Triple multiplexing spread spectrum receiver

• US 7,295,633 B2
• Filed: 07/30/2004
• Issued: 11/13/2007
• Est. Priority Date: 03/15/1996
• Status: Expired due to Fees

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Kohli, Sanjai, Chen, Steven
• Primary Examiner(s): Bocure; Tesfaldet
• Application Number:
  US10/903,098
• Publication Number:
  US 20050002447A1
• Time in Patent Office: 1,201 Days
• Field of Search: 375/147, 375/130, 375/343, 375/316, 342/350, 34235701-35717, 342/357, 701/207, 701213-215
• US Class Current: 375/343
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G01C 22/00 Measuring distance traversed on the ground by vehicles, persons, animals or other moving solid bodies, e.g. using odometers, using pedometers
• CPC Class Codes: G01S 19/11 wherein the cooperating elements are pseudolites or satellite radio beacon positioning system signal repeaters
• CPC Class Codes: G01S 19/26 involving a sensor measurement for aiding acquisition or tracking
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G01S 19/48 by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
• CPC Class Codes: G01S 19/50 whereby the position solution is constrained to lie upon a particular curve or surface, e.g. for locomotives on railway tracks
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7085 using a code tracking loop, e.g. a delay-locked loop
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04B 2001/70706 using a code tracking loop, e.g. a delay locked loop
• CPC Class Codes: H04B 2201/70715 with application-specific features
• CPC Class Codes: H04B 7/216 Code division or spread-spectrum multiple access [CDMA, SSMA]

Abstract

A GPS car navigation system derives GPS position update information from motion of the car along the actual track. Turns along the track are detected when they actually occur and are compared with the predicted turns so that the time and position at the actual turn can be used to update the then current GPS derived position of the vehicle. Updating position information with actual turn data improves the accuracy of GPS navigation especially during single satellite navigation.

Claims

1. A method for navigating a vehicle using satellite C/A code signals, comprising:

navigating the vehicle using a first mode of navigation comprising a C/A code signal from a single satellite and cross-track hold data; and

navigating the vehicle using a second mode of navigation comprising updating satellite-derived data with data derived from detecting turns of the vehicle, wherein the first and second modes include correlating first sets of code sample segments against first sets of generated code delays.

2. A navigation device for determining a current position, comprising:

a database including map data of known positions in a geographic region;

a reference position detector that detects a change in direction of travel of the mobile device and, based on the change in direction, identifies one of the known positions as a reference position; and

a satellite-based positioning system that receives ranging signals from one or more satellites to determine a current position of the navigation device wherein, if the ranging signals of no more than a predetermined number of satellites are received, the satellite-based positioning system uses the reference position in addition to the ranging signals in determining the current position.

3. A navigation device as in claim 2, wherein the reference position detector compilses a dead-reckoning system.

4. A navigation device as in claim 2, wherein the reference position detector identifies the reference position based on a change in direction of travel of greater than a predetermined value.

5. A navigation device as in claim 4, wherein the predetermined value is 45 degrees.

6. A navigation device as in claim 2, wherein the satellite-based positioning system uses the reference position as a last known position of the navigation device.

7. A navigation device as in claim 2, wherein the satellite-based positioning system further takes into consideration a clock hold.

8. A navigation device as in claim 2, wherein the satellite-based positioning system further takes into consideration an altitude hold.

9. A method in claim 2, wherein the satellite-based positioning system further takes into consideration a clock hold.

10. A method as in claim 2, wherein the satellite-based positioning system further takes into consideration an altitude hold.

11. A method for determining a current position, comprising:

providing a database including map data of known positions in a geographic region;

detecting a reference position by detecting a change in direction of travel and, based on the change in direction, identifying one of the known positions as the reference position; and

in a satellite-based positioning system, supplementing ranging signals received from one or more satellites with the reference position to determine a current position, if the ranging signals of no more than a predetermined number of satellites are received.

12. A method as in claim 11, wherein the reference position is detected using a dead-reckoning system.

13. A method as in claim 11, wherein the reference position is identified based on a change in direction of travel of greater than a predetermined value.

14. A method as in claim 13, wherein the predetermined value is 45 degrees.

15. A method as in claim 11, wherein the satellite-based positioning system uses the reference position as a last known position of the navigation device.