초록 ▼

The intention of the invention is to produce a network-based Wireless Location System (WLS) whereby existing Advanced Mobile Phone System (AMPS) Frequency Division Multiple Access (FDMA) Cellular Telephones (CTs) can be located passively without modification to the CTs or to the cellular antenna inf

The intention of the invention is to produce a network-based Wireless Location System (WLS) whereby existing Advanced Mobile Phone System (AMPS) Frequency Division Multiple Access (FDMA) Cellular Telephones (CTs) can be located passively without modification to the CTs or to the cellular antenna infrastructure. More specifically, the invention consists of methods and apparatus to estimate the position and velocity of a Cellular Telephone (CT) using either the Time Of Arrival (TOA) of a signal transmitted by the CT, its Phase Of Arrival (POA), its Frequency Of Arrival (FOA), or a combination thereof, at several antennas at a number of Monitoring Sites (MSs). In order to solve for the coordinates of the CT, the patent uses either hyperbolic multilateration based on Time Difference Of Arrival (TDOA), or linear multiangulation based on Phase Difference Of Arrival (PDOA), or both. In order to solve for the velocity of the CT, the patent uses FOA based on Frequency Difference Of Arrival (FDOA). An important contribution of this invention is the way the CT is forced to transmit radio signals for location purposes. Another important contribution is the application of Super-Resolution (SR) techniques to increase the resolution of the estimated TOAs, POAs or FOAs.

대표청구항 ▼

[ We claim:] [1.]1. A method of estimating the location of a cellular telephone that is initiating a call, the method comprising the steps of:monitoring the initiation of the call over a reverse control channel using a first monitoring site;monitoring a reverse voice channel assignment over the corr

[ We claim:] [1.]1. A method of estimating the location of a cellular telephone that is initiating a call, the method comprising the steps of:monitoring the initiation of the call over a reverse control channel using a first monitoring site;monitoring a reverse voice channel assignment over the corresponding forward control channel using the first monitoring site;notifying a plurality of monitoring sites to monitor the signal s(t) generated by the cellular telephone over the assigned reverse voice channel during an observation time T which coincides with the cellular telephone being in either answered conversation mode or unanswered conversation mode;processing the signal s(t) by each one of the plurality of monitoring sites by estimating the phase of one of a SAT tone resolved using superresolution algorithms and a tone derived from the pitch of the signal s(t) and resolved using superresolution algorithms;estimating the location of the cellular telephone from the estimated phase to generate a location estimate; andtransferring the location estimate to a user during unanswered conversation mode.