PRF Sorting And PRF Tracking For ARM Seeker

Anti-Radiation-Missile(ARM)Seeker is a passive angular tracker,it receives and tracks the signal from an emitter.When the seeker operates in multiple signal environment,the line of sight of seeker will be wobbling among the emitters direction of arrival.In order to track the desired signal in stable,the sorting and identification processor should be built in the seeker.The functions of the processor are 1)measuring the signal parameters,especially the Pulse Repetition Interval(PRI)of desired signal,2)strobing the angular tracker at the predict time of arrival of desired signal.Several algorithms for estimating the PRI are present.In the paper,we compare their performance based on following requirements:processing time,the capability of eliminating subharmonics and the effect of missing pulse and interference to estimation of the PRI.The Sequence Difference Histogram(SDIF)algorithm is suggested in the seeker processor.After estimation of PRI,the PRI tracker(also called wheel tracker)is designed based on Complex Programmable Logic Device(CPLD).The PRI tracker generates a series of gate pulses at the same time of desired signals,and turns on the angular tracker.The experiment results show that the PRI tracker can track signals with constant,staggered PRI and PRI jittered signals with a ?PRI smaller than 10%of the average PRI.