SYSTEM AND METHOD FOR PREVENTING A-GPS DEVICES FROM SEARCHING FOR SPECIFIC SATELLITES

• US 20090146877A1
• Filed: 04/09/2008
• Published: 06/11/2009
• Est. Priority Date: 12/07/2007
• Status: Active Grant

• Current Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Original Assignee: Commscope Inc of North Carolina (CommScope Holding Company, Inc.)
• Inventors: Harper, Neil, Thomson, Martin
• Granted Patent: US 8,085,193 B2
• Time in Patent Office: Days
• US Class Current: 342/357.430
• 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 19/20 Integrity monitoring, fault detection or fault isolation of space segment
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
• CPC Class Codes: G01S 19/28 Satellite selection

Abstract

A system and method for estimating the location of a wireless device. A set of satellites may be determined as a function of an approximate area in which the wireless device is located. Assistance data is transmitted to the device including information from the set of satellites, and a location of the device may be estimated from the information where the assistance data prevents the wireless device from searching for signals from one or more satellites in the set of satellites. The one or more satellites may be an operable satellite but signals therefrom cannot be measured or acquired by the wireless device.

Claims

1. A method for estimating the location of a wireless device comprising the steps of:

(a) determining a set of satellites as a function of an approximate area in which the wireless device is located;

(b) transmitting assistance data to said device, said assistance data including information from said set of satellites; and

(c) estimating a location of the device from said information,

wherein said assistance data prevents the wireless device from searching for signals from one or more satellites in said set of satellites.

2. The method of claim 1 wherein said assistance data is Real Time Integrity assistance data.

3. The method of claim 1 wherein said one or more satellites is an operable satellite but signals therefrom cannot be measured or acquired by said device.

4. The method of claim 1 wherein the estimated location of the device is a function of signals provided by a cellular network.

5. The method of claim 1 wherein the satellites are part of a Global Navigation Satellite System (“

GNSS”

).

6. The method of claim 5 wherein the GNSS is selected from the group consisting of:

Global Positioning System (“

GPS”

), Galileo, GLONASS, and Quasi-Zenith Satellite System (“

QZSS”

).

7. The method of claim 1 wherein the wireless device is selected from the group consisting of:

cellular device, text messaging device, computer, portable computer, vehicle locating device, vehicle security device, communication device, and wireless transceiver.

8. The method of claim 1 wherein the approximate area is selected from the group consisting of:

a serving area of a base station serving said wireless device, an approximate area of a communications network, city, municipality, county, state, country, and continent.

9. A system for determining a location of a device from signals received from a plurality of Global Navigation Satellite System (“

GNSS”

) satellites comprising;

(a) circuitry for determining a set of satellites as a function of an approximate area in which a device is located;

(b) a transmitter for transmitting assistance data to said device, said assistance data including information from said set of satellites; and

(c) circuitry for estimating a location of the device from said information,

wherein said assistance data prevents the wireless device from searching for signals from one or more satellites in said set of satellites.

10. The system of claim 9 wherein said assistance data is Real Time Integrity assistance data.

11. The system of claim 9 wherein said one or more satellites is an operable satellite but signals therefrom cannot be measured or acquired by said device.

12. The system of claim 9 wherein the GNSS is selected from the group consisting of:

Global Positioning System (“

GPS”

), Galileo, GLONASS, and Quasi-Zenith Satellite System (“

QZSS”

).

13. The system of claim 9 wherein the wireless device is selected from the group consisting of:

cellular device, text messaging device, computer, portable computer, vehicle locating device, vehicle security device, communication device, and wireless transceiver.

14. The system of claim 9 wherein the approximate area is selected from the group consisting of:

a serving area of a base station serving said wireless device, an approximate area of a communications network, city, municipality, county, state, country, and continent.