A Low Cost Ultrasound-based Localisation System for Ground Robotics

Abstract

This paper presents a low-cost localisation system based on ultrasonic sensing and time of flight measurements. A compact ultrasound emitter has been designed to generate an omnidirectional train of ultrasound pulses which are then picked up by several fixed receivers measuring the time difference of arrival. A least squares approach is used to analytically obtain a first estimate of the emitter position, which is then refined through steepest descent optimisation. All processing is done via a standard Arduino platform, proving the low computational demands of the method. Localisation results are validated against a state-of-the-art Optitrack motion capture system. It is shown that the system can cover a 4.3´3.1 m arena with a mean error localisation error of 1.57 cm and an average standard deviation of 1.39 cm throughout the arena. The effectiveness of the proposed localization system is demonstrated by integrating it with a mobile ground robot to enable waypoint-based path following.

Keywords

• localisation
• ultrasound
• time difference of arrival
• positioning
• ground robots