Fast target classification using sonar

This paper describes a new sonar system that can perform target localisation in two dimensions and classification into planes, concave corners and convex edges with no extra time overhead, that is, the sensor transmits on two transmitters a short time apart, thereby collecting echoes in virtually the same time as a single transmitter of the system. Moreover, the time separation of the transmitted pulses acts to identify the particular sonar system so that interference from other systems can be rejected. The sensor combines two previous sonar research efforts on double pulse coding and classification in a real time DSP-based sensing module that is also smaller than previous sensors. Since the classification is performed with such a short delay between transmitter firings, the sensor can be deployed on moving platforms to achieve on-the-fly mapping. This paper describes the sonar hardware, maximum likelihood estimation classification approach and experimental results