Radar Signal Characteristic Control Oriented Waveform Design And Waveform Reconstruction Method

Waveform design and waveform reconstruction are two important research aspects in radar field. To simultaneously meet various indexes required by the waveform design or waveform reconstruction is a complicated joint multi-objective optimization problem, which however cannot be addressed directly in an efficient way.Keeping some typical dynamic systems in chaotic state can make it generate chaotic signal, which shows good correlation properties and ideal ambiguity function. Because of its natural characteristics, chaotic signal is widely used in radar waveform design. However, when applied to radar systems, the signal generated by typical chaotic systems is difficult to fully meet the characteristics of signal sparsity, controllable frequency spectrum and low peak to average power ratio. Hence, we propose an application characteristic oriented signal designing scheme. In this paper, we treat radar waveform as part of the solutions of dynamic network and propose a dynamic system to solve the waveform design and waveform reconstruction based on the extraction and feedback of signal characteristic. We exploit the chaos and sparsity of the signal to reduce the searching range and decouple parameters in the multi-objective optimization problem.Due to the structure and parameters of the system we proposed in this paper are known, we can reconstruct the signal directly. When partial information of system is unknown, synchronization controller or sparse recovery algorithm can be employed to reconstruct the signal.Main works and innovations of this thesis are as follows:1. We construct sparse dictionaries based on signal characteristics. The base waveform is optimized by the method of frequency domain optimal waveform design. The sparse dictionary is extended and designed by a set of the base waveform.2. The thesis design and analyze a dynamic system, which is a closed loop structure constructed by sparse dictionary, sparse coefficient controller, measurement matrix and signal synthesis. We analyze the system's dynamic behavior and the performance of the output chaotic signal, which possesses good application characteristic.3. On the basis of the signal generation system proposed in this paper, the multi-channel coupling waveform generation system are proposed here. The output signals of the multi-coupling system can be used as transmitted waveforms of MIMO radar systems.4. Since the system structure and parameters are known, we can get the reconstructed waveform directly by the correlation between compressed signal and sparse coefficients. When the partial information of the system is unknown, we reconstruct the signal by using synchronization controller or by the sparse recovery algorithm. We applied the signal reconstruction scheme to the receivers of the multi-channel coupling waveform generation system, then the signal reconstruction of multi-system is achieved.The experimental results of this paper show that the signal generated by the system we proposed possesses the characteristics of chaos, sparsity, controllable spectrum, low peak to average power ratio and convenience for reconstruction, etc. So the dynamic system can be used as a new type of radar signal source.