On-the-fly classifying sonar with accurate range and bearing estimation

This paper presents results from a four transducer pulse coded sonar system that performs target localisation in two dimensions and classification into planes, concave corners and convex edges whilst the sensor is in motion. On each sensing cycle two pulses are emitted from separate transmitters, and two receivers collect echoes that are processed using a DSP. The sensor achieves on-the-fly classification by transmitting nearly and simultaneously from the two transmitters. The effects of sensor motion are analysed in the paper and effects on range and bearing estimation can then be compensated using odometry based robot velocity measurements. Results are presented that show classification and angle measurement deviations from a robot moving at speeds up to 1 metre per second.