Error Analysis Of Elevation Measurement Based On InSAR Imaging Radar Altimeter

In recent years,with the rapid development of Interferometric Synthetic Aperture Radar(InSAR)technology,the US JPL proposed that KaRIA adopted by the SWOT system introduces the radar altimeter into the InSAR imaging altimeter stage.Compared to the traditional star height gauge,the INSAR imaging radar height gauge can obtain seas and two-dimensional spatial information,while the relative elevation measurement accuracy can reach millimeter,which is of great significance for marine kinetic research.The relative elevation measurement accuracy is one of the important indicators of the InSAR imaging radar altimeter system.This thesis is based on the principle of InSAR elevation measurement,through simulation experiments to analyze the influence of system parameters on relative elevation accuracy.This work is of great significance to guide the subsequent design of the InSAR altimeter system.The main research work is as follows:?(1)In-depth analysis of system parameters on the measurement error of the InSAR imaging altimeter.The various system parameters of the InSAR imaging altimeter have different effects on the relative elevation accuracy.At present,only the baseline and interference phase are studied at home and abroad,and there is no systematic study and comparison of each parameter.In response to this problem,this paper analyzes the main system parameters that affect the relative elevation accuracy;provides the transfer coefficient between the error of each system parameter and the relative elevation accuracy of the sea level;uses the single control variable method to obtain the error pair of each system parameter sensitivity to relative elevation accuracy;compare the theoretical results with simulation results by substituting parameter values into the derivation formula for theoretical analysis;and verify the theoretical analysis with the actual data of Tiangong,thereby verifying the error analysis based on simulation effectiveness.The results show that the interference phase error is the main factor affecting the relative elevation accuracy.(2)In-depth analysis of the effects of baseline jitter on the relative elevation measurement accuracy of the InSAR imaging altimeter.The baseline is an important parameter in the InSAR imaging radar altimeter system and the baseline jitter has a great impact on the InSAR elevation measurement.In this regard,this paper first analyzes the influence of the baseline jitter on the relative elevation measurement accuracy,a baseline jitter error analysis model is proposed.Based on the InSAR imaging radar altimeter baseline jitter model,theoretically derived the relationship between baseline jitter and relative elevation accuracy and the simulation experiment is carried out for different baseline jitter conditions,and the correctness of theoretical model is verified.The study shows that the jitter frequency affects the relative elevation change,and the jitter amplitude affects the relative elements.