DEM products from TerraSAR-X & TanDEM-X

Nora Meyer zu Erpen // 25.01.2011

Date - 2

GEO-Information Services within Astrium and EADS

* France, Germany, UK, Spain, Netherlands

Airbus Eurocopter CassidianAstrium

Turnover 2009: € 4.8 billionStaff 2009: 15,000*

Space TransportationAstrium Satellites

GEO-InformationTelecommunications Secure Satcom Systems Navigation

Astrium Services

Date - 3

GEO-Information Services: Key Facts & Figures

Spot Image Corporation

Spot Image Brasil

Spot Imaging

Services

Spot Asia

BeijingSpot Image Tokyo

Spot Image

InfoterraSpain

Spot Image

Infoterra UK

InfoterraGermany

InfoterraHungary

Spot InfoterraHellas Infoterra AP

� Staff: +900, located in 12 countries

� Combining the talent and capabilities of Spot Image and Infoterra teams,integrated within the GEO-Information division of Astrium Services

� An international networkof partners & customers

Date - 4

Key Assets & Skills

EO data acquisition(spaceborne, airborne &

field data)

Data processing

Consultancy, training & know-how transfer

Geo-information services

Covering the whole value-chain

Data management & data access

Date - 5

TerraSAR-Programm

� TerraSAR-X Mission

� Successful launch 15.06.2007

� Resolution up to 1m

� Geometric accuracy unrivalled by any other commercialspaceborne sensor today

� Weather and sun inclination independent data acquisitionworldwide

� Unique agility (rapid switches between imaging modes and polarisation)

� Public Private Partnership (DLR, EADS Astrium)

Date - 6

TerraSAR-Programm

TerraSAR-X add-on for Digital Elevation Measurement (DEM)

� Twin Satellite Constellation: TerraSAR-X & TanDEM-X

� Launch satellite: 21.06.2010

� TanDEM-Mission start (twin constellation): 12.12.2010

� Primary Mission Goal: homogeneous, high-quality global DEM using interferometry

� Unprecedented accuracy, coverage & quality

� Consistent, seamless coverage of the Earth’s land surface within ~ 3 years

� Public-Private Partnership (DLR / Astrium)

� TanDEM-X Mission

Date - 7

TerraSAR Missions

� Public Private Partnership (PPP)

•Development of satellite operating system•Development of the ground segment for data reception•Data procession, archiving, calibration and distribution (non-commercial)

•Development & assembly of the satellite•Satellite launch•Development of a commercial service system

•Commercialization of the TerraSAR-X/ TanDEM-X data & products

Date - 8

TerraSAR-X: Technical data

15.06.2007 (Baikonur, Kasachstan)Launch

514kmOrbit height

97,44 degree (sun-synchronous orbit)Inclination

Approx. 1.230kgSatellite mass (start)

SpotLight (HR): >= 1m (scene size: 5 to 10km x 5km)

SpotLight: >= 2m (scene size: 10km x 10km)

StripMap: 3 m (scene size: 30km x 50km)

ScanSAR: 18m (scene size: 100km x 150km)

Resolution

9,65 GHz (Frequency band: X-Band)Radar frequency

At least 5 yearsOperational life

800 watt (Average)Energy consumption

5m height by 2,4m diameterSatellite size

DLR/ Astrium (D)Agency

TerraSAR-XMission

Date - 9

9

Radargrammetry SAR Interferometry

(Stereo 3D reconstruction) (repeat pass InSAR: 11 days)

(single pass InSAR: simultaneous)

Utilization of two images with different acquisition geometry (intensity only) ���� less accurate than InSAR

Utilization of the phase difference of two images with the same geometry� more accurate, where feasible

Digital Elevation Information: Methods

Date - 10

InSAR

(single pass)

Advantage to repeat pass:Simultaneous data acq.: no temporal decorrelation (no changes in reflection characteristics, no atmospheric changes)

� very high vertical accuracy

-Based on phase information- two acquisitions from almost the same orbit position

TanDEM-X

InSAR is sensitive to temporal decorrelation:a) surface reflection characteristics may change between the two acquisition datesb) strong sensitivity to atmospheric changes

