TanDEM-X: Mission and Science Exploration Irena Hajnsek & Alberto Moreira TDX Science Team German Aerospace Center (DLR) Microwaves and Radar Institute Folie 1 irena.hajnsek@dlr.de - 25.01.2007 Primary Mission Goal The main goal of the TanDEM-X mission is the generation of a world-wide, consistent, timely and high-precision digital elevation model (DEM) according to the HRTI-3 standard Demonstration of new SAR Techniques (ATI, MTI, Digital Beamforming, Pol- InSAR, etc.) Airborne Product comparison LIDAR Airborne SAR 5 Photogrammetry HRTI / DTED Level 4 TanDEM-X SRTM-C (restricted) SPOT 5 HRS ERS Tandem 3 SRTM-X HR Satellites Aster SRTM-C 2 (free) USGS GTOPO30 1 0 Coverage in Mio km² 0 50 Microwaves and Radar Institute Folie 2 1
HRTI-3 DEM Specification Requirement Specification Value Horizontal Post Spacing fixed latitude/longitude raster 0.4 arcsec (~ 12 m) Horizontal Accuracy 90 % circular error 10 m Absolute Vertical Accuracy 90 % single point error 10 m Relative Vertical Accuracy 90 % point-to-point errors 2 m 1° Definition of 90% point-to-point relative height error Δ h errors: 1° ⋅ Δ ~ 2 h point-to-point errors Δ h (90% confidence interval) absolute height error single point errors Δ ≈ ⋅ σ 90 % h 2 . 33 (90% confidence interval) HRTI h Microwaves and Radar Institute Folie 3 TanDEM-X Radar Techniques and Application Areas TanDEM-X Application Across-track Along-track New Techniques Bistatic Processing Pol-InSAR Digital Beamforming Super Resolution Formation Flying InSAR Processing Land Environment Glaciology/Hydrology Geology Land Cover & Vegetation Oceanography Hydrology/Glaciology Traffic Oceanography Digital Elevation Model Radar Data Product (DEM) (RDP) Microwaves and Radar Institute Folie 4 2
TanDEM-X Product Classes DEM Products Radar Data Products • Standard DEMs • TanDEM-X provides data for - Δ h = 2m @ 12m posting (HRTI-3) - along-track interferometry - also: 1m @ 25m and 0.5m @ 50m - polarimetric SAR interferometry - four phase centre MTI 4m @ 6m (on special request) - digital beamforming, … - global access • Customised DEMs • Policy - user is responsible for higher level - improved resolution data production (e.g. 1m @ 6m ~ HRTI-4) - supporting analysis by DLR - multiple DEMs (different seasons/years) • Deliverables - only on local/regional basis • Supporting information - SLC SAR images - auxiliary data (baselines, …) - geocoded SAR images - interferograms (if applicable) - coherence maps - SAR raw data (on special request) - height error maps Microwaves and Radar Institute Folie 5 Scientific User Requirements Survey 1. Justification and Needs: General frame (application area, needs, National/European/International relevance, justification) 2. Technical Requirements: Quantitative display (performance, operation, product) 3. Product Acceptance: Defined Products (defined and being confirmed by the science team) Science Response JUSTIFICATION & NEEDS CONSOLIDATED PRODUCT SCIENTIFIC DEFINITION REQUIREMENTS TECHNICAL REQUIREMENTS Microwaves and Radar Institute Folie 6 3
Capabilities of TanDEM-X Cross-Track Interferometry Along-Track Interferometry New Techniques r+ Δ r r t+ Δ t t � � Digital Elevation Models 4 Phase Center MTI (traffic, …) � Large Scale Velocity Fields � � Spatial Coherence ( forest, …) (ocean currents, glacier flow, …) PolInSAR (vegetation height, …) � Double DInSAR (change maps, ..) � Moving Object Detection � Digital Beamforming (HRWS ) � High Resolution Radar Maps � Temporal Coherence Maps � Bistatic Imaging (classification, ..) TanDEM-X is a highly flexible sensor which enables multiple powerful imaging modes cross-track baselines interferometric modes bandwidth / resolution polarisations (0 km to several km) (bistatic, alternating, (0 ... 150/300 MHz) (single, dual, quad) monostatic) along-track baselines incident angles … (0 km to several 100 km) SAR modes (20° ... 55°) (ScanSAR, Stripmap, …) Microwaves and Radar Institute Folie 7 Microwaves and Radar Institute Folie 8 4
