Data Acquisition And Processing In Passive Bistatic Radar Target Detection System

With the continuous development of modern radars,since traditional radars transmit electromagnetic energy when they are working.There is a danger of being discovered by the enemy,so the application of traditional radars has been greatly restricted.The theory of passive radar has attracted wide attention from scholars all over the world.Because passive radar listens to existing illuminations and senses tiny disturbances in the electromagnetic filed caused by moving objects in order to detect and track them,and does not transmit electromagnetic energy.So it has low cost,can detect stealth targets,and is not easy to be detected.In addition,the passive radar has problems such as a large amount of single frame data and high false alarm rate,so the research on the data acquisition and transmission in passive radar target detection system becomes very important.In this thesis,we study the data acquisition and processing in passive radar,the specific work content is as follows:1.Data acquisition and transmission in passive radar.In order to carry out data processing operations,reduce the false alarm rate,and obtain the true track of the target,it is necessary to ensure that the data collected by the front-end system is correct.First,the thesis introduces a data transmission method based on the intermediary computer of the passive radar using FM broadcast as transmitter.Then,starting from the knowledge of the band-pass sampling theorem and signal extraction,data loss will occur if the amount of single frame data increases.Based on the three-transmitter single-receiver system,it is calculated that the data volume of a single frame is 75 MB using FM broadcast as transmitter.Then the thesis points out the cause of the data loss problem,and proposes a new method to solve the problem of data loss on passive radar.At last,the thesis proposes an information transmission based on UDP,which is used to transmit the point and the trace using data processing.2.Pre-tracking data processing in passive radar.The thesis divides the data processing in passive bistatic radar into pre-tracking data processing and tracking algorithm.In this system,the radar signal receiver will receive strong clutter signals,which will cause a large number of false measurements to be produced,which will reduce the probability of detection of real targets.Aiming at the problem of too many false alarm points,the thesis proposes and implements a data preprocessing scheme.This scheme uses the centroid method to estimate the target point trace information,and uses the logic method to start the track,and uses NNSF to match the existing measurement information,and uses SPRT to terminate the target flight out of the radar detection range.The thesis uses simulation analysis and actual measurement results to verify the effectiveness of the pre-tracking data processing in passive radar scheme.3.Because the poor angular resolution of the system,it cannot provide accurate angle measurement of the target.The target positioning cannot be completed by relying on the distance-Doppler information of a single station.Therefore,based on multi-station R-D information tracking algorithm is used to obtain the positioning information of the target.Aiming at the problem that a single station cannot complete the positioning,the thesis introduces EKF and UKF based on the "three-transmitter and one-receiver" passive bistatic radar.By comparing the tracking accuracy of the two algorithms,choosing UKF is used as the tracking algorithm in the thesis.Finally,the effectiveness of the data processing scheme described in the thesis is verified by simulation analysis and actual measurement results.