Research On Parameter Estimation Methods Of Maneuvering Targets

In recent years, the detection and tracking of complex moving targets has become a front topic and pressing task in radar signal processing area. Within a short Radar signal processing period, a complex moving target can be first-order approximated to a moving target with constant acceleration, of which the echo model is linear frequency modulation signal. When processing the conventional radar signal, the target’s maneuverability will spread the energy over the Doppler domain, which can decrease the accumulated gain, resolution performance and the output signal-to-noise ratio. What’s more, the detection performance will decrease with the increase of the target’s maneuverability. Therefore, the research on the estimation and extraction method of radial velocity and acceleration parameters of maneuvering targets in signal processing stage has an important impact on the improvement of the detection and tracking performance of maneuvering targets.This dissertation focuses on the exploration of and the research on signal parameter estimation methods of maneuvering targets. The echo signal model of maneuvering target is derived from the echo characteristics of target with constant velocity. In order to further study the maneuvering targets signal processing and compensating methods, an analysis is made on the influence of acceleration information on the performance of traditional spectral analysis.This dissertation introduces three conventional parameter estimation methods of maneuvering targets including dechirping method which uses the idea of ML, Fractional Fourier Transform and Radon-Wigner Transform menthods which both belong to time-frequency analysis. Firstly, the basic principle of three conventional parameter estimation methods of maneuvering targets are introduced. Then, simulations are made to show the influence of different parameters on the performance of each method. Furthermore, the suitable conditions and deficiencies of these methods are briefly introduced. Finally, this dissertation focuses on the analysis of mutual change relation of these methods and the shortcomings of them in handling parameter estimation of multi-component maneuvering targets.Finally, in view of the limitation of the conventional methods mentioned above, a kind of high-resolution parameter estimation method of multi-component maneuvering targets is proposed which combined the ideas of both the latest compressive sensing(CS) theory and the multi-stage approximation method. This method utilizes CS theory and the sparse characteristics of maneuvering target signal to obtain decomposition coefficients projection on over-complete dictionary, then estimates the maneuvering target parameters through1-norm-limited optimization algorithm and multi-stage approximation frequency refining method. A brief description is made of the basic principle and the main idea of compressive sensing system, including the sparse representation, the observation sampling and the reconstruction of signal. The designing process and implementation steps of the method is introduced in detail. Finally, a large number of simulation experiments are made to show the fact that this method can achieve super-resolution ability and ultra-high parameter estimation precision for multi-component maneuvering targets.