Patent ID: 7573423
Filing Date: 2009-08-11
Classification: G01S

Abstract:
1. A method of acquisition of satellite data by a mobile device including a radio navigation satellite system (RNSS) receiver, said method comprising: receiving a signal transmitted by a plurality of satellites and corresponding to a sum of signals each transmitted by a satellite and each modulated by a spread spectrum signal characteristic of said satellite; generating a plurality of local duplicates each of which is the duplicate of a spread spectrum signal characteristic of a satellite; correcting a frequency of each of said local duplicates by compensating a Doppler effect of each of said satellites using assistance data sent by an assistance server to said mobile device; summing the corrected duplicates; determining a correlation function as a function of time between the sum of the corrected duplicates and said satellite data signal; and identifying each of the satellites associated with each of correlation peaks revealed by said correlation function, wherein, after the at least one satellite has been identified, each remaining satellite is identified, using assistance data sent to said mobile device from an assistance server, said assistance data including ephemerides of said plurality of satellites and an identifier of a cell in which said mobile device is located, by determining a propagation time difference of a signal between the at least one satellite already identified and said mobile device, on the one hand, and each of the remaining satellites to be identified and said mobile device, on the other hand.