X























• High-resolution Imaging (up to 0.5 m resolution in azimuth)



• Innovative Imaging Modes (polarimetricSAR interferometry and tomography)

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TerraSAR-X

POLARIMETRY

Testsite Airfield Oberpfaffenhofen, L-Band Polarimetric Color Compositered = even bounce, green = volume, blue = odd bounce

INTERFEROMETRY (XTI)

ProSmart Testsite EHINGEN, DEM from single-path interferometry,

Mosaic of three parallel stripes

The Island Ameland in the Dutch Wadden Sea, X-Band ATI Image, surface current velocities,Colour coded: blue = land surface, yellow = max. velocity (2 m/s)

INTERFEROMETRY (ATI)

E-SAR Imaging Modes

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TerraSAR-X

POLARIMETRIC INTERFEROMETRY

Crop Field Near Solothurn, Switzerland, Estimated

Vegetation Height = 2.3 m

Testsite Airfield Oberpfaffenhofen, 3D Tree-Heights

E-SAR Imaging Modes

Nymphenburg Castle & Park, Munich City, X-Band, HH-Polarization, Azimuth 4-Look Detected Image

Single Look Complex & Multi-Look Detected Images

E-SAR Products

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TerraSAR-X

Geocoded DEM Mosaics

ProSmart Testsite EHINGEN,DEM Mosaic of three

geocoded E-SAR X-Band DEMs

Geocoded Swath Mosaics

ProSmart Testsite EHINGEN,Image Mosaic of three

geocoded E-SAR L-Band Images

Multi-Frequency Images

Oberpfaffenhofen,red = X-Band, green = L-Band, blue = C-Band

E-SAR Products

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TerraSAR-X

Simulated Multitemporal TerraSAR-X Product

Testsite Ehingen (3 m resolution)

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TerraSAR-X

Land-Use Classification from Simulated TerraSAR-X Multipol Data

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TerraSAR-X

Dual Receive Antenna

A second receiving channel, which was integrated for redundancy reason, will now be used to enable new operating modes.

Principle

• For transmit the full antenna is used

• For receive the antenna is ‚electrically‘ divided into two halves in azimuth direction,i.e. two independent receive channels are available

New Experimental Modes

• Along track interferometry (ATI)(Moving Target Indication, Widespread Traffic Control, Ocean Current Measurement)

• Quad polarization(Sea/Ice, Snow Cover, Urban Environment)

• Enhanced azimuth resolution for stripmap mode

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TerraSAR-X

H-Pol

ϕ

G

HPA

LNA

Amplitude

Phase

Circulator

Limiter

Coupler

Pol-Switch

Radiator

Radiator

V-Pol

RF-Interface

Scheme of T/R Module Unit

CalibrationInterface

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TerraSAR-X

H-Pol

ϕ

G

HPA

LNA

Amplitude

Phase

Circulator

Limiter

Coupler

Pol-Switch

Radiator

Radiator

V-Pol

RF-Interface

Scheme of T/R Module Unit: Transmit Path


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TerraSAR-X

H-Pol

ϕ

G

HPA

LNA

Amplitude

Phase

Circulator

Limiter

Coupler

Pol-Switch

Radiator

Radiator

V-Pol

RF-Interface

Scheme of T/R Module Unit: Receive Path


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TerraSAR-X

Dual Receiving Antenna Mode

TerraSAR-X with Phased Array Antenna

TerraSAR-X with Phased Array Antenna

TerraSAR-X with Phased Array Antenna AND

Dual Receiving Mode

TerraSAR-X with Phased Array Antenna AND

Dual Receiving Mode

A/D

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Distribution Network

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Standard Receiving Mode

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TerraSAR-X

Nadir Track

45°

25°

Swath Width

Full Performance Range

Incidenceangle

300 km

40 km

Overlapping

10 km

Flight direction

<_ 1500 km

15°

60°

Data Collection Range

L max

750 km

StripMap /ScanSAR Mode

Potential Applications of a Dual Receiving Antenna Upgrade

1) Along-Track Interferometry

• Widespread Traffic Control • Moving Target Indication• Water Current Measurement

2) Full Polarimetric X-Band Data Acquisition

• Natural Bare Surfaces• Agriculture• Forestry• Sea/Ice• Snow Cover• Urban Environment

3) Enhancement of Azimuth Resolution

• 1,5 m x 1 m (azimuth x ground range

4) Additional Calibration Strategies

Required costs for the hardware

upgrade is less than 1 %

of the total satellite costs

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TerraSAR-X

Characteristics and Potential ofFull Polarimetric X-Band Data

Characteristics:• Low penetration depth due to short wavelength

• Detection of small scale roughness differences

Potential and Current Status:• X-Band fully polarimetric data are currently used for military applications

• Civilian earth observation applications have been disregarded in the past

• Expanded potential for target classification and identification

• Complementary information to L-Band

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TerraSAR-X

Potential Applications for Full Polarimetric X-Band Data

Natural Bare Surfaces:

Detection of small scale roughness differences:⇒ Ice (smooth surfaces) and geological applications

Agriculture:

Higher sensitivity to leaf and branch geometry:⇒ Classification of different agricultural vegetation types

Forestry:

Sensitivity to leaf and branch structures:⇒ Tree species determination

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TerraSAR-X

Potential Applications for Full Polarimetric X-Band DataSea / Ice:

Separation of volume and surface scattering components:⇒ Water/ice separation⇒ Ice classification and operational ice monitoring

Snow Cover:

Higher dynamic range of the surface scattering magnitude in X-Band:⇒ Determination of the snow/water equivalence used for hydrological

modelling⇒ Determination of snow depth, equivalent grain size, snow extinction

coefficient

Urban Environment:

Man-made scatterers are showing a strongly polarised behaviour:⇒ Localisation, identification and/or classification of such scatterers⇒ Improvement of mapping and cartography capabilities

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TerraSAR-X

Summary

• TerraSAR-X is a high-resolution, next generation X-Band radar satellite (launch: 2005)

• TerraSAR-X is the logic scientific/technological continuation of the highly successful national missions X-SAR (1994) and SRTM (2000).

• Provision of remote sensing data and products for scientific applications and commercial exploitation within a public private partnership between DLR and Astrium/Infoterra.

• A new class of space borne high quality X-band SAR images will be produced due to the high resolution capability and to the high flexibility of the antenna (electric beam steering).

• Operational data acquisition in Stripmap, ScanSAR and Sliding Spotlight mode.

• Multiple polarimetric X-band data will be available where several strategies for polarimetric data acquisition are functionally realized by the instrument.

• The potential for multi-temporal imaging as well as repeat-pass interferometry is given.

• The Dual Receive Antenna offers the potential of along track interferometry, full polarimetricdata acquisition and resolution enhancement.

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TerraSAR-X

Future SAR Systems

?

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TerraSAR-X

radar illuminator (€ € €)

(e.g. ENVISAT, ALOS, RadarSAT, TerraSAR)

receive-only micro satellites (€)

Micro-satellite Configuration suited to Pol-InSAR

Future SAR Systems

TerraSAR-X Upgrade to a Fully Polarimetric Imaging...

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