Always-on satellite positioning receiver

• US 20080218410A1
• Filed: 05/14/2008
• Published: 09/11/2008
• Est. Priority Date: 12/20/2006
• Status: Active Grant

• Current Assignee: U-Blox AG (u-blox Holding AG)
• Original Assignee: David P. Tester, Stephen P. Graham
• Inventors: Tester, David P., Graham, Stephen P.
• Granted Patent: US 7,564,403 B2
• Time in Patent Office: Days
• US Class Current: 342/357.12
• 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 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain

Abstract

A method to establish a position of a device receiving an input signal containing data from a plurality of satellites is disclosed. The method generally includes the steps of (A) calculating (i) an estimated position of the device and (ii) an estimated velocity vector of the device, (B) calculating a plurality of estimated locations of a plurality of pseudo-random code sequences in the input signal based on (i) the estimated position and (ii) the estimated velocity vector and (C) generating the position in an output signal based on the pseudo-random code sequences.

Claims

1. A method to establish a position of a device receiving an input signal containing data from a plurality of satellites, comprising the steps of:

(A) calculating (i) an estimated position of said device and (ii) an estimated velocity vector of said device;

(B) calculating a plurality of estimated locations of a plurality of pseudo-random code sequences in said input signal based on (i) said estimated position and (ii) said estimated velocity vector; and

(C) generating said position in an output signal based on said pseudo-random code sequences.

2. The method according to claim 1, wherein said estimated locations are calculated for fewer than all of said satellites with said data in said input signal.

3. The method according to claim 1, wherein said calculation of said estimated locations of said pseudo-random code sequences continues while said pseudo-random code sequences are unsuitable to track.

4. The method according to claim 1, further comprising the step of:

reporting said estimated position and said estimated velocity vector in said output signal while said pseudo-random code sequences are unsuitable to track.

5. The method according to claim 1, further comprising the step of:

calculating (i) said estimated position and (ii) said estimated velocity vector based on (a) a previous position of said device and (b) a previous velocity vector of said device.

6. The method according to claim 1, further comprising the step of:

reducing a power consumed by a receiver between updates of said position, wherein said receiver generates said input signal.

7. The method according to claim 1, further comprising the step of:

generating said position using a fast acquisition technique in response to at least one of (i) a power up of said device and (ii) a command to quickly establish said position from an unknown state.

8. The method according to claim 7, further comprising the step of:

reducing a power consumed by said fast acquisition technique after said position has been determined at least once.

9. The method according to claim 1, wherein said position is generated from at most four of said satellites.

10. The method according to claim 9, wherein said at most four satellites are a combination of said satellites with said data in said input signal that results in a best geometric dilution of precision metric.

11. A device comprising:

a tracking engine configured to (i) calculate a plurality of estimated locations of a plurality of pseudo-random code sequences in an input signal containing data from a plurality of satellites, said calculation of said estimated locations being based on (a) an estimated position of said device and (b) an estimated velocity vector of said device and (ii) generate an intermediate signal based on said pseudo-random code sequences; and

a position calculator co-located with said tracking engine and configured to generate (i) said estimated position, (ii) said estimated velocity vector and (iii) a position of said device in an output signal based on said intermediate signal.

12. The device according to claim 11, wherein said tracking engine is further configured to calculate said estimated locations for fewer than all of said satellites with said data in said input signal.

13. The device according to claim 11, wherein said tracking engine is further configured to calculate said estimated locations of said pseudo-random code sequences while said pseudo-random code sequences are unsuitable to track.

14. The device according to claim 11, wherein said position calculator is further configured to report said estimated position and said estimated velocity vector in said output signal while said pseudo-random code sequences are unsuitable to track.

15. The device according to claim 11, wherein said position calculator is further configured to calculate (i) said estimated position and (ii) said estimated velocity vector based on (a) a previous position of said device and (b) a previous velocity vector of said device.

16. The device according to claim 11, further comprising a power controller configured to reduce a power consumed by a receiver between updates in said position, wherein said receiver generates said input signal.

17. The device according to claim 11, further comprising a fast acquisition engine configured to establish said position in response to at least one of (i) a power up of said device and (ii) a command to quickly establish said position from an unknown state.

18. The device according to claim 17, further comprising a power controller configured to reduce a power consumption of said fast acquisition engine after establishing said position at least once.

19. The device according to claim 11, wherein said device comprises at least one of (i) a cell phone, (ii) a laptop computer, (iii) a palm computer, (iv) a personal digital assistant, (v) a heads-up display and (vi) a camera.

20. A device comprising:

means for (i) calculating a plurality of estimated locations of a plurality of pseudo-random code sequences in an input signal containing data from a plurality of satellites, said calculation of said estimated locations being based on (a) an estimated position of said device and (b) an estimated velocity vector of said device and (ii) generating an intermediate signal based on said pseudo-random code sequences; and

means for generating (i) said estimated position, (ii) said estimated velocity vector and (iii) a position of said device in an output signal based on said intermediate signal.