Patent ID: 8004464

Claim:
A method of determining the positions of a plurality of objects by processing signals emitted from at least one transmitter, reflected by the objects and received by a plurality of receivers, the method comprising: processing signals from the receivers to generate a respective object-receiver pair time difference of arrival measurement for each object and each pair of receivers comprising the time difference of arrival between the signals received at each of the receivers in the pair from the object; processing the generated object-receiver pair time difference of arrival measurements to calculate a respective hyperbola for each object and each pair of receivers with the positions of the receivers as foci points and the hyperbola defining the set of possible positions for the object; calculating the intersections of the generated hyperbolae and identifying the intersections corresponding to possible positions for each individual object, wherein each possible position is either a true position or a phantom position; processing signals from the receivers to generate a direct-reflected signal time reception measurement for each receiver-object pair comprising the time difference between the reception by the receiver of the direct signal from the transmitter and the reception by the receiver of the signal reflected by the object; associating the generated direct-reflected signal time reception measurements with the generated object-receiver pair time difference of arrival measurements to generate measurement association results; and determining the true positions of the objects by relating the calculated intersections of the generated hyperbolae to the generated direct-reflected signal time reception measurements using the measurement association results.