Network Optimization for Multistatic Ultrasonic Sensors Based Indoor Navigation System

This paper presents a novel indoor navigation technique using acoustic sensors, with emphasis on performance modelling and the system layout optimisation. Acoustic transmitters are arranged at known fixed locations and broadcast their respective signals following a Time Division Multiple Access (TDMA) scheme. The receiver position is calculated based on ranging measurements from a minimum of four transmitters. The range is calculated based on time-of-flight (TOF) of acoustic waves from the transmitter to the receiver. The transmitters are arranged optimally to minimize Position Dilution of Precision (PDOP). Optimizing the location of transmitters for minimum PDOP also leads to better coverage in the indoor environment, where conventional satellite based navigation systems cannot deliver the required Position, Velocity and Time (PVT) data. The attenuation of sound in air is discussed along with potential ranging errors and signal delays. Simulations are carried out to optimize the arrangement of transmitters for future experiments with indoor air and surface vehicles.