Method and apparatus for determining time in a satellite positioning system

• US 6,433,731 B1
• Filed: 10/06/2000
• Issued: 08/13/2002
• Est. Priority Date: 02/03/1997
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc., Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Inventors: Krasner, Norman F., Sheynblat, Leonid
• Primary Examiner(s): Phan, Dao
• Application Number:
  US09/684,345
• Time in Patent Office: 676 Days
• Field of Search: 342/352, 342/357.06, 342/357.12, 342/357.13, 342/104, 701/213, 701/215
• US Class Current: 342/357.62
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/11 wherein the cooperating elements are pseudolites or satellite radio beacon positioning system signal repeaters
• CPC Class Codes: G01S 19/23 Testing, monitoring, correcting or calibrating of receiver elements
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: G01S 19/24 Acquisition or tracking or demodulation of signals transmitted by the system synchronisation aspects of direct sequence spread spectrum modulation H04B1/7073
• CPC Class Codes: G01S 19/246 involving long acquisition integration times, extended snapshots of signals or methods specifically directed towards weak signal acquisition
• CPC Class Codes: G01S 19/25 involving aiding data received from a cooperating element, e.g. assisted GPS
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: G01S 19/396 Determining accuracy or reliability of position or pseudorange measurements
• CPC Class Codes: G01S 19/42 Determining position
• CPC Class Codes: G01S 5/0009 Transmission of position information to remote stations involving assistance data G01S5/0236
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/0045 Transmission from base station to mobile station G01S5/009 takes precedence
• CPC Class Codes: G01S 5/0063 of measured values, i.e. measurement on base station and position calculation on mobile
• CPC Class Codes: G04R 20/04 Tuning or receiving; Circuits therefor
• CPC Class Codes: G04R 20/06 Decoding time data; Circuits therefor

Abstract

A method and apparatus for determining a reference time associated with a satellite positioning system. In turn, the reference time, in one embodiment, may be used to determine other navigational information. Such navigational information may include, for example, the location/position of a satellite positioning system (SPS) receiver. In one embodiment, a relative velocity between an SPS receiver and a set of one or more satellites is used to determine an offset between time as indicated by the SPS receiver and the reference time. According to another embodiment of the invention, an error statistic is used to determine the reference time. According to yet another embodiment of the invention, two records, each representing at least a portion of a satellite message, are compared to determine time. In one implementation, the SPS receiver is mobile and operates in conjunction with a basestation to determine time and/or other navigational information according to one or a combination of the methods described.

Claims

1. A method for determining time associated with a satellite positioning system, said method comprising:

storing a value to indicate a velocity of at least one satellite of the satellite positioning system; and

determining said time based on said value.

2. The method of claim 1, wherein the determining of said time comprises:

computing a first range value between an entity and said at least one satellite, said first range value associated with a first time error; and

determining an offset based on said value and said first range value, said offset indicating said first time error.

3. The method of claim 2, further comprising:

determining a position of said entity based on said first range value and said first time error.

4. The method of claim 3, wherein said entity comprises a mobile satellite positioning system (SPS) receiver.

5. The method of claim 3, wherein said determining of said position of said entity based on said first range value and said first time error is performed by a remote entity.

6. The method of claim 5, further comprising said remote entity providing navigational information to said entity, wherein said navigational information comprises information related to said position of said entity.

7. An apparatus for determining time associated with a satellite positioning system, said apparatus comprising:

a storage unit for storing a value to indicate a velocity of at least one satellite of the satellite positioning system; and

a processor coupled to the storage unit, said processor determining said time based on said value.

8. The apparatus of claim 7, wherein said processor determines said time by:

computing a first range value between an entity and said at least one satellite, said first range value associated with a first time error; and

determining an offset based on said value and said first range value, said offset indicating said first time error.

9. The apparatus of claim 8, wherein the processor determines a position of said entity based on said first range value and said first time error.

10. The apparatus of claim 9, wherein said entity comprises a mobile satellite positioning system (SPS) receiver and wherein said time is an SPS time.

11. The apparatus of claim 9, wherein said apparatus comprises said SPS receiver.

12. A machine readable medium containing executable instructions which when executed by a processing system cause the processing system to perform a method for determining time associated with a satellite positioning system, said method comprising:

storing a value to indicate a velocity of at least one satellite of the satellite positioning system; and

determining said time based on said value.

13. The machine readable medium of claim 12, wherein the determining said time comprises:

computing a first range value between an entity and said at least one satellite, said first range value associated with a first time error; and

determining an offset based on said value and said first range value, said offset indicating said first time error.

14. The machine readable medium of claim 13, the method further comprising determining a position of said entity based on said first range value and said first time error.

15. The machine readable medium of claim 14, wherein said entity comprises a mobile satellite positioning system (SPS) receiver and wherein said time is an SPS time.

16. The machine readable medium of claim 14, wherein determining said position of said entity based on said first range value and said first time error is performed by a remote entity.

17. The machine readable medium of claim 16, the method further comprising said remote entity providing navigational information to said entity, wherein said navigational information comprises information related to said position of said entity.