POSITION ESTIMATION FOR NAVIGATION DEVICES
First Claim
1. A method of providing position estimation with a navigation device, the method comprising:
- periodically recording magnetic field strength of an area substantially surrounding a navigation device as a user of the navigation device traverses a select pathway;
combining the recorded magnetic field strength with measurements from at least a dead reckoning portion of the navigation device to provide position estimates along the select pathway; and
correcting each of the position estimates from a starting position on the select pathway, each of the corrected position estimates having an error value below one or more previous position estimates and any intervening positions between each of the one or more previous position estimates and the starting position, the error value corresponding to an error threshold based on the previous position estimates.
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Accused Products
Abstract
A method of providing position estimation with a navigation device comprises periodically recording magnetic field strength of an area substantially surrounding a navigation device as a user of the navigation device traverses a select pathway. The method combines the recorded magnetic field strength with measurements from at least a dead reckoning portion of the navigation device to provide position estimates along the select pathway. The method further corrects each of the position estimates from a starting position on the select pathway, where each of the corrected position estimates have an error value below one or more previous position estimates and any intervening positions between each of the one or more previous position estimates and the starting position, with the error value corresponding to an error threshold based on the previous position estimates.
45 Citations
20 Claims
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1. A method of providing position estimation with a navigation device, the method comprising:
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periodically recording magnetic field strength of an area substantially surrounding a navigation device as a user of the navigation device traverses a select pathway; combining the recorded magnetic field strength with measurements from at least a dead reckoning portion of the navigation device to provide position estimates along the select pathway; and correcting each of the position estimates from a starting position on the select pathway, each of the corrected position estimates having an error value below one or more previous position estimates and any intervening positions between each of the one or more previous position estimates and the starting position, the error value corresponding to an error threshold based on the previous position estimates. - View Dependent Claims (2, 3, 4)
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5. A method of correlating position measurements of a navigation device, the method comprising:
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at a first time, continually recording position estimate measurements along a select pathway based on a measured magnetic field strength; on at least a second time of traversing the select pathway, automatically determining a track crossing based on a first position estimate within a navigation signature from at least one data channel, the at least one data channel corresponding to a navigation sensor of the navigation device; and once the track crossing is determined, aligning the track crossing of the first position estimate with one or more previous position estimates from one or more previous track crossings, the first position estimate adjusted to within a selectable error threshold based on at least one of the previous position estimates and any intervening positions between the at least one previous position estimate and the first position estimate. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A navigation device, comprising:
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a sensor module operable to provide position estimates based on magnetic field strength measurements and heading data; a processing unit configured to record the magnetic field strength measured by the sensor module of an area substantially surrounding a user of the navigation device, the processing unit further configured to measure a track crossing based on a comparison of a combined magnetic field strength and heading determination at a current position and one or more previous position estimates, and for each measured track crossing, align the current position with the one or more previous position estimates and adjust an accumulation of measurement error below an error threshold based on the one or more previous position estimates; and wherein the processing unit corrects any intervening positions and error estimates between the current position and the one or more previous position estimates. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification