Research On Interferometric Parameters Joint Calibration Of Airborne Double-antenna InSAR System

In order to improve the accuracy of DEM acquired by InSAR, every flight requires laying corner reflectors to calibrate the interferometric patameters. However, laying corner reflectors not only increases the field surveying and mapping work, but also wastes a lot of human and material resources. Therefore, this paper engaged in an exhaustive study of the topography3D reconstruction model of airborne InSAR, interferometric sensitivity equation model and selecting the height connection points. Then a new joint calibration method of airborne dual-antenna InSAR was proposed to calibrate all the interferometric system parameters of flights at the same time and reduce the workload.The main work is as follows:(1)3D Reconstruction Model. Starting from the basic equations of InSAR and making full use of the basic measurement values, this paper got the topography reconstruction algorithm of the orthogonal and squint model relied on ellipsoid earth and spherical plane wave.(2) Selecting Height Connection Points. This paper proposed a new selecting height connection points method based on feature extraction, which combined feature selection operators, maximum coherent registration and PS target point selection to select connection points with obvious scattering characteristics and stable amplitude and phase. And the experiment results demonstrated that the algorithm simplified subsequent operation in selecting height connection points and improved the stability and accuracy of height connection points.(3) Interferometric Sensitivity Model. This paper first got the sensitivity equations based on the target location equations and determined the key parameters of InSAR suitable for airborne SAR system, then demonstrated the key parameters of airborne SAR system and principles of locating reflectors by experiments.(4) Joint Interferometric Calibration Model. According to the accuracy difference of calibration points and height connection points, this paper established different adjustment equations and proposed the joint interferometric calibration model to calibrate all the interferometric system parameters of flights. And the experiment results showed that new model was reasonable and pratical.