Interferometric Sar Altimeter Velocimetry

Interferometric synthetic aperture radar (InSAR) is function expansion of synthetic aperture radar (SAR). It includes two work modes: cross track interferometry SAR (CT-InSAR) and along track interferometry SAR (AT-InSAR). CT-InSAR can get the goal ground's elevation, and AT-InSAR can realize ground slow moving target detection. Because of its high precision measurement and may work in all weather and all day, InSAR has great value in military and civil, so it has become one of the focuses of research in the SAR field. This dissertation mainly studies several crucial issues in InSAR technologies, such as image coregistration in CT-InSAR, moving target detection and estimation of motion parameters in AT-InSAR. Finally, Phase separation in InSAR with hybrid baseline is studied.The major work of this dissertation is as follows:1,Basic principles of SAR elevation measurement and ground moving target detection are detailed. First, mathematical model of CT-InSAR is introduced. The dissertation points out that under certain approximative conditions, a linear relationship exists between the interferometric phase and the elevation. Then the dissertation analyzes the model of moving targets'echoes in AT-InSAR, classificates and briefly introduces the detection methods that have been proposed.2,An estimation method for CT-InSAR interferometric phase with adaptive image coregistration is studied. The characteristic of this method is that image coregistration and interferometric phase estimation are done at the same time. The dissertation gives the method's mathematical model and processing steps, then improves it. Finally, the effectiveness of the improved method is verified with the real data from SIR-C/X–SAR.3,A moving target detection method base on the covariance matrix is studied. The dissertation firstly introduces the methods that have been proposed, such as small values, magnitude difference of non-diagonal elements, then a method based on the covariance matrix eigenvalue ratio is proposed. The dissertation compares these methods with traditional ones, and points out that such method has effective clutter suppression, while computation is larger. 4,An estimation method for moving targets'velocities based on the combination of DPCA and DCFT is studied. The moving targets'Doppler parameters can be estimated with DCFT which is based on energy entropy. Then according to the relationship between these parameters and moving target's velocities, the range velocity and azimuth velocity can be estimated.5,Phase separation in InSAR with hybrid baseline is studied. In order to obtain elevation and velocities at the same time, we can tilt the baseline, then measure elevation and velocities by separating the hybrid phase. The dissertation derives the theoretical model and verifies the feasibility of this method through a simulation on the computer, then points out that in such case, moving targets can be detected firstly by methods based on the covariance matrix, then the phase can separated.