Satellite positioning apparatus and method
First Claim
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 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.
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Accused Products
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.
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Citations
18 Claims
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1. A satellite positioning apparatus that performs positioning based on a signal received from a satellite, comprising:
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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 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.
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2. A satellite positioning apparatus that performs positioning based on a signal received from a satellite, comprising:
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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 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. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
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11. A satellite positioning method for performing positioning based on a signal received from a satellite, comprising:
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selecting a plurality of available satellites available for satellite positioning from satellites whose signals have been received;
selecting a predetermined number of designated satellites to be used for satellite positioning from the plurality of available satellites selected, the predetermined number of designated satellites being selected so that when the plurality of available satellites include a predetermined number of satellites selected as designated satellites for satellite positioning, the predetermined number of satellites selected as the designated satellites for the satellite positioning the previous time are designated as priority satellites for further satellite positioning; and
performing satellite positioning using the signals received from the designated satellites selected.
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12. A satellite positioning method for performing positioning based on a signal received from a satellite, comprising:
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selecting a plurality of available satellites available for satellite positioning from satellites whose signals have been received;
selecting a plurality of candidate satellites from the plurality of available satellites;
selecting a predetermined number of designated satellites to be used for satellite positioning from the plurality of candidate satellites, the predetermined number of designated satellites being selected so that when the plurality of candidate satellites include a predetermined number of satellites selected as designated satellites for satellite positioning, the predetermined number of satellites selected as the designated satellites for the satellite positioning are designated as priority satellites for further satellite positioning; and
performing satellite positioning using the signals received from the priority satellites.
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- 13. The method of claim 13, wherein selected available satellites have a variation level of signal receiving intensity that is smaller than a predetermined level for a predetermined period of time.
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15. The method of claim 15, wherein n is 4.
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16. The method of claim 16, wherein when the number of candidate satellites selected is three, the three satellites are selected as the designated satellites to be used for the satellite positioning, and
when the number of designated satellites selected is three, two-dimensional positioning is performed using the signals received from the three designated satellites.
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17. A position determining method for a navigation apparatus, for determining a current position, comprising:
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providing a navigation apparatus comprising a satellite positioning apparatus operable to perform positioning using satellite positioning and a self-contained-navigation positioning apparatus operable to perform positioning using self-contained navigation;
selecting a plurality of available satellites available for satellite positioning from satellites whose signals have been received;
selecting candidate satellites from the available satellites;
when the number of candidate satellites is n or greater, where n is an integer greater than three, selecting n satellites as designated satellites to be used for satellite positioning each time;
when the number of designated satellites selected is n, performing three-dimensional positioning using the signals received from the n designated satellites; and
at least when the number of candidate satellites selected is n or greater, determining the current position based on a position determined by the satellite positioning apparatus and a position determined by the self-contained-navigation positioning apparatus, and at least when the number of candidate satellites selected is smaller than three, determining the current position based on the position determined by the self-contained-navigation positioning apparatus.
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18. A position determining method for a navigation apparatus, for determining a current position, comprising:
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providing a navigation apparatus comprising a satellite positioning apparatus operable to perform positioning using satellite positioning and a self-contained-navigation positioning apparatus operable to perform positioning using self-contained navigation;
selecting a plurality of available satellites available for satellite positioning from satellites whose signals have been received;
selecting candidate satellites from the plurality of available satellites;
when the number of candidate satellites selected is four or greater, selecting four designated satellites to be used for satellite positioning so that when the candidate satellites include a predetermined number of satellites selected as designated satellites for satellite positioning, the predetermined number of satellites selected as the designated satellites for the satellite positioning are designated as priority satellites, and when the number of candidate satellites selected is three, designating the three satellites as priority satellites;
when the number of designated satellites selected is four, performing three-dimensional positioning using the signals received from the four designated satellites, and when the number of designated satellites selected is three, performing two-dimensional positioning using the signals received from the three designated satellites; and
when the number of candidate satellites selected is three or greater, determining the current position based on a position determined by the satellite positioning apparatus and a position determined by the self-contained-navigation positioning apparatus, and when the number of candidate satellites selected is smaller than three, determining the current position based on the position determined by the self-contained-navigation positioning apparatus.
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Specification