Band Limited Pulse Encoding and Signal Classification

Torpedo sonar systems will soon be capable of operating over much wider bandwidths than previously possible, enabled by technology insertions with improved transducers, T/R electronics, and signal processors. The proposed research investigates the use of a class of wideband acoustic waveforms to reduce the vulnerability to echo-repeater decoys while maintaining full sensitivity against actual targets of interest. Waveforms are proposed which provide unambiguous range response over time delays of at least 10 seconds, countering decoys which replay prior pulses to simulate range pull-in effects. The proposed waveforms also feature dynamically-scheduled frequency hopping, designed to minimize predictability and detectability. An assessment of computational complexity for the associated detection processing is included in the proposed research effort, covering both fully-coherent wideband processing and a semi-coherent pulse processing method for reduced compute load.