Waveform Optimization For MIMO Radar In The Presence Of Clutter

As a new radar system, multiple-input multiple-output(MIMO) radar has got widespreadconcerns from professionals and academic researchers. Generally, conventional phased arrayradar transmits coherent signals.While each antenna element in MIMO radar can transmitarbitrary signals. The method of transmission signals with waveform diversity gives MIMOradar better system performances in mitigating signal fading, enhancing the resolution andimmunity than phased array radar. So, the performances of parameter estimation, targettracking and recognition, and target detection can be significantly improved.The thesis focuses on MIMO radar waveform optimization. The work of this paper canbe summarized as follows.(1)The signal model of MIMO radar is briefly described in this paper. The unique signalprocessing is elaborated. Because MIMO radar transmit mutually orthogonal signals duringits operation, three common orthogonal signals are introduced.(2)A method based on Cramer-Rao bound (CRB) for MIMO radar waveformoptimization to improve system parameter estimation accuracy in the presence of clutter isproposed in the paper. Through Trace-opt constrain criteria, Det-opt constrain criteria,Angle-only constrain criteria, Amplitude-only constrain criteria and Schur’s complementrelated theory, the optimization problem can be converted to a semi-definite programming(SDP) optimization problem to be solved. Simulations verify the validity of waveformoptimization model.(3)A robust waveform optimization is proposed to solve the problem that the errors ofthe dependent parameters for waveform optimization degrades the system robustness. Thepaper puts forward a robust method for MIMO radar waveform optimization under the worstparameter estimation performance. Firstly, the waveform optimization model is introduced inthe presence of clutter. Assuming that the rang of parameter estimation errors is known, theexpression of the robust waveform is deduced. Because the optimization problem is a highlycomplex nonlinear function with respect to optimization variables, it is hardly to sovle.Tosovle the problem, the diagonal loading method is applied to convert the problem to a SDPproblem, which can be efficiently solved. Comparing with uncorrelated signals, simulationsshow that the waveform obtained by the proposed method has good robustness on theparameter estimation errors.