New processing techniques for ESM using partial coherence

The trend in naval scenarios towards greater complexity in radar signals and high duty cycle transmissions both from own ship and from the signal environment of interest puts even greater demands on the receiver and signal processing of ESM systems. In particular, a growing need exists for large dynamic range, wide bandwidth and high frequency-resolution systems that have the ability to automatically identify a wide range of threats. Optical arrangements based upon acousto-optical (AO) Bragg cells are being investigated by many researchers because they offer the promise of high-speed processing, particularly in the form of spectrum analysers used for channelised receivers. This paper describes recent research at ARE on novel system designs using optical partial-coherence processing which shows that the currently observed limits are not fundamental and that optical arrangements do indeed offer potential not only as channelised receivers, but as powerful signal processing systems