Research On Two Dimensional Waveform Design For Airborne Cognitive SAR

Cognitive synthetic aperture radar(SAR)is a new imaging radar system.It can realize the integrated design of SAR receiving and transmitting by using closed-loop feedback structure,through the cognition and application of environmental information,match SAR,targets and environment,and overcome the traditional SAR's weakness,such as ordinary and fixed working mode.Cognitive transmission is one of the essential part of cognitive SAR which is different from traditional SAR.Waveform-design is the basic and key way for cognitive SAR to realize cognitive transmission.Therefore,this thesis focuses on the waveform design of cognitive SAR.(1)This thesis studies the architecture and characteristics of cognitive SAR system,compares and analyzes the similarities and differences between Haykin framework and Guerci framework,defines the components of cognitive SAR system and the key technologies of each part,which provides the basis for the design of cognitive SAR system architecture.(2)The method of clutter information perception based on clutter power spectral density estimation is studied.The problem of clutter information classification and extraction is solved,which lays a foundation for adaptive design of cognitive SAR.(3)The fast time dimension waveform design method based on the joint optimal criterion of signal to noise ratio and resolution constant is studied,and the method of solving the transmitting waveform of cognitive SAR under the joint optimal criterion is derived,which solves the problem of fast time dimension waveform design for imaging requirements.(4)Cognitive SAR's slow-time dimension waveform-design method based on target matching is studied,the analytic expression of slow time dimension signal phase of cognitive SAR Based on target matching is derived.The optimization design of twodimensional waveform of cognitive SAR is realized,and the fast-slow dimension joint anti clutter performance of cognitive SAR is further improved.The effectiveness of the waveform-design methods is verified by the results of experiments It shows that waveform-design methods can solve the needs and problems.