Enhancing A-GPS location accuracy and yield with location measurement units and network timing measurements

1. A method of determining the location of a mobile device comprising the steps of:

requesting by a node one or more location measurement units (LMUs) to provide timing relationship information from a respective cell site in a communications network;

receiving, at the node, a location request by the node for a target mobile device that includes at least one of tipping information for the target mobile device, uplink signal radio frequency information and serving site identification;

transmitting, from the node, a request message to the target mobile device in response to the location request;

tasking the one or more LMUs to measure uplink times of arrival of signals received by the LMUs from a target mobile device;

receiving a response message from the target mobile device, the response message having reference epoch frame information;

determining a Global Positioning System (GPS) time estimate at the reference epoch that the target mobile device used to make GPS satellite measurements, wherein the determination is performed as a function of the requested LMU timing relationship information;

determining satellite information using the determined GPS time estimate; and

determining a location of the mobile device as a function of the determined satellite information.

2. The method of claim 1 wherein the steps of transmitting a request message and tasking one or more LMUs are performed at substantially the same time.

3. The method of claim 1 wherein the request message includes GPS time assistance measurement request elements.

4. The method of claim 1 further comprising the steps of:

receiving the position request by the target mobile device; and

receiving signals from one or more satellites as a function of information in the position request, the information including a selected reference epoch.

5. The method of claim 1 wherein the step of receiving a response message further comprises receiving a response message from the target mobile device, the response message having reference epoch frame number information in a reference frame and having reference frame information elements.

6. The method of claim 1 wherein the node is selected from the group consisting of a serving mobile location center (SMLC), a standalone SMLC (SAS), and a radio network controller (RNC).

7. The method of claim 1 wherein the timing relationship information is selected from the group consisting of Global System for Mobile Communications-Global Positioning System Broadcast Channel (GSM-GPS BCCH) information and system frame network (SFN) information.

8. The method of claim 1 wherein the communications network is selected from the group consisting of a Universal Mobile Telecommunications System (UMTS) network, a Global System for Mobile Communication (GSM) network, a Time Division Multiple Access (TDMA) network, Code Division Multiple Access (CDMA) network, a Worldwide Interoperability for Microwave Access (WiMax) network, a WiFi network, CDMA2000 network, and a network utilizing Evolution-Data Optimized (EVDO), Long Term Evolution (LTE), or 1 times Radio Transmission Technology (1×RTT) standards.

9. A method of determining the location of a mobile device comprising the steps of:

requesting by a node one or more location measurement units (LMUs) to provide timing relationship information from a respective cell site in a communications network;

tasking the one or more LMUs to measure uplink times of arrival of signals received by the LMUs from a target mobile device;

receiving a response message from the target mobile device, the response message having reference epoch frame information;

determining a Global Positioning System (GPS) time estimate at the reference epoch that the target mobile device used to make GPS satellite measurements, wherein the determination is performed as a function of the requested LMU timing relationship information;

determining satellite information using the determined GPS time estimate; and

determining a location of the mobile device as a function of the determined satellite information;

wherein the determined GPS time estimate is determined using the relationship:

t

R

⁢

⁢

F

GPS_MS

=

t

R

⁢

⁢

F

GPS_LMU

+

τ

p

where

t

R

⁢

⁢

F

GPS_LMU

 represents the GPS-GSM or GPS-System timing relationship measured by the one or more LMUs and τ p represents propagation time from the mobile device to a serving cell.

10. A method of determining the location of a mobile device comprising the steps of:

receiving at a node timing relationship information from a respective cell site in a communications network;

receiving, at the node, a location request for a target mobile device that includes at least one of tipping information for the target mobile device, uplink signal radio frequency information and serving site information for the target mobile device;

transmitting a request message to the target mobile in response to the location request;

measuring uplink times of arrival of signals from the target mobile device;

receiving a response message from the target mobile device, the response message having reference epoch frame information;

determining a Global Positioning System (GPS) time estimate at the reference epoch that the target mobile device used to make GPS satellite measurements, wherein the determination is performed as a function of the received timing relationship information;

determining satellite information using the determined GPS time estimate; and

determining a location of the mobile device as a function of the determined satellite information.