METHOD FOR CALCULATING CURRENT POSITION COORDINATE
First Claim
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1. A method for calculating current position coordinate, applicable to a global positioning system (GPS) receiver, comprising:
- Step 1;
searching for at least three satellites;
Step 2;
obtaining an ephemeris data of each of the at least three satellites at a first time point;
Step 3;
calculating a position coordinate of the GPS receiver at the first time point by utilizing the ephemeris data of each satellite;
Step 4;
calculating a position coordinate of each satellite at a second time point by utilizing the ephemeris data of each satellite, wherein the second time point is later than the first time point;
Step 5;
calculating a relative distance between the position coordinate of the GPS receiver at the first time point and the position coordinate of each satellite at the second time point;
Step 6;
evaluating a maximum moving distance of the GPS receiver from the first time point to the second time point;
Step 7;
calculating at least three distance ranges corresponding to the at least three satellites according to the respective relative distances and the maximum moving distance;
Step 8;
calculating a code delay of each satellite in the corresponding distance range to obtain the code delay of each satellite at the second time point; and
Step 9;
calculating the position coordinate of the GPS receiver at the second time point by utilizing the code delay at the second time point.
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Abstract
A method for calculating current position coordinate is applied to a global positioning system (GPS) receiver. When positioning at a current time point, the GPS receiver directly calculates a code delay and a carrier frequency of each satellite and position coordinate of the GPS receiver at a current positioning time point by utilizing an ephemeris data of each satellite and position coordinate of the GPS receiver at a last positioning time point, thereby greatly lowering an operation amount, so as to reduce the power consumption.
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Citations
11 Claims
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1. A method for calculating current position coordinate, applicable to a global positioning system (GPS) receiver, comprising:
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Step 1;
searching for at least three satellites;Step 2;
obtaining an ephemeris data of each of the at least three satellites at a first time point;Step 3;
calculating a position coordinate of the GPS receiver at the first time point by utilizing the ephemeris data of each satellite;Step 4;
calculating a position coordinate of each satellite at a second time point by utilizing the ephemeris data of each satellite, wherein the second time point is later than the first time point;Step 5;
calculating a relative distance between the position coordinate of the GPS receiver at the first time point and the position coordinate of each satellite at the second time point;Step 6;
evaluating a maximum moving distance of the GPS receiver from the first time point to the second time point;Step 7;
calculating at least three distance ranges corresponding to the at least three satellites according to the respective relative distances and the maximum moving distance;Step 8;
calculating a code delay of each satellite in the corresponding distance range to obtain the code delay of each satellite at the second time point; andStep 9;
calculating the position coordinate of the GPS receiver at the second time point by utilizing the code delay at the second time point. - View Dependent Claims (2, 3, 4, 5)
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6. A method for calculating current position coordinate, applicable to a global positioning system (GPS) receiver, comprising:
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searching for at least three satellites, so as to obtain ephemeris data of the at least three satellites; and calculating position coordinate of the GPS receiver at a current time point by utilizing the ephemeris data of each satellite and the position coordinate of the GPS receiver at a last time point, comprising; calculating position coordinate of each satellite at the current time point by utilizing the ephemeris data of each satellite; calculating a relative distance between the position coordinate of the GPS receiver at the last time point and the position coordinate of each satellite at the current time point; evaluating a maximum moving distance of the GPS receiver from the last time point to the current time point; calculating at least three distance ranges corresponding to the at least three satellite according to the respective relative distances and the maximum moving distance; calculating a code delay of each satellite in the corresponding distance range to obtain the code delay of each satellite at the current time point; and calculating the position coordinate of the GPS receiver at the current time point by utilizing the code delay of the current time point. - View Dependent Claims (7, 8, 9, 10, 11)
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Specification