A
system and method of determining and reporting on the position of a
wireless device relative to a group of other
wireless devices dispersed within a specified
geographic area. The
system includes at least one Query Unit, three or more Responding Units disposed at determinable locations within the specified
geographic area, and one or more Mobile Units, which may correspond to additional Responding Units or units that function only as receivers. The Query Unit sequentially queries the Responding Units, and, responsive to the respective query messages, the Responding Units transmit corresponding response messages. One or more of the Mobile Units receive the query and response messages, and generate, for each query-response message pair, a set of time-difference-of-arrival (TDOA) measurements, which are used by the Mobile Units to determine their positions relative to the Responding Units. The Mobile Units
record the times-of-arrival (TOAs) of the query message and the response messages at their respective receivers, and calculate the TDOAs based on the recorded TOAs. The TDOAs are then analyzed to determine the time differences due to the differences in lengths of the respective
message propagation paths. The position of each Mobile Unit can then be computed using computation techniques typically employed in Long Range Navigation (LORAN) receivers, or any other suitable computation technique.