High resolution distance sensing for mini-robots using Time Difference of Arrival

This paper presents an efficient, compact, and robust distance-only sensor for networked small robotic platforms with wireless communication and signal processing capabilities. The sensor determines inter-robot distances by measuring the Time Difference of Arrival (TDOA) between wireless radio frequency packets and audio pulses. Computational overhead has been reduced by an order of magnitude while the sensor resolution has been improved to 0.27 cm over a range of 75 cm, compared to a previous resolution of 1.1 cm. Error analysis identified timing jitter as the dominant contribution to measurement error and a significant factor in heading estimation error using distance-only measurements. The improvement in distance resolution is shown to improve system performance by reducing the motion planning decision error rate due to measurement uncertainty.