Satellite positioning apparatus and method

• US 7,295,155 B2
• Filed: 03/04/2005
• Issued: 11/13/2007
• Est. Priority Date: 03/05/2004
• Status: Active Grant

• Current Assignee: Alpine Electronics Incorporated (Alps Alpine Co., Ltd.)
• Original Assignee: Alpine Electronics Incorporated (Alps Alpine Co., Ltd.)
• Inventors: Wakamatsu, Kotaro
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): LY, HIEN QUANG
• Application Number:
  US11/073,024
• Publication Number:
  US 20050195107A1
• Time in Patent Office: 984 Days
• Field of Search: 34235701-35717, 342/464, 701/213, 701/214, 3409951-99528, 340/988
• US Class Current: 342/357.67
• CPC Class Codes: G01S 19/28 Satellite selection
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled

Abstract

Available-satellite data indicating satellites available for satellite positioning is obtained from a GPS receiver, and satellites continuously available for satellite positioning in the current instance and the previous n times are extracted as candidate satellites referring to available-satellite record data. Four of the candidate satellites are selected so that the satellites used for satellite positioning the previous time are selected with priority as the satellites to be used for satellite positioning in the current instance, and the selected satellites are set in designated-satellite data. The GPS receiver performs three-dimensional positioning using the four satellites designated by the designated-satellite data. If the number of extracted candidate satellites is three, these three extracted candidate satellites are selected as the designated satellites and are set in the designated-satellite data. The GPS receiver performs two-dimensional positioning using these three designated satellites. If the number of extracted candidate satellites is smaller than three, satellite positioning is not performed.

Claims

1. A satellite positioning apparatus that performs positioning based on a signal received from a satellite, comprising:

an available-satellite selecting unit operable to select a plurality of available satellites available for satellite positioning from satellites whose signals have been received;

a designated-satellite selecting unit operable to select a predetermined number of designated satellites to be used for satellite positioning from the plurality of available satellites selected by the available-satellite selecting unit, the predetermined number of designated satellites being selected so that when the plurality of available satellites include a predetermined number of satellites that were previously selected as designated satellites for satellite positioning, the predetermined number of satellites selected as the designated satellites for the satellite positioning at the previous time are designated as priority satellites for further satellite positioning; and

a satellite positioning unit operable to perform satellite positioning using the signals received from the priority satellites.

2. A satellite positioning apparatus that performs positioning based on a signal received from a satellite, comprising:

an available-satellite selecting unit operable to select a plurality of available satellites available for satellite positioning from satellites whose signals have been received;

a candidate-satellite selecting unit operable to select a plurality of candidate satellites from the available satellites selected by the available-satellite selecting unit;

a designated-satellite selecting unit operable to select a predetermined number of designated satellites to be used for satellite positioning from the plurality of candidate satellites selected by the candidate-satellite selecting unit, the predetermined number of designated satellites being selected so that when the plurality of candidate satellites include a predetermined number of satellites that were previously selected as designated satellites for satellite positioning, the predetermined number of satellites selected as the designated satellites for the satellite positioning at the previous time are designated as priority satellites for further satellite positioning; and

a satellite positioning unit operable to perform satellite positioning using the signals received from the priority satellites.

3. The apparatus of claim 2, wherein the candidate-satellite selecting unit selects satellites that have a variation level of signal receiving intensity that is smaller than a predetermined level for a predetermined period of time.

4. The apparatus of claim 2, wherein the available-satellite selecting unit selects satellites having at least an elevation angle greater than a predetermined value.

5. The apparatus of claim 2, wherein the available-satellite selecting unit selects satellites having at least a signal receiving intensity level higher than a predetermined level.

6. The apparatus of claim 2, wherein the available-satellite selecting unit selects satellites providing the best or better dilution of precision than a predetermined level.

7. The apparatus of claim 2, wherein when the number of candidate satellites selected by the candidate-satellite selecting unit is n or greater, where n is an integer greater than three, the designated-satellite selecting unit selects n satellites as the designated satellites to be used for the satellite positioning each time, and

when the number of designated satellites selected by the designated-satellite selecting unit is n, the satellite positioning unit performs three-dimensional positioning using the signals received from the n designated satellites.

8. The apparatus of claim 7 further comprising:

a self-contained-navigation positioning apparatus operable to perform positioning using self-contained navigation; and

a current-position determining unit operable to determine a current position based on a position determined by the satellite positioning apparatus and a position determined by the self-contained-navigation positioning apparatus,

wherein the current-position determining unit determines the current position based on the position determined by the self-contained-navigation positioning apparatus when the number of candidate satellites selected by the candidate-satellite selecting unit is smaller than three.

9. The apparatus of claim 7, wherein n is 4.

10. The apparatus of claim 9, wherein when the number of candidate satellites selected by the candidate-satellite selecting unit is three, the designated-satellite selecting unit selects the three satellites as the designated satellites to be used for the satellite positioning each time, and

when the number of designated satellites selected by the designated-satellite selecting unit is three, the satellite positioning performs two-dimensional positioning using the signals received from the three designated satellites.