Research On Multi-baseline Phase Unwrapping Technique And Elevation Inversion Accuracy

Multi-channel(multi-baseline/multi-frequency)interferometric synthetic aperture radar(InSAR)measurement technology is a new type of synthetic aperture radar surface survey technology,which is extended from the theory of single-baseline InSAR technology.Combined with the principle of synthetic aperture imaging and interferometry,high-precision 3D spatial information of ground objects is obtained through the phase information of echo signals,which improves the accuracy of InSAR mapping of complex terrain.The surface space high-resolution image with large detection range,high precision and high reliability can be obtained in all-weather and all-weather conditions.It is the latest technology to use remote sensing technology to obtain target three-dimensional information and small deformation information.This paper mainly studies the multi-baseline phase unwrapping technique and the accuracy of elevation inversion.The main contributions of this thesis are as follows:(1)A two-stage programming multi-baseline InSAR phase unwrapping method based on Unscented Kalman Filter(UKF)and Particle Filter(PF)for rugged mountain terrain is proposed.In this method,the phase gradient information of each interferogram is obtained by using the Chinese remainder theorem(CRT),and then the multi-baseline phase unwrapping is carried out by combining unscented Kalman filter and particle filter according to the gradient information.(2)The accuracy of multi-baseline InSAR height inversion is analyzed.By using the data of multiple interferometric phases observed from earth and referring to the height measurement formula of single baseline InSAR,the mathematical relationship between multi-baseline height accuracy and system parameters is established,and the variation law between them(especially the number of base lines and baseline length)is analyzed,and three kinds of weighting coefficients are proposed to improve the accuracy of height inversion.The accuracy of height inversion after multi-baseline phase unwrapping is analyzed by using two-stage programming method(TSPA)method.As mentioned above,some achievements have been made in the study of multi-baseline phase unwrapping technology and elevation inversion accuracy.In the aspect of multi-baseline phase unwrapping,a two-stage programming multi-baseline InSAR phase unwrapping method combining unscented Kalman filter and particle filter for rugged mountain terrain is proposed.This method combines two filtering methods on the basis of TSPA to improve the accuracy of multi-baseline phase unwrapping and can be applied to InSAR data generated by many kinds of terrain.In terms of the accuracy of height inversion,the advantage of the accuracy of multi-baseline height inversion is analyzed,and three kinds of weighting coefficients are proposed to improve the accuracy of multi-baseline height inversion.It provides a certain reference for the future research on the accuracy of multi-baseline height inversion.