Fig. 1. Schematic diagram of SAL principle

Fig. 2. Schematic diagram of FMCW Ladar

Fig. 3. The SAL system and imaging result of Naval Research Laboratory^[21]. (a) Experimental system; (b) Imaging result

Fig. 4. The SAL system and imaging result of Aerospace Corporation^[37]. (a) Experimental system; (b) Imaging result

Fig. 5. The SAL system with large aperture in Shanghai Institute of Optics and Fine Mechanics, CAS^[42]

Fig. 6. FMCW-SAL system based on electro-optical modulation^[44]

Fig. 7. Schematic diagram of phase-code ladar

Fig. 8. The phase-code SAL system in shanghai Institute of Optics and Fine Mechanics, CAS^[54]

Fig. 9. The phase-code SAL system in Institute of Optics and Electronics, CAS^[59]

Fig. 10. Experimental results of PGMA algorithm^[67]. (a) Photography of the target; (b) Image formatted by ordinary FFT; (c) Image autofocused by PGA; (d) Image autofocused by PGMA

Fig. 11. The experimental results of micro-vibration error compensation^[45]. (a) Photography of the satellite model; Image formatted (b) Without phase error compensation; (c) By method using PGA algorithm; (d) By using the proposed algorithm

Fig. 12. Schematic diagram of self-interferometer SAL^[77]

Fig. 13. Geometric model of SAL system based on interferometer processing^[79]

Fig. 14. Orthogonal interferometer ISAL imaging experiment based on time-frequency analysis^[81]. (a) Geometric model of imaging; (b) Photography of the target; (c) Image without compensation; (d) Image with compensation

Fig. 15. Correction and compensation effect of TRC and LORC^[85]. (a) Photo of the target; (b) Range-doppler domain imaging results before correction; (c) Range-doppler domain imaging results after TRC correction; (d) Range-doppler domain imaging results after TRC correction and LORC compensation

Fig. 16. Measured and compensated results for laser phase noise^[90]. (a) Comparison of the measured and theoretical values for the phase of the heterodyne signal; (b) The estimation results of the laser phase noise; (c) The compensation results with Gaussian linewidth; (d) The compensation results with Lorentz linewidth

Fig. 17. Simulation comparison results of RDA and MMBIR algorithm under different CNRs^[95]. (a) 5 dB; (b) 0 dB; (c) −5 dB. The red dash area is the detail part of the images

Fig. 18. Airborne SAL experimental results of Lockheed Martin Coherent Technologies^[52]. (a) Experimental system; (b) Imaging results

Fig. 19. Airborne SAL experiment in shanghai institute of optics and fine mechanics^[98]. (a) Experiment scene; (b) The photograph of target; (c) Imaging result

Fig. 20. Airborne SAL experiment in institute of electronics^[48]. (a) Experimental scene; (b) Photograph of target; (c) Imaging result

Fig. 21. Array SAL experiment in Institute of Electronics^[96]. (a) Photograph of the target; (b) Imaging results of four channels; (c) The whole imaging result; (d) The electronic system; (e) The optical system

Fig. 22. Outdoor experimental scene and result at 1.1 km away^[109]. (a) Schematic diagram of ISAL system; (b) Photography of the transceiver; (c) Photography of the target; (d) Imaging result

Fig. 23. Outdoor experimental result at 6.9 km away^[95]. (a) Photography of the target; (b) Images recovered by RDA; (c) Images recovered by MMBIR