P1G-3 Evaluation of a Bio-Inspired Range finding Algorithm (BIRA)

The ability of bats to orientate in the dark by employing complex sonic emissions has long held the fascination of scientists. It is known that some bats possess extremely sophisticated echo location capabilities, utilising chirp sequencing allied with an adaptive antenna system that enables extremely high resolution in 3-D space. One particularly interesting aspect is that bats appear to resolve and locate targets with scattering dimensions less than the wavelength of the emitted signals. They are also believed to identify the target shape by resolving multiple and closely reflecting points along the range axis. Properly harnessed, such techniques could possess significant potential for ultrasonic imaging. Modelling of the underlying processes of the bat has been covered in the literature, using a variety of approaches and geared mainly towards the study of how bats locate and capture flying insects. The current work involves the study of a ranging algorithm named BIRA (Bio-Inspired Range finding Algorithm), derived from the study of known bat auditory models. It investigates the performance of the algorithm in terms of resolution, robustness to noise and bandwidth requirement. The algorithm is shown to perform poorly in terms of implementation in practical ultrasonic systems. This represents an interesting finding in terms of bat behaviour and provides an indication that insect hunting bats may have evolved to use quite different methods for prey capture than those currently suggested in the literature