Research On Signal Processing Of Interferometric Synthetic Aperture Radar And Phase Unwrapping Algorithm

Interferometric Synthetic Aperture Radar is a technology that combines SAR imaging and interferometry. According to radar system parameters, posture and orbit parameters, this technology can establish the geometrical relationship between height information of ground surface and the above parameters. So the ground surface elevation can be measured quickly and widely. At present, InSAR has got successful application in many areas, and become one of important research contents in remote sensing field。In signal processing of InSAR, some operations, such as co-registration, filtering, generation of interferogram, flatten, phase unwrapping, elevation of inversion, are needed, so as to the three-dimensional coordinates of the target areas can be get. However, the signal processing above is complex. In order to get three-dimensional information precisely, it is significant to study how to complete the signal processing efficiently, fleetly and accurately.In this paper, SAR imaging geometry was studied firstly. The characteristic of signal emission and reception and imaging mechanism were analyzied. Particularly, the imaging procession of airborne SAR was studied, and imaging simulation of point targets was realized by different algorithms. Because what the SAR received is the backscatter echos of target object, so understanding the backscattering mechanism can contribute significantly to SAR image interpretation. Therefore, the backscattering mechanism of random rough surface and vegetation composition elements were researched intensively, and related simulation was finished.Secondly, the principle of height measurement of InSAR was analyzed sufficiently, and several different operating modes and their applications were introduced briefly. Meanwhile, some factors which have influence on coherence were discussed. Then, aiming at signal processing of InSAR, principles and some algorithms were analyzed and explored deeply according to the procedure of signal processing.At last, phase unwraping, which is the most important process in InSAR signal processing, was focused. The principle of one-dimension and two-dimensional phase unwrapping were elaborated, and several typical two-dimensional phase unwrapping algorithms were presented and analyzed in detail. Meanwhile, aiming at the disadvantages of typical branch-cuts method, a two-dimensional phase unwrapping algorithm based on improved genetic simulated annealing algorithm was proposed. The proposed algorithm was validated by simulated data and radar data. The experiment result shows that the proposed algorithm has advantages in precision and operation time compared with some typical phase unwrapping algorithm.