Research On Signal Processing And Simulation Experiment Of MIMO-OTH Radar

Multiple Input Multiple Output over the Horizon(MIMO-OTH)radar is an important research direction of radar systems in recent years due to its excellent performance of both MIMO radar and OTH radar.Based on the construction of a MIMOOTH radar simulation system,this thesis studies the waveform design including spectrum coexistence,the application of the TBD algorithm in the MIMO-OTH radar,and the polynomial-based ionospheric phase pollution correction.The main work is as follows:(1)Based on the ionospheric model and ray propagation model,this thesis establishes a MIMO-OTH radar detection simulation system,and completes the entire signal processing process,including receiving/equivalent emission beamforming,matched filtering,and Doppler processing,Parameter measurement,etc.,and a wealth of simulation experiments have been carried out.The simulation proves that the system can effectively detect the target.(2)In the signal processing of the MIMO-OTH radar,the MIMO-OTH transmitting signal with good characteristics is of great significance for the accurate detection of the target.Aiming at the current situation of many communication services in the high frequency band,this thesis proposes a spectrum coexistence waveform design algorithm.The optimization goal is to minimize the energy in the frequency band occupied by the communication service,and the similarity and constant modulus are used as constraints,and the MM algorithm is used to solve the problem.The simulation proves that the energy distribution of the designed waveform can form a depression in the occupied azimuth and frequency band to avoid mutual interference between the radar and the communication system.(3)Aiming at the problem that the traditional constant false alarm detection algorithm is difficult to detect weak targets.,this thesis applies TBD algorithm to MIMOOTH radar to improve the detection performance of the system to weak targets.In this thesis,the value function under the background of complex Gaussian sea clutter is designed based on the generalized likelihood ratio criterion,and the TBD algorithm is implemented using dynamic programming(DP).In the implementation of the TBD algorithm,the method of eliminating the Doppler parameters is adopted to change the two-dimensional DP into one-dimensional DP,which reduces the complexity of the algorithm and improves the performance of the algorithm.The simulation experiment proves that the detection and tracking performance of the value function designed in this thesis is better than the TBD algorithm with amplitude as the value function;at the same time,it proves the effectiveness of the TBD algorithm in MIMO-OTH radar.(4)Research on multi-mode,multi-path and ionospheric phase pollution of MIMOOTH radar system.In this system,a two-dimensional receiving array is used to obtain the pitch angle information of the target echo,so as to realize the suppression of multi-mode and multi-path.Aiming at the problem of the ionospheric phase pollution of the echo,which leads to the broadening of the sea clutter spectrum,a new polynomial-based ionospheric phase pollution correction algorithm is proposed.The fifth-order polynomial is used to estimate the phase pollution function,and the fifth degree is given.The method of polynomial coefficient estimation.Simulation experiments prove that this algorithm can effectively eliminate the influence of ionospheric phase pollution on echo signals.