Research On Ground Wave Trans-horizon Radar Tracking Before Detection Technology

In the process of weak target detection and tracking,the traditional method first performs clutter noise suppression on a single frame of data,and then sets a threshold to obtain a point trace.The threshold setting needs to take into account the false alarm rate.Threshold,there will be missed detection of weak targets.Therefore,in order to optimize the detection and tracking of weak targets,a Track Before Detect(TBD)method has emerged.In the TBD method,the echo data can be accumulated,that is,the data of the single-frame target is not directly processed by the threshold,but the data data is first correlated according to the data relationship between the frames,and then the multi-frame data is processed.Accumulation,detection and tracking processes are based on the accumulation results.For the research of tracking technology before detection,this article will discuss from the following three aspects:First: Discuss the specific application of the dynamic programming method in the tracking technology before detection.As a recursive algorithm,the dynamic programming method stores the solutions of the single-process problems.In the subsequent calculation process,the required data can be directly extracted from the stored information,so there is no need to repeat the calculation,which makes the operation efficiency.Promote.The essence of the dynamic programming method is to find multiple optimal decisions,and then arrive at the final strategy.The cumulative results of each product are evaluated based on a certain scheme to find the optimal way.At the same time,other values rounding.When the accumulation process is completed,the detection result is obtained based on the threshold,and the target trajectory is traced back.Second: Discuss the specific application of TBD technology in the distance Doppler plane.Since the existing TBD method is based on the approximate motion model in the distance Doppler plane,there is a problem of low energy integration efficiency.In this paper,the pseudo-spectrum-based TBD method can effectively combine the target energy and detect the weak target in the distance Doppler domain through the accurate target distance and the Doppler time evolution equation.First of all,according to the condition that the target moves at a constant speed in the Cartesian coordinate system,the distance and Doppler's time-invariant speed square nonlinear function can be used to accurately describe the evolution equations of distance and Doppler about time.This method matches the target speed squared instead of the speed in each direction.Then,according to the obtained time evolution equation,each unit in the distance Doppler plane is predicted to the last frame.At the same time,a pseudo spectrum is constructed around the predicted position according to the point spread function,and multi-frame accumulation is achieved by adding the sample values ??of the pseudo spectrum on several cells to the last frame.Finally,in order to match the speed square of the unknown target,a group of pseudo-Spectrum based Speed Square Filter(hereinafter referred to as PS-SSF)is needed.In this paper,the distance Doppler and speed are theoretically derived The target output envelope of the square domain.The numerical results show that this PS-SSF method can not only achieve effective weak target detection in the range Doppler domain,but also achieve better range and Doppler and target velocity parameter estimation.Third: The application of the tracking before detect method based on pseudo-spectrum in the processing of measured data is discussed.The ground wave trans-horizon radar echo data is preprocessed,and the multi-frame data is processed by the TBD method by constructing a pseudo spectrum.The simulation results show that the pseudo-spectrum method can effectively improve the target detection performance in the weak target environment.