Patent ID: 6249253
Filing Date: 2001-06-19
Classification: G01S,H04B

Abstract:
A method for determining a location of a radiotelephone comprising a pilot signal receiver, a global positioning system (GPS) signal receiver, and a local clock, the radiotelephone operating in a radiotelephone system comprising a plurality of bases stations, each base station comprising a pilot signal transmitter and a GPS signal receiver, the method comprising the steps of:estimating a time of arrival of GPS signals at the radiotelephone GPS receiver relative to the radiotelephone clock;estimating a time of arrival of a radiotelephone system pilot signal at the radiotelephone signal receiver relative to the radiotelephone clock; andcalibrating the time of arrival values in response to delays associated with the base station's pilot signal transmitter and the radiotelephone's pilot signal receiver.