Method and apparatus for automatic and autonomous assignment of PRN codes to a multiplicity of pseudolites

• US 6,198,432 B1
• Filed: 09/29/1999
• Issued: 03/06/2001
• Est. Priority Date: 09/29/1999
• Status: Expired due to Term

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Janky, James M.
• Primary Examiner(s): Issing, Gregory C
• Application Number:
  US09/409,023
• Time in Patent Office: 524 Days
• Field of Search: 342/357.03, 342/357.14, 342/386, 342/357.06, 342/357.09, 342/357.15
• US Class Current: 342/357.31
• CPC Class Codes: G01S 19/11 wherein the cooperating elements are pseudolites or satellite radio beacon positioning system signal repeaters

Abstract

A pseudolite for transmitting a global positioning system (GPS) signal having identification information for a GPS satellite that is currently out-of-view. The pseudolite mimics a global positioning system (GPS) signal by using a C/A pseudorandom (PRN) identification code for a GPS satellite that is allocated in the GPS system but is unreceivable in the local vicinity and location-determination information including ephemeris data corresponding to the geographical location of the pseudolite. In order to ensure that two of the GPS pseudolites in the same vicinity do not use the identification PRN code from the same out-of-view GPS satellite, the pseudolite listens first before transmitting to detect the identifications in the received GPS signals.

Claims

1. A pseudolite for a positioning system (PS), said positioning system having several orbiting PS satellites transmitting respective PS signals, each one of said PS signals having an identification for a one of said PS satellites transmitting said one of said PS signals and location-determination information corresponding to a location-in-space for said one of said PS satellites transmitting said one of said PS signals, the pseudolite comprising:

an availability calculator for determining unreceivable ones of said PS satellites;

an identification selector coupled to the availability calculator for selecting a particular one of said identifications corresponding to a particular one of said unreceivable PS satellites; and

a transmitter coupled to the identification selector for transmitting a pseudo PS signal having said particular identification and location-determination information corresponding to a geographical location of the pseudolite.

2. The pseudolite of claim 1, wherein:

the availability calculator includes a visibility calculator for determining out-of-view ones of said PS satellites and designating said out-of-view PS satellites as said unreceivable PS satellites.

3. The pseudolite of claim 2, wherein:

said visibility calculator is for determining said out-of-view PS satellites based upon PS satellite orbital parameter information and time.

4. The pseudolite of claim 2, wherein:

said visibility calculator is for determining said out-of-view PS satellites based upon location information and height of a local obstruction.

5. The pseudolite of claim 1, wherein:

the availability calculator includes an operational identifier for determining non-operational ones of said PS satellites and designating said non-operational PS satellites as said unreceivable PS satellites.

6. The pseudolite of claim 1, wherein:

said PS satellites include GPS satellites for transmitting GPS signals as said PS signals having said identification in a form of a distinguishable pseudorandom spreading code.

7. The pseudolite of claim 1, wherein:

said PS satellites include global orbiting navigation system (GLONASS) satellites for transmitting GLONASS signals as said PS signals having said identification in a form of a distinguishable carrier frequency.

8. The pseudolite of claim 1, further comprising:

a pseudolite PS receiver for receiving signal energy for received ones of said PS signals having corresponding received ones of said identifications; and

a pseudolite detector for preventing the identification selector from selecting any one of said received identifications as said particular identification.

9. The pseudolite of claim 1, wherein:

said pseudo PS signal is for reception by a PS navigation receiver for determining at least one of (i) location and (ii) time.

10. A method in a pseudolite for a positioning system (PS), said positioning system having several orbiting PS satellites transmitting respective PS signals, each one of said PS signals having an identification for a one of said s PS satellites transmitting said one of said PS signals and location-determination information corresponding to a location-in-space for said one of said PS satellites transmitting said one of said PS signals, the method comprising steps of:

determining unreceivable ones of said PS satellites;

selecting a particular one of said identifications corresponding to a particular one of said unreceivable PS satellites; and

transmitting a pseudo PS signal having said particular identification and location-determination information corresponding to a geographical location of the pseudolite.

11. The method of claim 10, wherein:

the step of determining said unreceivable PS satellites includes steps of;

determining out-of-view ones of said PS satellites; and

designating said out-of-view PS satellites as said unreceivable PS satellites.

12. The method of claim 11, wherein:

the step of determining said out-of-view PS satellites includes determining said out-of-view PS satellites based upon PS satellite orbital parameter information and time.

13. The method of claim 11, wherein:

the step of determining said out-of-view PS satellites includes determining said out-of-view PS satellites based upon location and height of a local obstruction.

14. The method of claim 10, wherein:

the step of determining said unreceivable PS satellites includes steps of;

determining non-operational ones of said PS satellites; and

designating said non-operational PS satellites as said unreceivable PS satellites.

15. The method of claim 10, wherein:

said PS satellites include GPS satellites for transmitting GPS signals as said PS signals having said identification in a form of a distinguishable pseudorandom spreading code.

16. The method of claim 10, wherein:

said PS satellites include global orbiting navigation system (GLONASS) satellites for transmitting GLONASS signals as said PS signals having said identification in a form of a distinguishable carrier frequency.

17. The method of claim 10, further comprising steps of:

receiving signal energy for received ones of said PS signals having corresponding received ones of said identifications; and

the step of selecting particular identification includes selecting said particular identification not corresponding to any one of said received identifications.

18. The method of claim 10, wherein:

said pseudo PS signal is for reception by a PS navigation receiver for determining at least one of (i) location and (ii) time.