Analysis and Evaluation of Sound-based Positioning Techniques for Short Distances

Sound-based positioning systems have shown a great potential in underwater and indoor applications. These systems are been used for robot tracking and navigation due to their simplicity and low cost. In fact, sound-based location techniques usually present acceptable positioning precision in obstacle-free wide areas due to the long wavelengths of sound signals. However, short-distance positioning is also useful for robot tracking and navigation, specially in the field o f m icro robotics. Nevertheless, sound-based positioning is not commonly applied in small areas because of the short propagation times. Hence, this work analyzes and evaluates experimentally typical trilateration techniques used for the positioning of targets through acoustic signals and low-cost hardware in distance-restricted environments. The long-term goal of this work is to make use of sound-based positioning techniques in micro robots for their tracking and navigation in small-scale areas. Obtained results show that the technique known as TDoA (time-difference of arrival) presents a good precision, generating errors as low as 1 cm in a 50×50 cm area.