Scientific Applications Across-Track Interferometry Topography Navigation Urban areas Crisis management Glaciology Oceanography Geology Hydrology Land cover Microwaves and Radar Institute Folie 9 Along-Track Interferometry & New Techniques 64 km/h 56 km/h 68 km/h Ocean Currents Traffic Monitoring Glacier Mass Balance Transmitter Transmitter Receiver Receiver θ θ θ θ Tx Tx Rx Rx φ φ Bi-Static SAR Polarimetric InSAR Digital Beamforming InSAR Processing Super Resolution Formation Flying Microwaves and Radar Institute Folie 10 5
Single Pass X-Band InSAR Application Examples for TanDEM-X Svalex campaign 2005 over the Austfonna glacier Across-track Topography measurements Urban area campaign 2005 campaign over Munich Coherent scatterer detection (single and quad pol) New Techniques Boreal forest mapping campaign in Finland Boreal forest heights estimation and comparison Along-track 2D ocean velocity measurements + First simulation results New Techniques Microwaves and Radar Institute Folie 11 SVALEX 2005 – Svalbard Airborne Experiment Cooperation between two Institutions: 1. DLR-HR (Microwaves and Radar Institute) * Pol-InSAR measurements over land ice * penetration depth at different frequencies * retrieval of glacier topography * estimation of internal ice structures 2.AWI-Potsdam (Alfred-Wegner Institute) * measurements of optical, chemical, and physical properties of Arctic aerosols (Arctic Haze) 3.AWI-Bremerhaven (Alfred-Wegner Institute) * boundary layer meteorology * transfer of atmospheric momentum to sea ice * use of radar imagery to quantify ice ks Sensors: 1. E-SAR Radar System 2. Meteopod (wind velocity, humidity, temp.) 3. Laser Altimeter 4. KT15 (surface temp.) 5. Linescan camera Microwaves and Radar Institute Folie 12 6
Austfonna ETON (GlacierArea): Single InSAR X- band @VV Amplitude VV InSAR Phase VV InSAR Coh. VV (mean dB -8.32) (mean coh: 0.82) az rg Microwaves and Radar Institute Folie 13 Summit Area: X- band (VV) Penetration depth Frequency/ X Band VV Polarisation InSAR Coherence 0.82 Phase Difference [mean] 4.5 Penetration Depth [m] 7.7 Amplitude InSAR Coh Microwaves and Radar Institute Folie 14 7
Coherent Scatterers (CSs) Detected at X-band HH / X Band / Munich CS / HH / X Band / Munich Number of points detected ~ 95000 Near range Chirp bandwidth 100Mhz Range resolution 1.5m CSs are detected through Azimuth resolution 0.63m spectral correlation in range direction Microwaves and Radar Institute Folie 15 Polarimetric SAR X Band for CS’s Detection Detection of Coherent R: HH Points G: HV B: VV PI-SAR X-band Test Site: Gifu, Japan Courtesy for the provision of X Band data: Hiroshi Kimura Microwaves and Radar Institute Folie 16 8
X Band Single-Pass Dual Baseline Interferometry Test Site: Oberpfaffenhofen Amplitude Image – X-band Interferometric Phase – Baseline 1 Interferometric Phase – Baseline 2 Interferometric Coherence - Baseline 1 Interferometric Coherence - Baseline 2 Microwaves and Radar Institute Folie 17 X Band Single-Pass Dual Baseline Interferometry E-SAR / Test Site: Oberpfaffenhofen Amplitude Image – X-band Interferometric Coherence - Baseline 1 Interferometric Coherence - Baseline 2 Microwaves and Radar Institute Folie 18 9
X Band Single-Pass Interferometry Boreal forest height inversion E-SAR / Test Site: Helsinki, Finland 0 0 Forest Height estimated at X-band & HUTSCAT Height Profiles Microwaves and Radar Institute Folie 19 2-D Current Measurements with TanDEM-X Squinted Split Antenna Mode Proposal by IMF to use Tandem-X in a squinted split antenna mode configuration for 2-D current measurements Simulated Tandem-X Measurement Ocean Eddie Courtesy: IMF Johannes Schulz-Stellenfleth Microwaves and Radar Institute Folie 20 10
Summary: Science Exploitation Science TanDEM-X will provide novel DEM quality fully compliant to a variety of different scientific applications with global access. TanDEM-X will demonstrate new SAR techniques in space for the development of future SAR systems. TanDEM-X will deliver two main categories of products (DEM & RDP) TanDEM-X mission is an evolution capitalizing on technology and experience from SRTM and TerraSAR-X. TanDEM-X is a unique system accounting for scientific (ongoing development), technical (experimental) and commercial (operational) demands. Microwaves and Radar Institute Folie 21 Next X-band Satellite Mission Microwaves and Radar Institute Folie 22 11
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