| Traditional radar focuses signal processing on the receiver, and don't make full use of transmitter. The closed-loop system of cognitive radar, to be the next generation intelligent radar, can utilize the transmitter to improve the performance of radar. The cognitive radar is composed by two parts: Knowledge Aided and Adaptive Waveform Design.The dissertation is interested in the waveform design of cognitive radar and studies the algorithms of waveform design under different prior information and criterion. It mainly comprises:1. Aiming at the problem that the weak targets can easily be covered by strong clutters, a way to suppress clutter by waveform design under the criterion of minimum interference of clutter is proposed, and then the maximum SCR at the distance cell of target is got.2. Aiming at the problem that the SNR at the output of matched filter is related to waveform transmitted, a concept of matched transmitter and the methods of waveform design are proposed and then the improved SNR is attained.3. Aiming the problem that the bandwidth of waveform designed may be too wide or too narrow, an algorithm of waveform design under the restraint of bandwidth is proposed. It can improve the SCNR at the output of matched filter while satisfy the requirements of bandwidth.4. Aiming the problem that the waveform designed under the criterion of maximum mutual information is complex when clutter exist, a suboptimal method is used to get the waveform, and comparing with the LFM, it can attain more information about targets.5. The influence of different prior information is analyzed. The different waveforms are designed with different prior information, such as different targets, different noise, different clutter. The factors that affect the waveform is analyzed.The effectiveness of the methods are validated by simulations. The results show that different purposes are attained by waveform design under different criterion. Comparing to the traditional radar, cognitive radar has advantages. |
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