Research On Rotating Target Detection And Parameter Estimation In SAR

Since SAR can work at all-time, all-weather and have high-resolution, it has been widely used in both military and civil applications. SAR imaging has replaced the position of optical imaging in many situations. SAR Ground Moving Target Indication(GMTI), as an important application of SAR, plays a key role in military, especially in the detection of the battlefield environment. There are many flaws in the detection of rotation target in the traditional SAR-GMTI. The rotation of targets often contains beneficial information for SAR image interpretation, such as automotive radar rotation, helicopter rotor rotation, etc. The rotation information can help us to identify the type of targets. This paper studies on rotating target in SAR GMTI and parameter estimation.This paper mainly contains:(1) The SAR echo model of rotation target is established in both single-channel system and dual-channel system. Based on the sinusoidal modulation on the echo and Paired Echo Principle(PEP), we study the typical characteristics of rotation target with different rotation parameters in SAR image, which is helpful for us to interpret the information in SAR images.(2) For the single-channel SAR system, it is hard to detect the rotation target with low speed. A method based on Chirplet decomposition is proposed to detect the rotation target. By the characteristics of rotation target in the time-frequency domain, the rotation target can be separated from the stationary target. Using the separated signal characteristics of rotation, we put forward a useable method to estimate the parameters of the rotation target.(3) For the dual-channel SAR system, a rotation detection method based on Displaced Phase Center Antenna(DPCA) is put forward, which can detect the rotation target quickly in high SNR. According to the analysis of sinusoidal modulation characteristics of echo azimuth amplitude signal after pulse compression, we obtain the converting relationship between the amplitude signal and target rotation parameters. Finally, rotation parameters are estimated.In this paper, we study on the methods of rotation target detection and rotation parameters estimation, both in single-channel system and dual-channel system. The detection performance and estimation accuracy of the methods are analyzed and discussed by simulations. The research work in this paper has a certain theoretical and reference value.