Determining A Dilution of Precision Metric Using Two or Three GPS Satellites
First Claim
1. A method for determining a Dilution of Precision Metric (DOP) with less than four satellites in a hybrid positioning system, the method comprising:
- determining an initial position estimate of a device using a non-satellite positioning system;
obtaining satellite measurements from less than four satellites, wherein the measurements include each satellite'"'"'s position with respect to the initial position estimate;
constructing a geometry matrix corresponding to the measurements from the less than four satellites using each satellite'"'"'s position and the initial position estimate;
multiplying the geometry matrix by its transpose to construct an H matrix;
determining an inverse of the H matrix; and
determining the DOP based on a sum of the diagonal elements of the inverse H matrix.
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Abstract
The disclosed subject matter relates to a method for determining a Dilution of Precision Metric (DOP) with less than four satellites in a hybrid positioning system. In some embodiments, the method includes determining an initial position estimate of a device using a non-satellite positioning system, obtaining satellite measurements from less than four satellites, wherein the measurements include each satellite'"'"'s position with respect to the initial position estimate, constructing a geometry matrix corresponding to the measurements from the less than four satellites using each satellite'"'"'s position and the initial position estimate, multiplying the geometry matrix by its transpose to construct an H matrix, determining an inverse of the H matrix, and determining the DOP based on a sum of the diagonal elements of the inverse H matrix. In some embodiments, the non-satellite positioning system is a WLAN positioning system.
203 Citations
33 Claims
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1. A method for determining a Dilution of Precision Metric (DOP) with less than four satellites in a hybrid positioning system, the method comprising:
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determining an initial position estimate of a device using a non-satellite positioning system; obtaining satellite measurements from less than four satellites, wherein the measurements include each satellite'"'"'s position with respect to the initial position estimate; constructing a geometry matrix corresponding to the measurements from the less than four satellites using each satellite'"'"'s position and the initial position estimate; multiplying the geometry matrix by its transpose to construct an H matrix; determining an inverse of the H matrix; and determining the DOP based on a sum of the diagonal elements of the inverse H matrix. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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- 8. The method of 1 comprising not selecting the set of satellites to determine the position the mobile device and reporting the initial position estimate if DOP is large.
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11. A method for determining value of a Dilution of Precision Metric (DOP) with less than four satellites in a hybrid positioning system, the method comprising:
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determining an initial position estimate of a device using a non-satellite positioning system; obtaining satellite measurements from a set of three satellites, wherein the measurements include each satellite'"'"'s position with respect to the initial position estimate; rotating the set of satellites to form a rotated set of satellites having standard coordinates; determining a rotated geometry matrix using angles between the rotated set of satellites and the set of rotated axes; multiplying the geometry matrix by a transpose of the rotated geometry matrix to create an H matrix; and determining a DOP based on the diagonal elements of the inverse of the H matrix. - View Dependent Claims (12, 13, 14, 15)
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- 16. The method of 11 comprising refining the initial position estimate if the DOP is small.
- 18. The method of 11 comprising reporting the initial position estimate if the DOP is large.
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21. A method for determining a Dilution of Precision Metric (DOP) with less than four satellites in a hybrid positioning system, the method comprising:
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determining an initial position estimate of a device using a non-satellite positioning system; obtaining satellite measurements from less than four satellites, wherein the measurements include each satellite'"'"'s position with respect to the initial position estimate; and determining a DOP based on the initial position estimate and the satellite measurements from less than four satellites. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 30)
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29. The method of 27 comprising refining the initial position estimate if the DOP is small.
- 31. The method of 21 comprising reporting the initial position estimate if the DOP is large.
Specification