Biologically inspired processing of target echoes

Echolocating bats have evolved an impressive ability to detect and discriminate targets in highly challenging environments. It is believed that over 50 million years of evolution have contributed to optimize their echolocation system so that highlevel performance could be achieved within their operating environment. The way bats interrogate the surroundings present differences, as well as similarities, with respect to typical signal processing techniques used in synthetic sensors. In identifying and investigating these differences, useful lessons can be made available to engineers that can potentially be used to improve radar and sonar systems. In this chapter, we review some of the strategies that bats are believed to employ to detect and classify moving and static targets and present a comparison with the radar and sonar counterparts. We introduce a baseband receiver based on an existing model of the bat auditory system and apply it to baseband synthetic ultrasound signals to investigate target detection and resolution performance. Chapter Contents: Abstract • 7.1 Introduction • 7.1.1 Detection and identification of stationary targets - flowers • 7.1.2 Detection and identification of moving targets - insects • 7.1.3 Comparison between radar, sonar and biological systems • 7.2 The need for a receiver model • 7.3 Description of the spectrogram correlation and transformation model • 7.3.1 Cochlear block • 7.3.2 Temporal block • 7.3.3 Spectral block • 7.4 Baseband equivalent of the spectrogram transformation • 7.5 Experimental setup to compare BSCT and SCAT • 7.5.1 Data collection and digitization • 7.5.2 Targets and echo • 7.5.3 Data processing • 7.6 Results • 7.7 Conclusion • References.