Error Analysis Of Millimeter-wave Spaceborne Synthetic Aperture Radar Interferometry

The spaceborne Synthetic Aperture Radar Interferometry(In SAR)technology is a new type of microwave remote sensing technology for ground observation.In SAR has important applications in the fields of digital elevation model(DEM)generation,surface movement monitoring and deformation monitoring.With shorter wavelength and higher imaging resolution,the millimeter wave SAR has higher elevation measurement accuracy under the same baseline length.Therefore,millimeter-wave In SAR has become a new research hotspot in recent years.Elevation measurement accuracy is the core indicator to measure the performance of In SAR system.At present,the research on In SAR elevation measurement error is mainly concentrated in the lower frequency bands such as C or X.The millimeter wave In SAR system is more sensitive to errors,so it is necessary to analyze it specifically.This paper systematically studies the sources of error in spaceborne millimeter wave In SAR measurements,and focuses on the analysis of some unique problems of millimeter-wave In SAR systems,such as the effects of orbital three-dimensional errors,reference frequency source errors,quadrature demodulation errors,and registration errors on millimeter-wave In SAR measurement errors.It has certain guiding significance for the design of spaceborne In SAR system.The main work is as follows:First of all,a three-dimensional error model in the geocentric space rectangular coordinate system is constructed,and the influence of the satellite platform parameters in the geocentric space rectangular coordinate system on the altimetry error is researched.Simultaneously overcome the classic baseline error parameters such as length and tilt angle that cannot be directly converted into satellite platform parameters.These studies provide a more direct analysis method for orbit design of millimeter wave In SAR system satellite platform.Secondly,since the millimeter wave In SAR system is more sensitive to the reference frequency source and the quadrature demodulation error of the receiving channel,the received signal model under these two error conditions is established.The imaging results are deduced,and their effects on the interference phase and measurement height are analyzed.The simulation results show that the influence of the reference frequency source error is basically negligible,the influence of the quadrature mediation error has a certain effect.Third,aiming at the difficulty of image registration due to the rapid change of the scattering characteristics of the ground objects in the millimeter wave band,the effect of registration error on the interference phase is analyzed,and the quantitative index is obtained through simulation.Finally,using PS-In SAR technology to analyze the deformation of a Dam in Laos,the experimental results show that unusual subsidence occurred in the final two months before the collapse.The results indicate that,In SAR technology has important practical application value.