Patent ID: 6300899
Filing Date: 2001-10-09
Classification: G01S,H04B

Abstract:
A method for determining position fix by interpreting a plurality of broadcasted GPS signals comprising the steps of:receiving the plurality of broadcasted GPS signals and providing a digitized signal dependent thereon;correlating a first-portion of the digitized signal to a code replica and determining a real-time code phase delay;determining a Time Of Arrival (TOA) of a deterministic portion of the digitized signal, dependent on the determined real-time code phase delay;determining a capture start time dependent on the TOA;receiving a reference code phase delay and a reference Doppler shift, from a fixed position reference site;capturing a second portion of the digitized signal into a memory commencing coincident with the determined capture start time;identifying a reduced code replica search space dependent on the received reference code phase delay and reference Doppler shift; andextracting the second portion of the digitized signal from the memory and correlating the extracted signal to the reduced code replica search space and determining an off-line code phase delay.