Study On The Key Techniques Of Signal Processing In PD Radar

PD radar is a kind of advanced pulse radar which using coherent processing. It provides an active field for development of the signal processing techniques. This dissertation is based on the subject" Research on constant false alarm rate (CFAR) detection for one certain type of airborne PD radar " and " Research on ambiguity resolution in range and velocity for one certain type of shipborne radar". In this dissertation several key problems about signal processing for PD radar have been studied. The main content includes: Clutter tracking technique, CFAR detector based on clutter tracking and ambiguity resolution in range and velocity etc.In chapter one, the origin and development of PD radar technique are reviewed. The automatic radar detection and CFAR processing methods, ambiguity resolution for PD radar are summarized. The research contents and objectives of the dissertation are given.In chapter two, airborne PD radar clutter models are discussed. A kind of airborne PD radar clutter emulation algorithm is introduced and improved. The expression enables the accurate and efficient simulation of radar sidelobe, main lobe, altitude-line clutter and coastline clutter. Comparing emulated and real data, we proved the validity of this emulation to airborne PD radar clutter.In chapter three, we discuss non-linear filter designing used for pre-processing clutter in clutter tracking channel. We apply K-nearest neighborhood (K-nn) algorithm to pre-process clutter and propose a modified scheme based on pyramidal morphology algorithm. The modified algorithm does better than the original algorithm on the Peak Signal-to-noise Ratio (PSNR) of clutter gray image and follows the requirement on pre-processing clutter in clutter tracking channel.In Chapter four, the clutter tracking technique based on image processing is proposed. We apply Fuzzy C-means Clustering (FCM) algorithm to the clutter tracking. According to the clutter dependence in the time and space, we propose a method of defining the initial fuzzy membership function. This method is verified to be successful in reducing the computation burden using simulated data. We apply Local Entropy algorithm to the clutter tracking. The hybrid filter, which is composed of K-nn filter and local entropy filter, has been used to detect clutter edge. We propose the judging criteria of similarity to Maximum Local Entropy that is used to segment the simulated clutter data after local entropy filter. The FCM algorithm and Local Entropy algorithm have difference in the form of output, efficiency and suitable CFAR detectors. Those algorithms have been verified to be successful in several typical simulations.In Chapter five, we introduce the research on CFAR detection based on the clutter tracking. Regarding the result of clutter tracking as the background information we propose clutter feature (CF) -CFAR detector and structuring element (SE)-CFAR detector. They are based on different results of clutter tracking. They have different reference cell structure and are suitable for one or two-dimensional detection respectively. Their detection performance in clutter edge region are analyzed and simulated by the MonteCarlo method. They have very good behaviors compared with CA, GO-CFAR detectors at clutter edges.In Chapter six, the research on ambiguity resolution in range and velocity in PD radar is discussed. First we study and improve cluster algorithm, put forward a sliding window correlator algorithm. This algorithm's performance is analyzed and emulated. Then we introduce the design and realization of this algorithm in one certain type of ship-borne radar by parallel DSP. In the last part, we introduce real-valued genetic algorithm applied to ambiguity resolution. Based on the ambiguity resolution principle, we design the fitness function. A good result in the probability of ambiguity resolution using real-valued genetic algorithm is get.In chapter seven, the research results are concluded. The further developments and the questions needing continuing studying are p...