Research Of Signal Processing Algorithm For Maneuvering Flying Targets In HF Radar

Radar is an electromagnetic system used to detect and position reflectors, such as aircraft, ships, vehicles and the natural environment, it launches electromagnetic wave to space and receives echo reflected by targets, by comparing the difference between launching wave and its echo to determine whether the target exists, and get target position, velocity or other related information. The HF OTH radar can effectively detect maneuvering target outside of the horizon, and has widely applications. Therefore, the HF-the-horizon radar signal processing problem has attracted researchers'attention.First, this paper studied models of moving targets based on the analysis of motion state of maneuvering target. And then we summarized factors that can broad spectrum of maneuvering targets, so we can provide the necessary maneuvering target model to future simulation analysis.Secondly, this paper had a brief introduction, analysis and comparison of two classical time-frequency analysis methods. Then the signal processing algorithm of maneuvering target based on S-Method has been brought in. Through comparison of these three time-frequency analysis methods, we can see that the signal processing algorithm based on S-Method has a distinct advantage.As HF radar is working in the nature environment with sea clutter, so sea clutter has effects on the signal processing algorithms of HF radar to some extent. This article briefly summarized effects of sea clutter on signal processing algorithms, while brought in four sea clutter suppression filters to reduce the impact of sea clutter. Simultaneously, we designed a notch filter based on envelope fitting. By comparison the performance of those five sea clutter suppression filters, we chose the notch filter based on envelope fitting to improve the performance of signal processing algorithm based on S-Method.Thirdly, this article described two motion compensation algorithm, i.e., high order ambiguity function and adaptive chirplet transform method. By analysis and comparison the simulation results of those two methods, we can see that those two algorithms both can improve the signal to noise ratio of reconstructed target signal, and effectively accumulate energy.Finally, by combining clutter suppression preprocessing algorithm and motion compensation algorithm, the signal processing algorithm based on S-Method can effectively decompose characteristics of multi-maneuvering flying target. It also can extract motion parameters accurately. This thesis also simulated and analyzed the practical situations of conventional targets, maneuvering target, two maneuvering targets and constant turning targets, simulation results verified the validity of the algorithm.