Localized high-accuracy railcar tracking system with a lowpower time-difference technique

摘要

A system for determining location of an object within a defined area includes at least three object-locating receivers situated at predetermined locations about the area. A transmitter affixed to the object emits a signal which is received by the receivers such that at least two time difference of arrival (TDOA) values are determined between the receivers in each of at least two respective pairs of the receivers. Each of the TDOA values defines a respective curve such that the defined curves intersect. The intersection of the curves identifies the location of the object within the defined area. A time reference for determining each of the TDOA values may be obtained from global positioning system (GPS) receivers co-located with each of the object-locating receivers. IMAGE