Error Analysis And Experimental Verification Of Height Measurement Of Domestic Interferometry SAR Satellite

The Spaceborne Interferometric Synthetic Aperture Radar(InSAR)system uses active microwave sensor to conduct interferometric measurement.It extracts highly sensitive interferometric phase information from the complex image data of the master and slave images to provide the useful information such as surface elevation.Compared to the three-dimensional reconstruction method based on optical remote sensing,InSAR has four advantages.Firstly,SAR has all-weather,all-day observation capability,and the microwave is penetrating,so it can obtain radar images at cloudy and rainy region.Secondly,SAR provides images with both wide swath and wide temporal coverage.Third,image cost is low.Fourth,combining with optical remote sensing,InSAR could obtain a more complete and reliable global basic geographic information.Therefore,InSAR has become research focus as a technical method in remote sensing for all-round,high-precision and high-efficiency access to large scale of basic geographic information.In this paper,we mainly focus on simulation verification and theoretical analysis of height measurement error around the distributed spaceborne InSAR topographic mapping.Firstly,the height measurement error in distributed spaceborne InSAR is theoretically calculated as a function of orbital error,slant range error,baseline error and the phase error.Therefore the error sources are qualitatively assessed and the error propagation pattern are derived.Then,combined with SRTM DEM and the parameters of TanDEM-X,the experimentations are conducted.Each error sources affecting the spatial distribution characteristics are evaluated.Furthermore,each error source that affects the height measurement error is comprehensive analysis from point to surface,and the theory and the experiment corroborate each other from simulation.The main research aspects and innovations are summarized in the following three aspects.(1)Establishing the height error model of distributed spaceborne InSAR.The error sources that affect the accuracy of topographic mapping are comprehensively analyzed,including the orbital error,the slant range error,the baseline error and the interferometic phase error by using the strict and application-oriented spaceborne distributed InSAR geometry.And then the error models of satellite elevation in topographic mapping are constructed.which provides the reference for the engineering development of domestic InSAR satellites.(2)Study on error propagation of height measurement error in distributed spaceborne InSARThe height error model is simulated and analyzed integrating the TanDEM-X parameters.Error sources of height measurement are comprehensive assessed.This provides some reference for the parameter argumentation and engineering development of domestic distributed InSAR satellite.(3)Simulating and verifying the height error model of distributed InSARThe spatial distribution regular of slant range error,baseline error,interferometric phase error on elevation measurement was systematically analysis based on intrinsic interference geometry of spaceborne distributed InSAR.Then the interferometric chain simulation is proposed based on TanDEM-X parameters and SRTM DEM.The interferometic chain simulation and analysis of error model is also achieved by adding various error sources using the SRTM data of the corresponding region and the geometric parameters of TanDEM-X.Simulations validate the error propagation and its spatial distribution of each error source.The images of the interferometric chain simulation strategy are consistent with the real SAR images.Therefore the result is highly reliable and has some certain guiding significance for distributed InSAR satellite engineering.