Research On PRI Sorting Method For Radar Signals In Complex Environments

Radar signal sorting is one of the key technologies in electronic reconnaissance systems,whose main purpose is to separate the overlapping pulses of different radar emitters received by the receiver.Radar signal sorting is a prerequisite for subsequent identification and analysis of radar pulses to obtain information such as the type,location,and threat level of the target radar,and is an important guarantee for the success of modern electronic warfare.There are radar signal sorting methods such as Cumulative Difference Histogram(CDIF).In a complex electromagnetic environment with a large number of radiation sources,high pulse loss rates,and interference pulses,there are problems such as low sorting accuracy,easy sorting and batch addition,and long sorting time for complex modulation forms of radar signals such as jitter radar signals,frequency agility,and variable pulse width signals.Therefore,the main research contents of this article are as follows:1.Firstly,the traditional threshold setting of CDIF cannot be reasonably adjusted according to the signal environment.During the actual sorting process,PRIs that do not exist in the original electromagnetic environment may be detected,resulting in false alarms.To solve this problem,an adaptive threshold setting method based on CDIF is proposed.The basic idea is to first derive a probability model for the time difference between any two pulses in mixed radar signals falling into the PRI box through double integration;Then this model is combined with the probability distribution model of the arrival time of random mixing emitter pulses derived based on Poisson distribution,and the minimum statistical threshold that must be met by the time difference between all pulses is derived,which is defined as the noise threshold to reduce the false alarm probability;Finally,based on the noise threshold,the adaptive threshold of CDIF is derived,and the adaptive adjustment of the threshold is achieved.Secondly,a variable overlapping PRI box is used in the CDIF method to improve the sorting ability of the CDIF method for jitter radar signals.Finally,in order to improve the sorting ability of the improved CDIF method for large jitter radar signals,a comprehensive radar signal sorting method combining the improved CDIF and PRI transform is proposed,which improves the sorting ability of large jitter radar signals.2.When clustering Parameter agile radar signals,radar signals from the same radiation source will be divided into different signal clusters,resulting in additional batches.To solve this problem,based on the previously proposed comprehensive sorting method for radar signals,an anti increment batch method for sorting agile radar signals is proposed.The basic idea is to first traverse each cluster of signals after clustering,and use a radar signal comprehensive sorting method to obtain PRI information for each cluster of signals;Based on the obtained PRI information,all signal clusters from the same radiation source in the electromagnetic space are merged to ensure the accuracy of cluster merging.3.In order to solve the problems of low sorting accuracy and long sorting time in complex electromagnetic environments using traditional radar signal sorting methods,a radar signal batch processing sorting method combining data fields and sliding windows is proposed.Firstly,a data field is used to denoise the mixed radar signals,and the radar signals are intercepted through a sliding window.The signals in the window are stored in the radar signal sorting transient library.When the quantity of signals in the radar signal sorting transient library has reached the clustering threshold,the signals in the radar signal sorting transient library are clustered and the radar signal sorting transient library is cleared;Afterwards,the signal clusters whose signal quantity has not reached the sorting threshold are stored in the radar signal sorting transient library.For the signal clusters whose signal quantity has reached the sorting threshold,the anti increment batch method is first used to merge the signal clusters from the same radiation source,and then the main sorting method is used for sorting.The sorted signals are stored in the sorted radar signal library,and the sliding window is continuously moved;Finally,when the window moves to the end point,the signals stored in the sorted radar signal library are traversed to merge radar signals from the same radiation source.Through simulation experiments,this paper confirms that the proposed method has better sorting accuracy and shorter sorting time compared to traditional radar signal sorting methods in complex electromagnetic environments.