ULTRASOUND-BASED LOCATION DETERMINATION AND INERTIAL NAVIGATION WITH ACCURACY IMPROVEMENT IN DETERMINING CLIENT DEVICE LOCATION

摘要

Spatially located ultrasound beacons are provided in known locations within a distributed communication system. The ultrasound beacons are configured to emit ultrasound pulses that can be received by client devices in ultrasound communication range of the beacons. The client devices analyze the received ultrasound pulses from the beacons to determine their time-difference of arrival and as a result, their location(s) within the distributed communication system. The client devices have inertial navigation systems (INS) that calculate client device location as the client device moves, and when received ultrasound signals are below a predefined threshold. Suspected errors in the location information from either the ultrasound or INS systems may be compared against the other system, or compared against reference information, to determine the validity of the location information.