Improved method for deinterleaving radar signals and estimating PRI values

In the electronic countermeasure, the electronic support measure (ESM) receiver intercepts the interleaved radar pulse streams, which radiates from surrounding radar emitters. At present, deinterleaving algorithm based on time of arrival which is called pulse repetition interval (PRI) deinterleaving occupies an important part of the ESM. The sequential difference histogram (SDIF) is a well-known and effective PRI deinterleaving algorithm, but it has several disadvantages. When the PRI jitter and pulse missing exist in the pulse streams, the SDIF algorithm cannot estimate the real PRI value reliably, and then cannot separate the radar pulse trains corresponding to the real PRI value from the interleaved pulse streams. In order to overcome these disadvantages, an improved SDIF algorithm using clustering algorithm and PRI transform is proposed. Simulation results have proved that this improved algorithm has higher reliability and accuracy in the presence of PRI jitter and pulse missing.