SYSTEMS AND METHODS FOR MAINTAINING CLOCK BIAS ACCURACY IN A HYBRID POSITIONING SYSTEM

• US 20100052983A1
• Filed: 06/05/2009
• Published: 03/04/2010
• Est. Priority Date: 06/06/2008
• Status: Abandoned Application

• Current Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Original Assignee: Skyhook Wireless Incorporated (Liberty Broadband Corp.)
• Inventors: Alizadeh-Shabdiz, Farshid
• Application Number:
  US12/479,722
• Publication Number:
  US 20100052983A1
• Time in Patent Office: Days
• US Class Current: 342/357.480
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• 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

Abstract

This disclosure describes systems and methods for maintaining clock bias accuracy in a hybrid positioning system. In some embodiments, the method to maintain the stability of an internal clock of an satellite positioning system receiver by using WLAN access points (APs) can include maintaining the internal clock accuracy of a satellite positioning system receiver by using one or more WLAN APs as a reference.

Claims

1. A method to maintain the stability of an internal clock of an satellite positioning system receiver by using WLAN access points (APs), the method comprising:

maintaining the internal clock accuracy of a satellite positioning system receiver by using one or more WLAN APs as a reference.

2. The method of claim 1, wherein maintaining the internal clock accuracy comprises measuring one or more time intervals of one or more signals transmitted by a WLAN AP and received by the satellite positioning system receiver.

3. The method of claim 1, wherein the WLAN AP maintains its internal clock accuracy by synchronizing with a satellite positioning system clock.

4. The method of claim 3, wherein the WLAN AP comprises a satellite positioning system receiver to synchronize with the satellite positioning system clock.

5. The method of claim 3, wherein the WLAN AP is connected to a central site to synchronize with the satellite positioning system clock.

6. The method of claim 1, wherein the WLAN AP maintain its internal clock accuracy by using an accurate internal oscillator receiver.

7. The method of claim 1 comprising:

receiving from the WLAN AP information about the accuracy of its internal oscillator or expected error of its timing; and

selecting timing measurements from different WLAN APs, to correct and maintain the satellite receiver'"'"'s internal clock bias.

8. The method of claim 7 comprising selecting WLAN APs with the accuracy of internal oscillator higher than the satellite receiver'"'"'s accuracy of internal oscillator.

9. The method of claim 1 wherein the WLAN AP is a municipal AP and the municipal AP is synchronized with a satellite positioning system clock.

10. The method of claim 1 wherein the satellite positioning system receiver comprises a WLAN receiver.

11. A satellite positioning receiver wherein the satellite positioning receiver maintains its internal clock bias by using one or more WLAN APs as a reference.

12. The receiver of claim 11, wherein the WLAN AP is a municipal AP.