Study On Spaceborne InSAR Absolute Phase Determination And DEM Generation Technology With Its Engineering Application

Synthetic Aperture Radar(SAR),characterized by its all-time and all-weather capability,has been an important means of acquiring surveying and mapping data in complex climate regions.Synthetic Aperture Radar Interferometry(In SAR)is a kind of radar imaging technology developed on the basis of SAR.It can obtain the large-range and high-precision digital elevation model(DEM)in all weather conditions.It is widely researched on topographic mapping,vegetation classification and surface subsidence.DEM is the main product of InSAR technology.With the development of InSAR technology,the amount of data acquired is getting larger,the resolution is getting higher,and the requirements on the efficiency and accuracy of DEM generation are further improved.Absolute phase determination and DEM generation are key steps in obtaining high-precision DEM.In the face of multi-source information(Control Points,Prior DEM,difference frequency data,etc.),absolute phase determination requires different methods of processing.Faced with the different working modes of the In SAR system,the DEM generation model also requires different solving methods.The existence of multi-source information and multi-mode is not conducive to obtaining high-precision DEM in continuously and efficiently.This paper focuses on the self-adaptive determination of the absolute phase of multi-source information and the unified DEM generation model,targets on absolute phase determination and DEM generation in engineering,carries out the following works:1.The classification and application of In SAR system are discussed.Based on the study of the development status of spaceborne In SAR systems both at home and abroad,it has been found that the differences between multi-source information and In SAR system work patterns are not conducive to obtaining high-precision DEM in large batches,continuously,and efficiently.The principle and geometric model of SAR/In SAR imaging are analyzed.The main flow of In SAR acquisition of DEM and the source and characteristics of DEM precision error are studied.2.The theoretical analysis with the existing algorithm of absolute phase determination is carried out.Based on the characteristics of multi-source information,the advantages and limitations of different algorithms are analyzed.The engineering application of the absolute phase adaptive determination of multi-source information is realized,and an optimal processing algorithm can be adaptively selected according to the user providing multi-source data and parameter information.The simulations and measured data are validated by several groups and the processing results are given.3.The target setting and geocoding in the DEM generation link has been analyzed and discussed.In the DEM-generated engineering application,the solving method of the DEM generation model is improved,and the unified processing of the single-base model is realized.4.With the requirements of high-volume and high-precision data processing,absolute phase determination and DEM generation have been designed from input and output interfaces,parameter setting interfaces,high-efficiency operations and intelligent applications.The simulations and measured data are validated by several groups and the processing of the application results are given.