Sparse Array Radar Waveform Design And Orthogonal Angle Estimation Research

Multiple-input multiple-output (MIMO) radar is a kind of new system radars, which is developed in the recent years and has a broad prospect of application. Originally, the array structure of MIMO radar with collected antennas is even, which is complicated and expensive. In order to reduce complexity and achieve higher resolution, the sparse array is used in MIMO radar. With the development of research work, the waveform design, the target detection and the estimations of the parameters have become the main study points of MIMO radar. In this dissertation, MIMO radar with collected antennas of uneven and sparse array is the research object, and its waveform design and angle estimation are studied. The main research contents of the dissertation are as follows.The signal model of MIMO radar of even array is analysed, statistical MIMO radar with transmitting and receiving diversity, statistical MIMO radar with transmitting diversity only, statistical MIMO radar with receiving diversity only and MIMO radar with collected antennas are discussed separately. On the basis of the key techniques of the directional diagram of sparse array and virtual elements, the signal model of MIMO radar of sparse array is given.The design of phase-coded and orthogonal multiple-frequency signal of MIMO radar is studied. The genetic algorithm is used for orthogonal optimal design of polyphase coded and OFDM polyphase coded signal. The specific optimization rule is proposed. Besides, By means of analysising the ambiguity function and cross ambiguity function of OFD-LFM signal, the relationship of its parameters and cross-correlation output is obtained.On the basis of the signal model of MIMO radar of sparse array, the joint direction of departures (DODs) and direction of arrivals (DOAs) estimation using Capon algorithm and MUSIC algorithm is discussed, and the result is compared to the angle estimation of MIMO radar of even array. The final result shows that the two kinds of algorithm can locate both single target and multiple targets. Compared to Capon algorithm, MUSIC algorithm has better resolution capability of near targets, but longer computing time. Compared to the condition of even array, resolution capability of near targets is better while the spatial spectrum of the condition of uneven array is less falter when the same algorithm is used.