Waveform Design And Simulation Of Cognitive Radar For Extended Target Detection

With the rapid development of modern military technology, modernwarfare radar requirements are also increasing. It requires radar further detectionrange, higher tracking precision, more accurate target recognition, strongeranti-interference ability and more agile response. At the same time, not only thesurvival of radar, concealment, anti-interception, anti-jamming and anti-stealthability is facing more and more serious challenges, but also need to have adiverse work mode radar, multi-task and handle diverse goals. This promotes thebirth of cognitive radar, which can adaptively adjust the transmitted waveformfrom the prior knowledge of information and the receiver‘s feedback. Andcognitive radar has been widely studied by many scholars in recent years.To improve cognitive radar detection performance of the time domainwaveform, this thesis’s research object is the extended target detection. Inaddition, in order to make the waveform can be applied to the actual radarsystem and the work scene, especially to make full of cognitive radarintelligence transmitter power, wide bandwidth and constant amplitudeconstraints should be considered in the process of waveform design. Firstly, this paper introduces the basic structure of cognitive radar, on this basis, themathematical model of point target and extended target echo, the method ofwaveform design optimization and the relationship between the target detectionand transmitted waveform have been studied; Secondly, this article alsoillustrates the application of the rule of fuzzy function, signal to noise ratio andinformation theory in radar waveform design; Finally, the signal to noise ratiocriterion is applied to transmitted waveform optimization design of cognitiveradar, focused on the issue that the signal-to-clutter-and-noise ratio (SCNR) ofecho signal, aimed at the issue that the signal-to-clutter-and-noise ratio (SCNR)of echo signal is low when cognitive radar detects extend target. The relationbetween the SCNR of cognitive radar echo signal and the energy spectraldensity (ESD) of transmitting, is gotten by establishing extended targetdetection model other than previous point target model; According to themaximum SCNR criterion,the global optimal solution of the transmitting signalESD is deduced; In order to get a meaningful time-domain signal, ESD issynthesized to be a constant amplitude based on phase-modulated aftercombining with the minimum mean square error and iterative algorithm, whichmeets the emission requirements of radar.. In the simulation, the amplitude oftime-domain synthesized signal is unity, and its SCNR at the output of thematched filter is19.133dB, less than0.005dB compared with the ideal value.The results show that not only can the time-domain waveform meet therequirement of constant amplitude, but the SCNR obtained at receiver output can achieve the best approximation to the ideal value, and improve theperformance of the extended target detection.