Multi-channel InSAR Interferograms Simulation Method Considering Layover and Shadow

  Objectives  In order to simulate the phenomenon of layover and shadow in synthetic aperture radar (SAR) images better in the simulated interferogram, and to provide a suitable data source for the design of multi-channel interferometric synthetic aperture radar (InSAR) system and the research of related algorithms, a simulation method of multi-channel InSAR interferogram considering layover and shadow is proposed.

  Methods  Firstly, according to the basic principle of InSAR, the real interferometric phase of each pixel for each interferometric channel is calculated using the DEM and the designed multi-channel InSAR system parameters. Secondly, the corresponding phase noise is generated and added to the real interferometric phase according to the probability density function of the interferometric phase noise. Thirdly, the layover areas and shadow areas are detected according to the exact geometric relationship between the multi-channel InSAR system and the DEM. Fourthly, the initial interferometric phases of the layover areas overlapped in the same resolution unit are weighted superimposed, the initial interferometric phases of the shadow areas obtained in the third step is replaced by Gaussian white noise, and the initial interferometric phases of the other areas are not processed. Therefore, the simulated multi-channel InSAR interferograms that takes into account layover and shadow are obtained.

  Results  Three simulation experiments are carried out with three different groups of DEM. From the simulated interferograms using the proposed method in the three experiments, it can be seen that the interferometric phase in the layover areas is noise or even ambiguous with reverse fringe frequency, and the interferometric phase in the shadow areas is random noise, which are very consistent with the characteristics of the real interferograms. However, the characteristics of the layover area and shadow area cannot be seen in the interferograms simulated by the original method without considering layover and shadow. Thus the effectiveness of the proposed multi-channel InSAR interferograms simulation method is verified.

  Conclusions  The simulation results and related analysis show that the multi-channel InSAR interferograms simulation method is simple and fast, and takes into account the influence of layover and shadow on the interferometric phase, so it can provide more realistic simulation data for the research of multi-channel InSAR techniques and related algorithms.