GPS satellite signal acquisition assistance system and method in a wireless communications network

• US 7,254,402 B2
• Filed: 07/20/2001
• Issued: 08/07/2007
• Est. Priority Date: 10/12/2000
• Status: Expired

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Agashe, Parag, Soliman, Samir, Gaal, Peter, Stein, Jeremy, Vayanos, Alkinoos, Fernandez-Corbaton, Ivan Jesus
• Primary Examiner(s): Anderson; Matthew D.
• Assistant Examiner(s): TRINH, TAN H
• Application Number:
  US09/910,361
• Publication Number:
  US 20020123352A1
• Time in Patent Office: 2,209 Days
• Field of Search: 455/456, 455/457, 455/561, 455/427, 455/502, 455/456.1, 455/456.3, 455/440, 455/404.2, 455/67.16, 342/357.15, 342/357.1, 342/463, 342/357.06, 342/357.01, 342/357.09
• US Class Current: 455/456.1
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset
• CPC Class Codes: H04B 2201/70715 with application-specific features

Abstract

A system and method for assisting an integrated GPS/wireless terminal unit in acquiring one or more GPS satellite signals from the GPS satellite constellation. The invention includes a method for narrowing the PN-code phase search. That is, by accounting for the variables in geographic location and time delay relative to GPS time, the systems and methods of the present invention generate a narrow code-phase search range that enables the terminal unit to more quickly acquire and track the necessary GPS satellites, and thereby more quickly provide accurate position information to a requesting entity.

Claims

1. A system for transmitting a GPS receiver code-phase search range to a integrated GPS/wireless terminal unit operating in a wireless network, said system comprising:

a receiver operable to generate a GPS time reference;

a controller operable to calculate a GPS code-phase search range with reference to a base station geographic location, the wireless coverage area, an angle between a vector extending from the base station to a GPS satellite and a vector extending from the base station to the GPS/wireless terminal unit, said GPS time reference and the estimated wireless signal propagation delay within said coverage area, and

a transmitter coupled to said controller and operable to transmit said calculated GPS code search range.

2. The invention of claim 1 wherein said GPS code-phase search range is defined by a center value and a size value.

3. A system for transmitting a GPS receiver code-phase search range to a integrated GPS/wireless terminal unit operating in a wireless network, comprising:

a GPS receiver operable to generate a GPS time reference;

means for obtaining a time offset for the GPS/wireless terminal unit relative to said GPS time reference;

a controller operable to calculate a GPS code-phase search range with reference to a base station geographic location, a radius of the wireless coverage area served by the base station, an elevation angle of a GPS satellite, and said time reference; and

a transmitter coupled to said controller and operable to transmit said calculated GPS code search range.

4. The invention of claim 3 wherein said GPS code-phase search range is defined by a center value and a size value.

5. The invention of claim 3 wherein said means for obtaining a time offset utilizes the round-trip wireless signal propagation time between said base station and the terminal unit to establish said time offset.

6. A system for transmitting a GPS receiver code-phase search range to a integrated GPS/wireless terminal unit operating in a wireless network, comprising:

a GPS receiver operable to generate a GPS time reference;

means for obtaining a time offset for the GPS/wireless terminal unit relative to said GPS time reference;

means for obtaining a location reference for the GPS/wireless terminal unit;

a controller operable to calculate a GPS code-phase search range with reference to a variance of a positioning error of said location reference, and said time reference; and

a transmitter coupled to said controller and operable to transmit said calculated GPS code search range.

7. The invention of claim 6 wherein said GPS code-phase search range is defined by a center value and a size value.

8. The invention of claim 6 wherein said means for obtaining a location reference utilizes means for providing terrestrial based trilateration to establish said location reference.

9. A method for defining a GPS receiver code-phase search range for an integrated GPS/wireless terminal unit operating in a wireless network having a base station comprising the steps of:

calculating a GPS code-phase search range with reference to the base station geographic location plus the wireless coverage area, an angle between a vector extending from the base station to a GPS satellite and a vector extending from the base station to the GPS/wireless terminal unit, and with reference to a base station GPS time reference plus the estimated wireless signal propagation delay within said coverage area and

transmitting said calculated GPS code-phase search range.

10. The invention of claim 9 wherein said GPS code-phase search range is defined by a center value and a size value.

11. A method for defining a GPS receiver code-phase search range for an integrated GPS/wireless terminal unit operating in a wireless network having a base station, comprising the steps of:

obtaining a time reference for the GPS/wireless terminal unit establishing the time offset relative to the base station GPS time;

calculating a GPS code-phase search range with reference to the base station geographic location plus a radius of the wireless coverage area served by the base station, an elevation angle of a GPS satellite, and said time reference; and

transmitting said calculated GPS code-phase search range.

12. The invention of claim 11 wherein said GPS code-phase search range is defined by a center value and a size value.

13. The invention of claim 11 wherein said obtaining step utilizes the round-trip wireless signal propagation time between said base station and the terminal unit to establish the time offset.

14. A method for defining a GPS receiver code-phase search range for an integrated GPS/wireless terminal unit operating in a wireless network having a base station, comprising the steps of:

obtaining a time reference for the GPS/wireless terminal unit establishing the time offset relative to the base station GPS time;

obtaining a location reference for the GPS/wireless terminal unit;

calculating a GPS code-phase search range with reference to a variance of a positioning error of said location reference, and said time reference; and

transmitting said calculated GPS code-phase search range by the base station.

15. The invention of claim 14 wherein said GPS code-phase search range is defined by a center value and a size value.

16. The invention of claim 14 wherein said obtaining a location reference step utilizes terrestrial based trilateration techniques to establish said location reference.

17. A system for transmitting a GPS receiver code-phase search range to an integrated GPS/wireless terminal unit operating in a wireless network, said system comprising:

a receiver operable to generate a GPS time reference;

a controller operable to calculate the GPS code-phase search range with reference to a base station geographic location, a position estimate of the integrated GPS/wireless terminal unit having an uncertainty area with a center distinct from the base station geographic location, and said GPS time reference; and

a transmitter coupled to said controller and operable to transmit said calculated GPS code-phase search range.