Location estimation method
First Claim
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1. A location estimation method for locating a mobile station (MS) by a plurality of base stations (BS), comprising:
- analyzing a geometric distribution of the BSs to provide a list of conditional equations;
allocating virtual BSs having virtual distances to the MS to provide constraint equations; and
estimating the MS location based on the conditional equations and the constraint equations;
wherein analysis of the geometric distribution comprises;
transmitting coordinates of each BS to the MS;
estimating time-of arrival (TOA) of signals transmitted to or from the BSs to obtain measured distances correspondingly;
measuring noise level of each transmission to calculate standard deviations of the measured distances;
generating the conditional equations based on the measured distances and the standard deviations;
calculating an initial estimate of the MS location based on the standard deviations and coordinates of the BSs;
determining the virtual distances based on the initial estimate of the MS location, the coordinates of the BSs and a plurality of virtual coefficients each corresponding to a BS; and
rendering a GDOP contour based on the analysis of the geometric distribution, statistically presenting measurement error distribution of the BSs;
wherein allocation of the virtual BS comprises;
observing peak values distributed in the GDOP contour; and
allocating the virtual BSs to the positions where at least one peak value is causally smoothed away.
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Abstract
A location estimation method is provided. The method locates coordinates of a mobile station (MS) by referencing a plurality of base stations (BS). A geometric distribution of the BS is analyzed to provide a list of conditional equations. A virtual BS is allocated, having a virtual distance to the MS to provide a constraint equation. The MS location is derived from the conditional equations and the constraint equation.
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Citations
6 Claims
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1. A location estimation method for locating a mobile station (MS) by a plurality of base stations (BS), comprising:
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analyzing a geometric distribution of the BSs to provide a list of conditional equations; allocating virtual BSs having virtual distances to the MS to provide constraint equations; and estimating the MS location based on the conditional equations and the constraint equations; wherein analysis of the geometric distribution comprises; transmitting coordinates of each BS to the MS; estimating time-of arrival (TOA) of signals transmitted to or from the BSs to obtain measured distances correspondingly; measuring noise level of each transmission to calculate standard deviations of the measured distances; generating the conditional equations based on the measured distances and the standard deviations; calculating an initial estimate of the MS location based on the standard deviations and coordinates of the BSs; determining the virtual distances based on the initial estimate of the MS location, the coordinates of the BSs and a plurality of virtual coefficients each corresponding to a BS; and rendering a GDOP contour based on the analysis of the geometric distribution, statistically presenting measurement error distribution of the BSs; wherein allocation of the virtual BS comprises; observing peak values distributed in the GDOP contour; and allocating the virtual BSs to the positions where at least one peak value is causally smoothed away. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification