ENHANCING A-GPS LOCATION ACCURACY AND YIELD WITH LOCATION MEASUREMENT UNITS AND NETWORK TIMING MEASUREMENTS

• US 20140307575A1
• Filed: 06/24/2014
• Published: 10/16/2014
• Est. Priority Date: 11/16/2011
• Status: Active Grant

• Current Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Original Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Inventors: Al-Mufti, Khalid W., Kalenahalli, Suryanarayana A.
• Granted Patent: US 9,456,304 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 64/003 locating network equipment
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination

Abstract

A system and method for determining the location of a mobile device. One or more location measurement units (LMUs) or components may be requested to provide timing relationship information from a respective cell site. These LMUs may then be tasked to measure uplink times of arrival of signals received by the LMUs from a target mobile device. A response message from the target mobile device may be received, the response message having reference epoch frame information whereby a Global Positioning System (GPS) time estimate at the reference epoch that the target mobile device used to make GPS satellite measurements is determined as a function of the requested timing relationship information. Satellite information may then be determined using the determined GPS time estimate, and a location of the mobile device performed using this satellite information.

Claims

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

(a) 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;

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

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

(d) 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;

(e) determining satellite information using the determined GPS time estimate; and

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

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

(i) receiving a location request by the node for a target mobile device; and

(ii) transmitting a request message to the target mobile device in response to the location request.

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

4. The method of claim 2 wherein the request message includes GPS time assistance measurement request elements.

5. The method of claim 2 wherein the location request includes one or more of tipping information for the target mobile device, uplink signal radio frequency information, and serving site identification.

6. The method of claim 2 further comprising the steps of:

(iii) receiving the position request by the target mobile device; and

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

7. 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.

8. 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).

9. 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.

10. The method of claim 1 wherein the determined GPS time estimate is determined using the relationship:

t<sub>RFGPS—

MS</sub>=t<sub>RFGPS—

LMU</sub>+τ

_p

where t<sub>RFGPS—

LMU</sub> 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.

11. 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.

12-30. -30. (canceled)

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

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

(b) measuring uplink times of arrival of signals from a target mobile device;

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

(d) 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;

(e) determining satellite information using the determined GPS time estimate; and

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

32-33. -33. (canceled)