Research On Waveform Design Technology For Airborne MIMO Radar

Airborne multiple-input multiple-output(MIMO)radar often works in the presence of strong ground clutter.A technique,called space-time adaptive processing(STAP)can effectively suppress clutter.However,more and more complex external interference environment seriously affects the performance of STAP to suppress clutter.But the detection performance of airborne MIMO radar can be further improved by designing the transmit waveform of airborne radar.In this thesis,the waveform design technology of airborne MIMO radar for detecting ground moving target is studied.The main work is as follows:The first part introduces the basic knowledge of MIMO radar waveform design,establishes the target and clutter signal model of airborne MIMO radar and describes the principle of waveform design.In the second part,the waveform design problem with constant modulus and similarity constraints are studied,and a fast waveform design optimization algorithm is proposed.The simulation results show that the proposed algorithm is faster than the existing algorithm,which can significantly improve the signal to interference plus noise ratio(SINR)and effectively suppress clutter.The waveform designed has the characteristics of constant modulus and similarity.In the third part,the problem of waveform design for spectral coexistence in spectrally crowded environment is studied.The peak-to-average ratio(PAR)and similarity constraints are enforced on the waveform,and an iterative optimization algorithm based on convex optimization is proposed.The simulation results show that the proposed algorithm is faster than the existing algorithm,which can significantly improve the SINR and achieve spectral coexistence.The waveform designed satisfies the PAR and similarity constraints.In the fourth part,the robust waveform design problem is studied when the priori information of the target is unknown.Firstly,a method of waveform design based on the statistical characteristics of target priori information is proposed,and a fast iterative optimization algorithm is proposed to solve the waveform design problem with constant modulus and similarity constraints.Then a joint robust design method of transmit waveform and receive filter bank is proposed.Taking the worst-case SINR as the design criterion,the PAR and similarity constraints are enforced on the waveform,and an iterative optimization algorithm based on convex optimization is proposed.The simulation results show that the proposed waveform design methods are robust and can effectively improve SINR.