DLR's Airborne F-SAR System Andreas Reigber Microwaves and Radar - - PowerPoint PPT Presentation

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DLR's Airborne F-SAR System Andreas Reigber Microwaves and Radar - - PowerPoint PPT Presentation

Apr 18, 2023 448 likes •819 views

DLR's Airborne F-SAR System Andreas Reigber Microwaves and Radar Institute Why Airborne SAR? Advantages of airborne SAR: Airborne SAR Higher SNR & resolution than spaceborne sensors Flexible operation of the sensor

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DLR's Airborne F-SAR System

Andreas Reigber Microwaves and Radar Institute

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SLIDE 2

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Why Airborne SAR?

Advantages of airborne SAR:

  • Higher SNR & resolution than spaceborne

sensors

  • Flexible operation of the sensor
  • Experimental platform for new technology

For the Institute:

  • Defining the „state‐of‐the‐art“ in SAR sensor

technology

  • Prepare future satellite missions
  • Test and develop new signal processing

algorithms

  • Development and demonstration of new

products and imaging techniques

  • Execution of scientific flight campaigns

development & demonstration of new technology demonstration of new techniques with existing spaceborne systems concepts for future spaceborne systems

Airborne‐SAR

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SLIDE 3

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P-band C-band X-band L-band

The Advanced Airborne Sensor F‐SAR

F-SAR technical characteristics X C S L P RF [GHz] 9.6 5.3 3.2 1.3 0.35 BW [MHz] 800 400 300 150 100 PRF [kHz] up to 12 Rg res. [m] 0.2 0.4 0.5 1.0 1.5 Az res. [m] 0.2 0.3 0.35 0.4 1.5 PolSAR ✓ ✓ ✓ ✓ ✓ Rg cov [km] 12.5 (at max.bandwith) Sampling 8 Bit real; 1000MHz; 4 channels.

Remarkable features: ‐ Very high resolution and SNR ‐ Multispectral operation (up to 4 bands) ‐ Polarimetry in all bands ‐ Single‐pass interferometry at X and S‐band ‐ Modular sensor design

Main Goals:

  • Defining the „state‐of‐the‐art“

in SAR sensor technology

  • Scientific flight campaigns, preparation of

new satellite missions

  • New approaches by multispectral & high

resolution PolSAR imaging

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SLIDE 4

Slide 4

DLR’s New F‐SAR Sensor

F‐SAR core modules X‐band rack C/S‐band rack L‐band rack P‐band rack

R1 R2 1 2 XCS-Band UPC E4 XCS Chirp E4 X-Band Antenna Switch E2a

1H 1V 2H 2V 3H 3V 1H 1V 2H 2V

S-Band Antenna Switch D3u, D3o C-Band Antenna Sw. D4

1H 1V

ADC ADC1 C5 ADC ADC2 C5 L-Band Antenna Sw. F3

1H 1V

P-Band Antenna Sw. A3

1H 1V

ADC ADC5 C5 ADC ADC6 C5 Disk Array 1 B2 Disk Array 2 B2 System Control B4 Onboard Processor C7 STC/AGC Processor C5 Timing Unit C6

DC/AC Power Supply

C1 Navigation & Flight Guidance System C2 S1,2 S1 S2

X1H X1V X2H X2V X3H X3V S1H S1V S2H S2V C1H C1V L1H L1V P1H P1V R1X R2X R1S R2S R1C R2C

R5 R6

R1L R2L R1P R2P

L-Band UPC F5 L Chirp F5 S1 S2 S1 P Chirp A5 X-Band TWTA E1 SC TWTA D1 XCS Down Converter E3 L-Band HPA F1 P-Band HPA A1

F5 L-Band Down Conv. A5 P-Band Down Conv. 2 of 4 Switch C6

MDR MDR1 C3 MDR MDR2 C3 MDR MDR5 C3 MDR MDR6 C3 3 4 5 6 7 8

SC Ant. Sw.

D2 Monitor Bus

F-SAR Basic Configuration (Rack B and Rack C) X-Band Rack E SC-Band Rack D

P-Band UPC A5

P-Band Rack A L-Band Rack F

modular cabin layout F‐SAR system layout

The Advanced Airborne Sensor F‐SAR

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SLIDE 5

F‐SAR „in action“ (mounted on research plane Do228)

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Slide 6

Kaufbeuren (Germany)

TerraSAR‐X, X‐band VV, HRS mode

1.0m x 2.0m resolution

Kaufbeuren (Germany)

F‐SAR, X‐band, VV polarisation 0.25m x 0.25m resolution

Kaufbeuren (Germany)

F‐SAR, X‐band quadpol (HH, VV, HV) 0.25m x 0.25m resolution

Simulation of Future Spaceborne Products

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Slide 7

Oensingen (Switzerland)

F‐SAR, S‐Band quadpol (HH, HV, VV) 0.5m x 0.65m resolution, 5 looks

Simulation of Future Spaceborne Products

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Real‐time Situation Monitoring

