Method and apparatus for measurement processing of satellite positioning system (SPS) signals

DETAILED DESCRIPTION A method and apparatus for measurement processing of SPS signals is disclosed.
In one embodiment of the present invention, a plurality of GPS signals from a corresponding plurality of GPS satellites are received in a GPS receiver.
The signal environment corresponding to the location in which the GPS receiver is located is characterized to produce signal environment data.
In one exemplary embodiment, an information source, such as a cellular network based database, is searched to retrieve the signal environment data given an approximate location of the GPS receiver.
This approximate location may be specified by a location of a cell site which is in cellular radio communication with a cellular communication device which is co-located with the GPS receiver.
One or more parameters related to signal characteristics of the satellite signals are defined.
Threshold values for the parameters are determined using the signal environment data.
Code phases corresponding to times of arrival of respective satellite signals from the plurality of satellites are measured.
Data representing measured times of arrival are tested using threshold values for the parameters to produce a set of times of arrival from which a location solution for the GPS receiver is calculated.
In another embodiment of the invention, the signal environment corresponding to the location in which a GPS receiver is located is characterized to produce signal environment data.
This signal environment data reflects the manner in which SPS signals are propagated in the location.
The signal environment data is used to determine at least one processing value which is, in turn, used to process data representative of SPS signals received by the GPS receiver.
In one particular embodiment of the invention, a cell based information source (e.
g.
a cellular phone network based database) is used to determine a signal environment data which represents a manner in which SPS signals are propagated in a location at which an SPS receiver is located, and SPS signals by the SPS receiver at this location are processed in a manner specified by the signal environment data