Method and system for determining a location using a plurality of selected initial location estimates
First Claim
1. A method of determining a location of a plurality of units, each unit being communicatively coupled to at least some of the other plurality of units, wherein at least some of the plurality of units are in communication range with one or more reference units, whose locations are at least one of determined and known, said method comprising:
- measuring range information between each of the units and any reference units within communication range of one another;
establishing a possible location area for each of the units including a plurality of possible initial location estimates;
selecting an initial location estimate for each of the units, whose location is not known, from an area corresponding to the possible location area;
estimating a location for each of the units, which minimizes an error value, based on the difference between the measured range values and a range calculated from the estimated location values;
repeating, at least once, the selection of initial location estimates using a different set of initial location estimates for each of the units from the plurality of possible initial location estimates and the estimation of a location for each of the units, which minimizes an error value; and
selecting the set of location estimates from the repeated estimations having the smallest minimized error value.
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Abstract
A method and system is provided for determining a location for each of a plurality of units, which is selected from one of multiple sets of locations, which are each estimated based upon different initial location estimates. The selected set of locations includes the set which has the minimum error value, where the error value is based on the aggregate of the differences between the range determined from the estimated locations and the measured range. By using different sets of initial location estimates, there is a greater chance that at least one of the sets of initial location estimates will avoid any local minimums and produce a more accurate estimate of unit locations.
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Citations
24 Claims
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1. A method of determining a location of a plurality of units, each unit being communicatively coupled to at least some of the other plurality of units, wherein at least some of the plurality of units are in communication range with one or more reference units, whose locations are at least one of determined and known, said method comprising:
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measuring range information between each of the units and any reference units within communication range of one another;
establishing a possible location area for each of the units including a plurality of possible initial location estimates;
selecting an initial location estimate for each of the units, whose location is not known, from an area corresponding to the possible location area;
estimating a location for each of the units, which minimizes an error value, based on the difference between the measured range values and a range calculated from the estimated location values;
repeating, at least once, the selection of initial location estimates using a different set of initial location estimates for each of the units from the plurality of possible initial location estimates and the estimation of a location for each of the units, which minimizes an error value; and
selecting the set of location estimates from the repeated estimations having the smallest minimized error value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A system for determining the location for each of a plurality of units in a multi-hop network, each unit being communicatively coupled to at least some of the other plurality of units, wherein at least some of the plurality of units are in communication range with one or more reference units, whose location is at least one of determined or known, said system comprising:
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a transceiver for receiving connectivity and range information for the plurality of units and the reference units in communication range with one another; and
a processor coupled to the transceiver, the processor including a storage area for maintaining the connectivity, communication range information, and multiple sets of location estimates and corresponding minimized error values, a calculation module adapted for determining possible location areas for each of the units and estimating a location for each of the units, which minimizes an error value, based upon each set of initial location estimates, and one or more selection modules for sequentially selecting multiple different sets of initial location estimates corresponding to the possible location areas for each of the units, and selecting the set of estimated locations, which is associated with the smallest minimized error value. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24)
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Specification