This document discusses using multistatic radar configurations to improve synthetic aperture radar (SAR) tomography performance. It presents using multiple transmit-receive sensor pairs, which act as additional equivalent sensors, to obtain improved range resolution compared to monostatic acquisitions. The document evaluates this approach using real data and demonstrates enhanced tomographic reconstruction of distributed scatterers. It concludes that fully sampled multi-input multi-output acquisitions could significantly reduce the time required for SAR tomography measurements of snowpacks.

1. SAPHIR
Improving SAR tomography performance
using
efficient antenna configuration
Laurent Ferro-Famil(1,2), D. Cristallini(3), D. Pastina(3), P. Lombardo(3)
(1)
IETR, University of Rennes 1, France
(2)
University of Tromso, Dpt. Of Physics and Technology, Norway
(3)
University of Rome “La sapienza”, INFOCOM Dpt, Italy

2. SAPHIR
Outline
Multistatic radar constellation for improved range resolution
Extension to Multi-Baseline SAR tomography
Assessment from real data and need for MIMO acquisitions

3. SAPHIR
Principle using monostatic sensors
Single acquisition
• Ground range resolution
●
Equivalent beam aperture
Two acquisitions
• Max diversity for contiguous apertures
●
Combined range resolution

4. SAPHIR
Principle using multistatic sensors
MIMO acquisition
• 2 Tx-Rx sensors
• Orthogonal signals
• 3rd equivalent sensor
• Max resolution

5. SAPHIR
Outline
Multistatic radar constellation for improved range resolution
Extension to Multi-Baseline SAR tomography
Assessment from real data and need for MIMO acquisitions

6. SAPHIR
Monostatic inSAR configuration
Monostatic acquisition
MIMO acquisition: additional equivalent sensor
S'2

7. SAPHIR
MIMO TOMSAR geometrical configuration

8. SAPHIR
MIMO TOMSAR geometrical configuration

9. SAPHIR
Tomographic response: coherent scatterer
Improved resolution x 2 Improved ambiguity x 2
Coherent scatterer: arbitrary improvement factor

10. SAPHIR
Tomographic response: distributed scatterer
For a randomly rough surface

11. SAPHIR
Tomographic response: distributed scatterer
fz(z) f(z)
Spread
See: Tebaldini and Rocca, IGARSS 2010

12. SAPHIR
Tomographic response: high res system`
BEAMFORMER
Improved resolution x 2 Improved ambiguity x 2

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Tomographic response: high res system
CAPON
Unchanged high resolution Improved ambiguity x 2

14. SAPHIR
Tomographic response: medium res system
BEAMFORMER
SLIGHTLY Improved resolution x 2 Improved ambiguity x 2

15. SAPHIR
Tomographic response: medium res system
CAPON
Unchanged high resolution Improved ambiguity x 2

16. SAPHIR
Outline
Multistatic radar constellation for improved range resolution
Extension to Multi-Baseline SAR tomography
Assessment from real data and need for MIMO acquisitions

17. SAPHIR
Application to real data

18. SAPHIR
Application to real data
Full resolution
75% resolution
75% sampling

19. SAPHIR
Need for MIMO acquisitions: GB-TOMSAR
Tomographic measurements of a snow pack at X and Ku band

20. SAPHIR
Need for MIMO acquisitions: GB-TOMSAR

21. SAPHIR
Need for MIMO acquisitions: GB-TOMSAR
- resolution + ambiguity: 8-10 images
- near range measurements: az sampling
Hours of acquisition
4-port system → time / 5