The estimation of the range of the center of the radar beam,that is the range between the center of the target area and the radar platform,is determined by the method of sum-difference amplitude-comparison.The range gate corresponding to the null depth is the estimated distance.In the actual situation,it is difficult to determine the position of null depth due to the influence of noise,so the range estimation accuracy is poor.In order to obtain a high-precision range,a radar ranging method based on total variation minimization is proposed,which can effectively perform distance estimation.The method of minimizing the total variation can suppress the noise level well,improve the signal-to-noise ratio,and make the processed data flat,so it is easy to determine the position of null depth of sum-difference amplitude-comparison,thereby further determining the range gate corresponding to zero depth.Simulation results show that the method can well suppress noise and effectively improve the ranging accuracy.

The model of direction finding error and ranging error were established based on the principle and method of two-dimensional passive location. The analysis of error model show that, phase difference change rate error was the main influence factor of location error. In addition, not only the influence of relative position of target and observation station on azimuth error, but also the influence of direction finding error and phase difference rate error on distance measurement were analyzed. Finally, the relative ranging error of the ranging data was realized by using extended Kalman filter (EKF), which effectively improves the passive positioning accuracy of the moving observation station to the fixed target.