SATELLITE SEARCH METHOD

• US 20070229352A1
• Filed: 12/01/2006
• Published: 10/04/2007
• Est. Priority Date: 03/28/2006
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Chen, Kun-tso, Huang, Kung-shuan, Ho, Jan-shin
• Granted Patent: US 7,671,796 B2
• Time in Patent Office: Days
• US Class Current: 342/357.670
• CPC Class Codes: G01S 19/28 Satellite selection

Abstract

A method for searching satellites is disclosed. In the method of the present invention, the satellites are selected to consist of a group, and searching is conducted in this group. The group size is predetermined for each stage so as to be the most appropriate for various searching conditions. The member number of the group (i.e. group size) and the members of the group are updated as the searching results are continually obtained. The updates are done according to scanning times of the group, satellite hit number, searching time for the group and satellite priorities and the like, for example. The group size can be reduced or expanded. By using the method, satellites required to fix a position can be rapidly found.

Claims

1. A method for searching a group of satellites in a satellite communication system, said method comprising steps of:

searching a satellite from the group; and

changing member number of the group depending on result of searching.

2. The method of claim 1, wherein the member number is changed whenever a satellite is searched to determine said satellite is hit or dismissed.

3. The method of claim 1, wherein the member number is changed whenever a predetermined number of satellites are searched to determine said satellites are hit or dismissed.

4. The method of claim 1, wherein the member number is changed when the group has been scanned over a predetermined number of times.

5. The method of claim 1, wherein the member number is reduced in the changing step.

6. The method of claim 1, wherein the member number is increased in the changing step.

7. The method of claim 1, wherein the member number is changed when the time of searching exceeds a threshold.

8. The method of claim 1, further comprising a step of updating members of the group.

9. The method of claim 8, wherein the members of the group are updated whenever the member number is changed.

10. The method of claim 9, wherein the members of the group are selected according to satellite priorities.

11. The method of claim 10, wherein the satellite priorities are determined based on conditional visibilities.

12. The method of claim 11, wherein the satellite priorities are determined further based on carrier-to-noise ratios of signals received from the satellites.

13. The method of claim 9, wherein the members are selected to be included in the group according to satellite priorities of all available satellites, and the satellite priorities are determined based on the searching result of said satellite.

14. The method of claim 8, wherein the members of the group are updated whenever a predetermined number of satellites are searched to determine said satellites are hit or dismissed.

15. The method of claim 14, wherein the members are selected according to the satellites priorities of all available satellites, and the satellite priorities are determined based on the searching results of said satellites.

16. The method of claim 14, wherein the members are selected to be included in the group according to satellite priorities of all available satellites, and the satellite priorities are determined based on each hit of said satellite.

17. The method of claim 14, wherein the members are selected to be included in the group according to satellite priorities of all available satellites, and the satellite priorities are determined based on each dismiss of said satellite.

18. The method of claim 14, wherein the members are selected according to the satellites priorities of all available satellites, and the satellite priorities are determined based on hits of said satellites.

19. The method of claim 14, wherein the members are selected according to the satellites priorities of all available satellites, and the satellite priorities are determined based on dismisses of said satellites.

20. The method of claim 1, wherein the communication system is a GNSS system.

21. The method of claim 1, wherein the communication system is a SBAS system.