Research On Extended Target Detection And Parameter Estimation

Radar target signal detection and estimation are key parts of radar signal processing. The traditional methods of target signal detection and estimation are mainly based on the low range resolution radar, which treat a target as a point-target. In order to improve the ability of detection and the accuracy of measurement, the bandwidth technology has been adopted widely in modern radar technology recently, especially in precision guidance radar. Through this way, the resolution is substantially increased and the width of the range resolution unit can be much less than the size of the target. In this case, the number that the target occupies continuously in the radial range is more than one. So the target is called range extended target. The traditional point-target detection and parameter estimation methods are no longer suitable for broadband radar. For these reasons, the range extended target detection and parameter estimation in high range resolution radar have become a research focus.In this dissertation, some classical theories of signal detection and parameter estimation are introduced in detail, several classical methods of signal detection and parameter estimation in low and high range resolution radars are both analyzed and summarized. Several methods'performances are analyzed and verified by experimental simulation separately too.On this basis, this paper has carried up the research work; mainly included two parts as follows:(1) A novel extended target approach based on maximum and minimum radial length restriction and band-limited parameters model is raised. The range extended target's echo is expressed as the sum of several frequencies in band-limited range. The target detection is converted to GLRT(generalized likelihood ratio test) with several unknown parameters(different frequency components's amplitudes and angles) and parameters limited. According to this method, a new detector is constructed.(2) Another novel method of range extended target detection is presented based on band-limited super resolution parameter model. According to the position and the radial length of the detected target, it moves the start position of the target to zero frequency by frequency moving method, and estimates each frequency component's amplitude of band-limited signal based on the super resolution power spectrum in least squares technique.