�11days minimum separation between acq. dates

-Based on phase information- two acquisitions from almost the same orbit position

InSAR

(repeat pass)

-RDG is robust to changes on earth surface-RDG is independent from atmospheric circumstances and changes -difference between acquisition dates < 11 days

-Based on amplitude data-two acquisitions with different acquisition angles (steep & flat � stereo pair)

RadargrammetryTerraSAR-X

CommentsDescriptionMethodMission

Digital Elevation Information: Methods

Date - 11

InSAR

One area is covered:two times from almost parallel orbit

positions•Repeat pass: TerraSAR-X•(Single pass: TanDEM- Mission)

• Elevation information is derived from the difference distance from one ground point to each satellite position

Date - 12

One area is covered:

• two acquisitions with different acquisition angles (steep & flat � stereo pair)• ~ 20°disparity angle

Radargrammetry

Date - 13

13

Data acquisition & DSM extraction:

ascending descendingRadargrammetry

� acquisition of at least one TS-X stereo-pair images

� From both looking directions (ascending & descending)

� Merge of ascending & descending DSM (Mean value approach)

Reduce influence of layover & shadow effects:

Date - 14

TerraSAR-X:

Radargrammetry-DEM Products

Date - 15

Digital Elevation Models (DEM)

TerraSAR-X Elevation DSM (Radargrammetry):

� Sensor: Independent of weather conditions

� Continuous representation of earth surface

(no data gaps based on clouds)

DSM – Digital Surface ModelDTM – Digital Terrain Model

� Frequency band: X-Band (9,5 GHz)

� DSM (Digital Surface Model): All objects (trees, houses etc.) are included in this model. It represents the surface as we observe it from above (e.g. from an airplane).

Date - 16

16

Digital Terrain Model (based on DEM level 2)

Processing DSM data to bare earth

� Not operational yet (expected product release 03/2011)

DEM level 3

(TerraSAR-X Elevation DTM)

Digital Surface Model, hydro enforced version (based on DEM level1)

Implementation of specified hydro network, airstrips

DEM level 2

(TerraSAR-X Elevation DSM)

Digital Surface Model, basic version

Artefact removal

DEM level 1

(TerraSAR-X Elevation DSM basic)

Digital Surface Model (raw-DSM as output from the radargrammetry processor)

DEM level 0

(raw-DSM)

Editing Description Product

Product variant overview:

TerraSAR-X Elevation DEM products

Date - 17

17

Auxiliary Layer of TS-X Stereo DEM:

TerraSAR-X Elevation DEM products

1-bit GeoTIFFXXXEditing mask

ESRI shapeXContour lines

1-bit GeoTIFFXXWater body mask

4-bit GeoTIFFXXXFilling mask

1-bit GeoTIFFXXXInterpolation mask

8-bit GeoTIFFXXXHeight Error mask

1-bit GeoTIFFXXXVoid mask

ESRI shapeXXXShadow & Layover mask

ESRI shapeXXXSource mask

FormatDEM_3DEM_2DEM_1Product / Package

• Output from radargrammetry processor

• Results from DEM editing

Date - 18

TerraSAR-X Elevation DEM products

Date - 19

19

Validation & Verification Approach

Qualitative approach: visual / descriptive

DEM QA process

Bogor shaded Relief

Qua

Shaded relief:

TSX-Stereo DSM

100

150

200

250

300

350

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73

Hei

ght [

m]

ICESat Points SRTM Radargrammetry DSM Zinfo

Profil plot:

Quantitative approach: statistic

���� absolute vertical error (expressed in RMSE / LE90)

Date - 20

TerraSAR-X Elevation DSM

Metadata in XML-Format (ISO 19115 compliant ���� Next release)Auxiliary Metadata

UTM projection; UPS projection for polar regions.Horizontal ref. datum WGS84, Vertical ref. datum EG M96

Projection Information

MeterVertical Unit

32-bit GeoTiffData Format

A minimum of 500 km² per orderArea of interest

5 - 10 m (90% circular error) depending on terrainHorizontal accuracy

5 - 10 m (point to point within 100 x 100 km, 90% li near error)Relative vertical accuracy

