Содержание
- 2. Outline Raw SAR image characteristics Algorithm basics Range compression Range cell migration correction Azimuth compression Motion
- 3. Airborne SAR real-time IFP block diagram Image-Formation Processor New terminology: Presum (a.k.a. coherent integration) Corner-turning memory
- 4. Basic SAR image formation processes
- 5. Basic SAR image formation processes
- 6. Basic SAR image formation processes
- 7. Basic SAR image formation processes
- 8. Basic SAR image formation processes
- 9. Optical image-formation processing
- 10. Demodulated baseband SAR signal [from Digital processing of synthetic aperture radar data, by Cumming and Wong,
- 11. Demodulated baseband SAR signal includes R-4 and target RCS factors Vr : effective radar velocity (a
- 12. SAR signal spectrum [from Digital processing of synthetic aperture radar data, by Cumming and Wong, 2005]
- 13. SAR signal spectrum Also fτ : range frequency, Hz, where –Fr /2 ≤ fτ ≤ Fr
- 14. SAR signal spectrum envelope of the radar data’s range spectrum antenna’s beam pattern envelope in Doppler
- 15. Matched filter processing Given an understanding of the characteristics of the ideal SAR signal, an ideal
- 16. Range Doppler domain spectrum [from Digital processing of synthetic aperture radar data, by Cumming and Wong,
- 17. Range migration
- 18. Range-dependent range migration Baz : azimuth bandwidth Br : transmitted pulse bandwidth ηo : azimuth time
- 19. Range-Doppler processing
- 20. Range-Doppler processing
- 21. Range-Doppler processing
- 22. Range-Doppler algorithm RCMC: range cell migration compensation SRC: secondary range compression Range cell migration compensation (RCMC)
- 23. Range-cell migration compensation Part of the migration compensation requires a re-sampling of the range-compressed pulse using
- 24. Chirp scaling algorithm The range-Doppler algorithm was the first digital algorithm developed for civilian satellite SAR
- 25. Chirp scaling algorithm
- 26. Chirp scaling algorithm
- 27. Chirp scaling algorithm
- 28. Chirp scaling algorithm
- 29. Chirp scaling algorithm
- 30. Range-cell migration compensation
- 31. Omega-K algorithm (WKA) The chirp-scaling algorithm assumes a specific form of the SAR signal in the
- 32. Omega-K algorithm (WKA) Illustration of the range/azimuth cross coupling using the raw phase history from a
- 33. Omega-K algorithm (WKA)
- 34. Stolt interpolation
- 35. Stolt interpolation
- 36. Stolt interpolation
- 37. Comparison of IFP algorithms Azim MF: azimuth matched filter Hyperb: hyperbolic P.S.: power series, i.e., parabolic
- 38. Motion compensation Imperfect trajectories during SAR data collection will distort the data set resulting in degraded
- 39. Motion compensation To provide position and attitude knowledge various instruments are used Gyroscopes (mechanical or ring-laser)
- 40. Motion compensation
- 41. Motion compensation In addition to position and attitude knowledge acquired from various external sensors and systems,
- 42. Autofocus Just as non-ideal motion corrupts the SAR’s phase history, the received signal can also reveal
- 43. Quadratic phase errors
- 44. High-frequency phase errors
- 45. Autofocus – inverse filtering
- 46. Autofocus – inverse filtering
- 47. Autofocus – phase gradient The phase gradient autofocus algorithm is unique in that it is not
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