Research On Enhancing Regional Targets Dectection Of Bistatic MIMO Radar

As a new radar system,bistatic MIMO radar combines the advantages of bistatic radar and MIMO radar,and has attracted the attention of domestic and foreign scholars since its introduction.Aiming at the problem of transmit power divergence caused by the transmission of orthogonal signals from traditional MIMO radar,this paper studies the technology of bistatic MIMO radar for enhancing the capability to detect regional target.The main work is summarized as follows:1.Bistatic MIMO radar for waveform design based on transmit beampattern design is studied.First,in order to focus the power and improve the output signal-to-noise ratio(SNR),a method of maximizing the signal-to-interference-to-noise ratio(SINR)is proposed.The proposed covariance matrix takes into account the waveform constant modulus characteristics,also can effectively improve the SINR.The simulation results show that the designed covariance matrix can not only focus the transmit power but also have higher SINR.Secondly,in order to overcome the shortcomings of low emission efficiency due to the uneven transmission power of different array elements,a MIMO radar waveform design method is proposed to control the variation of the beam weight of the basic beam.The set of emission waveforms satisfying the constant mode characteristic is constructed.Then the problem of power uniformity is transformed into the weight vector optimization problem,and it is solved based on the sequence cone programming(SCOP)method.The proposed method can flexibly equalize the peak beam side lobe level and the element transmit power uniformity according to the practical application requirements.The simulation results show that the proposed method can take into account the performance of the element power uniformity and peak side lobe level.2.Bistatic MIMO radar waveform design based on maximizing the output SINR is studied.In order to improve the SNR and enhance the detection performance of radar targets in presence of signal-dependent interference,two methods of bistatic MIMO radar emission waveforms and receiver joint optimization are proposed.Firstly,the model of joint waveforms and receivers in presence of signal-dependent interference is established.The model is transformed by convex relaxation,and then the model is obtained by using the dichotomy method to obtain the constant modulus emission waveform.In order to reduce the computational complexity of the algorithm,a cyclic optimization algorithm based on Charnes-Cooper transform is proposed,and the constant modulus transmission waveform is obtained by using the rank-one approximation method combined with the nearest neighbor algorithm.The proposed method reduces the complexity of solving the algorithm in the process of single cycle optimization,and effectively reduces the computational complexity.The simulation results show that the proposed method can accelerate the optimization while ensuring the convergence,and the optimized waveform has the constant mode characteristic.3.Bistatic MIMO radar detection enhancement methods based on emission weighting matrix design are studied.In order to avoid the influence between the power focusing effect of the transmitted waveform and the matching performance at the receiver,a beam-weighted network model is established.Then the Bistatic MIMO radar transmission waveform design can be transformed into the design problem of base beam and its emission weighting matrix.Two emission weighting matrix design algorithms are proposed.Firstly,a method of emission weighting matrix design is proposed based on the beampattern matching criterion for the problem of transmission power transmission of traditional MIMO radar.The proposed method can reduce the hardware requirement and improve the radar target detection performance.The simulation results show that the proposed method can match the expected beampattern and have lower side lobe level.Secondly,in order to improve the detection performance of bistatic MIMO radar in presence of signal-dependent interference,an algorithm for weighting matrix design is proposed to maximize the SINR.The proposed algorithm can control the degree of freedom flexibly according to the number of disturbances,signal energy and so on.It has better interference suppression effect,which is helpful to enhance the target detection performance of bistatic MIMO radar under interference conditions.The simulation results show that this method can effectively improve the SINR under the premise of ensuring the constant modulus characteristic of the transmitted waveform.