A parallel processing solution to ESM

The Admiralty Research Establishment (ARE) is responsible for developing ESM signal processing algorithms capable of detecting and identifying radar emitters in complex, high density naval scenarios. An important processing stage in the algorithms is to assemble individual pulses from each emitter into pulse chains. This process is termed deinterleaving. The performance of the deinterleaver in processing complex radar waveforms in a high pulse density environment is fundamental to the reliable operation of the entire ESM system. ARE has developed a sophisticated deinterleaver (termed DIF6) which operates in two stages. Firstly, pulses are merged into clusters formed from the basic pulse measurements. Secondly, the time differences between pulses in each cluster are used to form a time of arrival difference (ToAD) histogram. Signals which may be overlapped in pulse repetition interval are detected by locating peaks in the ToAD histogram and gated from the input data. Several iterations of this process may be required to detect all pulse chains. The deinterleaver then forms a characterised pulse chain which is output to other processing stages in the ESM signal processor