F‐SAR (DLR‐HR) data downlink: 1.25 GBit/sec (DLR‐KN) laser / microwave Data distribution to end‐users (BOS, THW, red cross) through central platform real‐time onboard processing weather independent day & night capability

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Real-time Situation Monitoring

Real‐time Situation Monitoring

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InSAR: Generation of digital elevation models

Kaufbeuren (Germany)

Tandem‐X Digital Surface Model

Kaufbeuren (Germany)

F‐SAR Digital Surface Model

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Muriel InSAR: Generation of digital elevation models

INSARDEM XS (Scale around: 41m) ALS 26032013 (Scale around: 41m) Difference [-1m,1m]

InSAR DEM Laser DEM Difference Easting Northing 4 ‐4 4 Laser DEM

InSARDEM (Scale around: 41m)

  • 2

2 Laser (Scale around: 41m)

  • 2

2

InSAR DEM Laser DEM 2 ‐2 2 ‐2 µ = ‐0.15m σ = 0.11m Difference Easting Northing

INSARDEM XS (Scale around: 41m)

  • 4

4 ALS 26032013 (Scale around: 41m)

  • 4

4

InSAR DEM Laser DEM 4 ‐4 4 ‐4 µ = 0.21m σ = 0.22m

Testsite: Jade Bight

F‐SAR Digital Surface Model

  • vs. ALS Reference Heights
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Slide 12

DInSAR: Measurement of Ground Deformation / Motion

SWISAR campaign (2006 & 2007)

Hamm (Germany) deformation within 6 months

DINSAR campaign (2009)

Aletsch glacier (Switzerland) 1‐day ice motion

85 cm / day 20-40 cm / year

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RGB = L/X/P-Band Estimated Forest Height

Polarimetric Interferometry: Estimation of Forest Height and Biomass

Azimut

L-band HH

Courtesy of K. Papathanssiou

y z x n r

bl

h

      

VV VH HV HH

S S S S S] [ 1       

VV VH HV HH

S S S S S ] [ 2

1 2

PolInSAR

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SLIDE 14

Fichtelgebirge / Germany Corridor / Spain Bayrischer Wald / Germany Traunstein / Germany Oberpfaffenhofen / Germany

Courtesy of

Polarimetric Interferometry: Estimation of Forest Height and Biomass

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Slide 15

3D SAR Tomography

  • Innovative method for3D‐imaging
  • Possible applications:
  • Vegetation structure, biomass
  • 3D City models
  • Archeology

y z x

N parallel tracks (ca. 5‐20) n r L Hn

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Slide 16

Circular SAR Imaging

360° illumination

r ≈ 6km

antenna illumination x y z

  • Possibility of extremly high resolution

(up to λ/4, i.e. about 6cm at L‐band)

  • Possibility of “holographic” 3D imaging
  • Possibility of continous imaging (“video SAR”)

Circular SAR Stripmap SAR

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C‐Band X‐Band

Circular SAR Imaging: Continuous Monitoring

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Polarimetric P-band Sounding

  • Dedicated imaging mode for deep sounding of ice / bedrock structure
  • Long wavelength can penetrate very deep in dry (i.e. cold) ice.
  • Identical antennas as in SAR mode, but nadir‐looking by modified feed network.

clutter clutter? bedrock

HV polarisation (single acquisition, low altitude)

32 km

~ 570m

Spitzbergen (Nordaustlandet)

Sounder Image, P‐Band 350MHz

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SLIDE 19

Holographic Ice Sounding / Multi-circular SAR

L‐Band P‐Band

Kangerlussuaq / K‐Transect

Fully polarimetric HoloSAR images. Pauli decomposition R,G,B = HH‐VV, HV, HH+VV.

ARCTIC15

F‐SAR CAMPAIGN April ‐ May 2015

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Slide 20

space-/airborne bistatic geometry

v=7km/s v=85m/s

Bistatic SAR Imaging & Processing

TerraSAR-X (Tx) F-SAR (Rx) bistatic image azimuth resolution 0.5m

  • Development of synchronisation techniques

in preparation of TanDEM‐X

  • Development of new processing concepts

(BFFB ‐ bistatic fast factorised back‐projection)

v=7000m/s v=85m/s

monostatic bistatic monostatic bistatic

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Slide 21

Agriculture (crop parameters, soil moisture)

Airborne‐SAR Campaigns (since 2001)

Forestry (forest heights and biomass) Surveys over sea and land ice Sea topography and oceanography ?

