Efficacy of up and down-chirps for two-pulse sonar techniques

Twin-Inverted Pulse Sonar (TWIPS) and Biased Pulse Summation Sonar (BiaPSS) were inspired by a video of dolphins using bubble nets to hunt. There are a number of animals that have been observed to use the chirp (a sweep in sine waves of shifting frequency) in echolocation. This talk will present the difference in efficacy of the sonar techniques, mentioned above, when using upwards and downwards sweeping chirps as sonar signals. These techniques have been simulated and experimentally tested with a number of bubble size distributions (BSD). This includes simulations using the results of BSD measurements by Farmer and Vagle (1989). Further, another two-pulse technique will be outlined, proposed as a means to overcome the limitation on detection range, owing to the inter-pulse delay in TWIPS and BiaPSS.