The Design Of Transmit Beamforming And The Research Of DOA Estimation For MIMO Radar

The concept of MIMO radar is proposed due to the inspiration of the matureMIMO technology in communication sector. The MIMO radar uses antenna arrays bothin the transmitter and receiver, and the waveforms of the transmiters are different. Dueto the applications of waveform diversity techniques, MIMO radar providesimprovment to the performance in direction of arrival (DOA) estimation and targetdetection. The waveform design is one of the most significant areas of MIMO radarresearch.This thesis concentrates on the design of transmit beamforming for MIMO radar.Firstly, this thesis discusses two existing methods of transmit beamforming for MIMOradar system, which have been widely used: transmit beamforming for MIMO radarsystems using signal cross-correlation and transmit beamforming based on semi-definiteprogramming. These methods own ideal performance on transmit beam-patternmatching. However, for the two methods, the transmit waveform of each transmit unit ishardly obtained directly and the computation is complex. To solve these problems, thisthesis focuses on beamspace-besed transmit beamforming. This algorithm uses theproperty of Rayleigh entropy to achieve the analytical solution avoiding the uses ofiterative algorithms. The waveform of each transmit unit is easily obtained and thecomputation is efficient, although the beam-pattern is not matched as well as the priorones. On the basis of this algorithm, the MUSIC DOA and the ML DOA estimation arediscussed. Comparing with the traditional MIMO radar which transmits orthogonalwaveforms, the simulation shows that the SNR of the receivers is highly increased andthe target resolution is significantly improved.