5 - 10 m (90% linear error) depending on terrainAbsolute vertical accuracy

10 m Grid Spacing

Radargrammetry based on TerraSAR-X StripMap stereo p airsMethod

Product specification:

Date - 21

ISO 19115 xml

Metadata htmlstylesheet

Components of metadata

Date - 22

22

Alpine/Ice/Snow:Wallis (CH)

Mountainous-Flat:Eifel (DE)

Tropical Forest:Kalimantan (IND)

Mediterranean:Marseille (FR)

Tropical Forest:Montserrat

Desert:Oman

Mountainous:Black Forest & Aulendorf (DE)

Mountainous:Solothurn (CH)

Flat:El Manteco (VEN)

Tropical Forest:Malaysia

Reference: high quality DEM (LIDAR, aerial photograph s)

Reference: GPS point samples

Tropical Forest:Sabang (IND)

Alpine / Ice Snow:Juneau (USA)

Dry area:Ft. Irvin (USA)

Urban:Johannesburg (ZA)

Mountainous:Yutan

Verification & Validation Sites

DSM verification & validation

Test sites:

Evaluation based on a variety of test areas and reference data

Date - 23

TanDEM-X: Digital Elevation Models

Date - 24

Nominal Data Acquisition 3 (+?) Years

2010 2011 2012 2013 2014

1 global DEM acquisition with small baselines

1 year1 year

1 global DEM acquisition with larger baselines

1 year1 year

DEM data takes for difficult terrain

with different viewing

geometry

6 months6 months

Customized DEMs

with large interfero-

metric baselines

≥≥ 3 months3 months

Com

missioning P

hase

5 months5 months

Production TDX_IDEM TDX_DEM

2014

DEM Availability TDX_IDEM TDX_DEM

Global DEM: Data Acquisition Plan

Date - 25

� TanDEM-X intermediate DEM�Only one coverage available�Errors and voids expected in mountainous regions�Available also with reduced pixel spacing (factor 2 & 4)

� TanDEM-X DEM - Final DEM Product of the TanDEM-X Mission�Two complete coverages of the earth plus additional acquisitions for difficult terrain �Accuracy according to HRTI-3�Available also with reduced pixel spacing (factor 2 & 4)

� DEMs on special user-request�Accuracy according to HRTI-4, only for local size regions

Global DEM: Product overview

Date - 26

SRTM / X-SAR

� Standards for Digital Elevation Models (DEM)DEMs Spatial Resolution Absolute Vertical Accuracy (90%)

Relative Vertical Accuracy(point-to-point in 1°cell, 90%)

DTED-1 90 m x 90 m < 30 m < 20 m

DTED-2 30 m x 30 m < 18 m < 12 m

12 m x 12 m < 10 m < 2 m

6 m x 6 m < 5 m < 0.8 m

HRTI-3

HRTI-4

Global DEM: Specification

Date - 27

TanDEM-X DEM data

Mount Aetna, Italy

Date - 28

TanDEM-X DEM data

Salar de Uyuni, Bolivia

Date - 29

TerraSAR-X2 – next step in service continuity

� Service continuity, sustainability� TanDEM-X as a bridge� constellation enabled

� New “commercial” business model� Public Private Partnership

TerraSAR-X / TanDEM-X� Commercial mission

TerraSAR-X2

� TerrSAR-X2 mission specifics� Market driven (service definition)� Service Subscription , Partnerships� Coordinated sharing of excess

collect capacities

TerraSAR-X2 will provide service continuity in the family of sustainable, reliable series of high quality SAR satellites

‘08 ‘10 ‘12 ‘14 ‘16 ‘18 ‘20 ‘22 ‘24

TDX PPP

TSX1 PPP

PAZ Hisdesat

TSX2 Infoterra

TSX3 PPP

Date - 30

Vielen Dank für Ihre Aufmerksamkeit

Astrium Services Geo-Information - Infoterra GmbHPlatz der Einheit 14

14467 Potsdam

T: +49 331 237484-03 / F: +49 331 237484-27

nora.meyer.zu.erpen@astrium.eads.netwww.infoterra.de

Nora Meyer zu Erpen