Bionic SONAR Head

The work done on the bionic SONAR head has a dual purpose: 1. to provide a platform from which to investigate the real-time information processing tasks carried out by biological systems -- i.e., echolocating bats; 2. to engender artificial navigation systems with some of the sophisticated performance and robustness of those biological systems.

Approach:

The bionic SONAR head operates by transmitting a structured call, FM-sweep or CW-pulse, and picking up echoes with a pair of steerable receivers. The raw echo signals are first transformed by a simple model of the bat's cochlea. Next the information from both ears is combined to arrive at estimates of the 3D position of targets. We are exploring the following binaural localisation algorithms:

• The interaural intensity differences between the echoes arriving at ears positioned with fixed elevation offsets.
• Differences in the amplitude modulation patterns of the echoes due to active steering of the ears.
• Doppler shift differences, brought about by continuous self motion as well as reflector motion.
• The time differences between the echoes arriving at both ears -- i.e., interaural time differences and monaural time differences between the direct and the secondary echo, reflected upon the pinna.