Optimal Waveform Design Of Cognitive Radar In Interference Environment

As the direction of modern radar, cognitive radar has drawn comprehensive attention in the radar academe. Cognitive radar system is composed by three parts:environment perception,repository construction and waveform optimization. Currently, optimal waveform design is the concentration of research. Through adaptive waveform design, radar can effectively suppress the jamming. The dissertation is interested in the optimal waveform design under interference environment. It mainly comprises:The interference environment in which radar works is analyzed. Modeling of clutter and suppressing jamming is constructed. In the thesis we analysis their characteristics and influences to radar performance. Then calculate the SINR of radar in the noise and clutter environment. At last we analysis the anti-jamming performance of fixed waveform by simulation.Aiming at the environment of noise and clutter, the energy spectrum density of the optimal waveform based on the signal-to-interference-plus-noise-ratio criterion under energy constraint is obtained. The optimal waveform by water-falling method is designed. The characteristics of optimal waveform, the influences by the noise, clutter, target and waveform energy to the optimal waveform are expatiated through simulation. By comparing to the fixed waveform, we draw the conclusion that the optimal waveform has benefit to detection.Aiming at the problem that the target impulse response and the interference PSD should been known,SINR loss is analyzed which takes into account the uncertainty of the target impulse response and the interference PSD. Results show that SINR loss fluctuate with the error variance which illustrates the robustness of the waveform design algorithm.Aiming at the problem that the fixed waveform has optimal parameter. We design the optimal parameter of linear frequency waveform and get the useful conclusion which accord with the fact.The optimal parameters of Simple Gaussian Pulse and Gaussian Pulse with Linear Frequency Modulation are designed by the criterion of Fisher Information Distance. The performance of optimal waveform is evaluated.In the end, the main contributions of the dissertation and problems in optimal waveform design to be resolved are concluded.