Cell organization and transmission schemes in a wide area positioning system (WAPS)

摘要

A position location system comprises transmitters that broadcast positioning signals. Each broadcasted positioning signal comprises a pseudorandom ranging signal. The position location system includes a remote receiver that acquires and measures the time of arrival of the positioning signals received at the remote receiver. During an interval of time, at least two positioning signals are transmitted concurrently by the transmitters and received concurrently at the remote receiver. The two positioning signals have carrier frequencies offset from one another by an offset that is less than approximately twenty-five percent of the bandwidth of each positioning signal of the two positioning signals. Cross-interference between the positioning signals is reduced by tuning the remote receiver to a frequency of a selected signal of the two positioning signals and correlating the selected signal with a reference pseudorandom ranging signal matched to a transmitted pseudorandom ranging signal of the selected signal.

主权项

1. A position location system comprising:
a plurality of transmitters, each of the plurality of transmitters are at different locations and are operable to transmit a positioning signal that includes a pseudorandom ranging signal modulated on a carrier having one carrier frequency selected from a finite set of values, the plurality of transmitters including two transmitters that are operable to concurrently transmit two positioning signals, a first of the two transmitters operable to transmit a first of the two positioning signals that includes a pseudorandom ranging signal modulated on one carrier having a first carrier frequency, and a second of the two transmitters operable to transmit a second of the two positioning signals that includes a pseudorandom ranging signal modulated on one carrier having a second carrier frequency that is offset from the first carrier frequency by an offset that is less than or equal to twenty-five percent of the bandwidth of each positioning signal of the two positioning signals.