Patent ID: 6285321
Filing Date: 2001-09-04
Classification: G01S,H04W,Y02D

Abstract:
A station-based method for use in a wireless location system to determine the geographic location of a mobile wireless transmitter, the wireless location system including signal collection systems and location processors for processing digital data provided by the signal collection systems, the method comprising:a) receiving a transmission from a wireless transmitter at multiple antennas and at multiple signal collection systems;b) converting the transmission into a digital format in a receiver connected to each antenna at the multiple signal collection systems;c) at each signal collection system, storing digital data representative of the received transmissions in a memory in the signal collection system;d) demodulating the transmission at a first signal collection system and determining appropriate phase correction intervals;e) at the first signal collection system, for each such phase correction interval calculating appropriate phase correction parameters, and encoding the phase correction parameters along with the demodulated data;f) sending the demodulated data and phase correction parameters from the first signal collection system to a location processor;g) at the location processor, determining the signal collection systems and receiving antennas to use in location processing;h) sending the demodulated data and any needed phase correction parameters from the location processor to a plurality of signal collection systems that will be used in location processing;i) at each signal collection system to be used in location processing, creating a first re-modulated signal based upon the demodulated data and any needed phase correction parameters;j) at each signal collection system to be used in location processing, performing a time difference of arrival (TDOA) determination using the digital data stored in memory and the first re-modulated signal;k) sending the TDOA and multipath mitigation data from the signal collection systems to the location processor; andl) at the location processor, determining the location of the wireless transmitter using the TDOA data.