Patent ID: 7440762
Filing Date: 2008-10-21
Classification: G01S,H04W

Abstract:
1. A system for the determination of the location of a mobile station (MS) equipped with embedded GPS signal reception capability and equipped to operate within a wireless communications network based on the Global System for Mobile communications (GSM), the system comprising position-determination equipment (PDE) including: a plurality of location measurement units (LMUs) each of which is embedded at a networked land station (LS) for signal detection and processing, wherein each LMU is connected to and receives signals from a GPS antenna and from wireless communications band antenna(s); a serving mobile location center (SMLC) at a central collection-and-analysis land station (LS), said SMLC being configured to assemble measurements from the LMUs and to calculate the MS location; and a location gateway (LG) at the central land station configured to receive location requests from a mobile positioning center (MPC) specifying the identity and serving cell assignment data for a MS of interest, said location gateway providing a PDE portal for the reception of location requests and for provision of location-determination results to the MPC; wherein the system is programmed and configured to perform the following steps: a request for the location of a particular MS of interest originating at the MPC is received at the LG, and the LG validates the authenticity and authorization for the location request, wherein a valid request identifies the serving cell and associated communications protocol parameters, including assigned frequency, that shall apply for the communications with the MS; the LG provides the request to the SMLC appropriate for the determination of locations for MSs operating in the vicinity of the serving cell; the selected SMLC receives and reviews any request to determine the list of cooperating LMUs that are optimal for supporting location requests associated with the identified serving cell; in anticipation of the need to rapidly support a request for assisting GPS data, the SMLC maintains and evaluates current GPS configuration data that specify the location and motion parameters for the GPS satellite vehicles (SVs), wherein these data are persistently monitored by the LMUs through their GPS receivers, and wherein the LMUs provide to the SMLC the Doppler shifts, pseudoranges, and relevant demodulated navigation message data for the GPS SV telemetry streams received at the LMU positions; the SMLC receives these GPS SV data periodically communicated from the LMUs, and for each potential serving cell, the SMLC evaluates and derives a current list that specifies the optimal SVs in potential view near the cell site, along with the restricted domains of Doppler shift and pseudorange that are anticipated to be appropriate for assisting in an AGPS reception; and in order to exploit the availability of the up-to-date descriptions of the GPS configuration parameters to support a reduced time to first fix (TTFF) from the MS GPS receiver, the SMLC responds to a particular location request and provides the AGPS parameters appropriate for the vicinity of the serving cell site, wherein these AGPS parameters are received by the LG and are provided to the MPC to be communicated to the MS in a GPS data request.