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Mission Proposal for Environment and Climate:

Advanced high‐performance SAR‐Technology:

  • Fo

Format ation fligh flight wi with tw two SAR SAR‐sa satellit llites

  • Polarim

larimetric tric in interf rferometry ry and and to tomo mography

  • Di

Digi gital Beam Beamform rming wi with lar large refle flect ctor an antenna nna

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SLIDE 23
  • 11 test‐sites in Greenland
  • Analysis of several novel methods

for the estimation of snow and ice parameters

  • Evaluation of high‐resolution SAR for

security applications in Arctic environments

  • Study of the stongly varying penetration

capabilities of the different bands into snow and ice

  • Demonstration of multi‐spectral SAR

data recording in 4 frequency bands

  • Acquisition of unique data sets

for further research

F‐SAR Campaign ARCTIC/DALOX (May 2015)

Campaign test sites

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SLIDE 24

ARCTIC15

Helheim Glacier, differences in L‐, S‐ and X‐ band.

Fully polarimetric images. Pauli decomposition R,G,B = HH‐VV, HV, HH+VV. F‐SAR CAMPAIGN April ‐ May 2015

X‐Band L‐Band S‐Band

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SLIDE 25

ARCTIC15

Helheim Glacier, differences in L‐, S‐ and X‐ band.

Fully polarimetric images. Pauli decomposition R,G,B = HH‐VV, HV, HH+VV. F‐SAR CAMPAIGN April ‐ May 2015

X‐Band L‐Band S‐Band

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SLIDE 26

Increasing penetration depth X‐Band C‐Band L‐Band P‐Band (non‐simultaneous)

ARCTIC15

K‐Transect ‐ Percolation zone

Fully polarimetric images. Pauli decomposition R,G,B = HH‐VV, HV, HH+VV. F‐SAR CAMPAIGN April ‐ May 2015

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SLIDE 27

ARCTIC15

Sea Ice between Greenland and North America

Fully polarimetric images. Pauli decomposition R,G,B = HH‐VV, HV, HH+VV. F‐SAR CAMPAIGN April ‐ May 2015

L‐Band S‐Band X‐Band

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SLIDE 28

ARCTIC15

Godhavn, X‐band detail image, 25cm resolution

Fully polarimetric images. Pauli decomposition R,G,B = HH‐VV, HV, HH+VV. F‐SAR CAMPAIGN April ‐ May 2015

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BIOMASS: ESA Earth Explorer Mission

System:

 Fully-polarimetric P-band SAR  12 m reflector antenna  Strip-map acquisition mode with 6 MHz bandwidth  Spatial resolution: 60 x 50 m with 6 ENL  Launch planned for 2021

ESA EE-7 to map forest above-ground biomass and its changes

PolSAR Pol-InSAR Combined TomoSAR

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AfriSAR Campaign 2016

Goals:

  • Preparation of ESA‘s BIOMASS mission
  • Algorithm development for Tandem‐L
  • Various test‐sites in Gabun (tropical rain forest)
  • Cooperation with ESA, NASA/JPL, NASA/Goddard, Onera
  • Extensive ground‐truthing

Execution:

  • Flight campaign by Onera in July 2015
  • F‐SAR campaign in February / March 2016
  • Parallele flights by UAVSAR and LVIS in March 2016

Results:

  • SAR acquisitions in L‐ and P‐band quadpol
  • Reflectivity, PolInSAR, Tomography
  • Simulation of BIOMASS products
  • Estimation of forest heights and biomass
  • Evalutation and development of BIOMASS

and Tandem‐L algorithms

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AfriSAR Kampagne: Kalibrierung

L-Band P-Band Nkok calibration test site

(0°22'43.34"N, 9°36'30.80"E) surface double volume

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AfriSAR Campaign: Results

Pongara test site: mangroves

(0° 9'15.29"N, 9°28'46.56"E)

L‐Band P‐Band

surface double volume

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SLIDE 33

AfriSAR Campaign: P-Band Mosaic (7 tracks)

P-Band

surface double volume

Lopé test site: rain forest / savannah

(0°12'41.06"S, 11°33'11.58"E)

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Current Developments: Digital Beamforming (DBF) Extension

Future Requirements imaging mode (quad pol) Mode X Mode Y Mode Z Resolution 5 m 1 m << 1 m Swath 400 km 100 km 30 km Orbit Duty Cycle 30 Minutes per Orbit

Modus Y Modus Z ModusX A D

Digital Beam Forming

A D A D A D A D

SAR Processing

x x x x x

A D

1 2 a1 3 4 5 a2 a3 a4 a5

SAR Processing

x

Mixing

radar with phased array radar with DBF Possibilities:

  • Better radiometric accuracy
  • Moving target detection
  • Ambiguity suppression
  • RFI suppression
  • Adaptive & hybrid SAR imaging

modes

  • …
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F‐SAR: Next Steps…

F-SAR digital system X-band rack C/S L P

F‐SAR DBFSAR

DBF digital system DBF X-band rack

F‐SAR: 2+2 Kanäle à 500MHz DBFSAR: 12 Kanäle à 2 GHz Maximum data rate DBFSAR: 8.5 GByte /sec (Factor 12 to F‐SAR)

Ka-band rack

DBF‐SAR: First X‐band in‐flight results (April 2017)