System and method for localization over a wireless network
First Claim
1. A method for identifying the location of a device in a building, device in a defined area, comprising the steps of:
- creating a signal map, wherein the signal map is created by recording a set of wireless signal intensities for a set of regions or offices in the building, and wherein each set of signal intensities is fitted to a Gaussian distribution;
receiving at the device a signal; and
comparing the signal to the set of Gaussian distributions to identify the location of the device in the building.
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Abstract
A system for locating a wireless device involves the use of the measured signal strength of various base stations in the building or outdoor area under analysis. A topological map of the building or outdoor area under analysis is created. The map is divided into cells, and signal intensities are collected in each cell. For each cell, the signal from a particular base station is fit to a statistical distribution, such as a Gaussian distribution, and the parameters of the statistical distribution are estimated. After a device obtains a set of signal strength measurements, a probabilistic technique is employed to estimate the probability of the existence of the measurements in each of the cells of the building or area under analysis. The estimated location is the cell with the highest probability. A mobile user is tracked with the use of a Markov chain and the system can be calibrated to account for equipment and environmental variations.
76 Citations
20 Claims
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1. A method for identifying the location of a device in a building, device in a defined area, comprising the steps of:
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creating a signal map, wherein the signal map is created by recording a set of wireless signal intensities for a set of regions or offices in the building, and wherein each set of signal intensities is fitted to a Gaussian distribution;
receiving at the device a signal; and
comparing the signal to the set of Gaussian distributions to identify the location of the device in the building. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for identifying the location of a wireless device in a defined area, comprising the steps of:
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dividing the defined area into a number of cells;
within each cell, measuring the strength of a signal received from each of a number of base stations;
calculating a statistical representation of the measured signal strength for each cell with respect to each base station within range of the cell;
receiving at the wireless device a signal from a number of base stations and generating a signal strength reading; and
identifying the cell of the wireless device through a comparison of the signal strength reading at the device with the calculated statistical representations of the measured signal strengths for each cell. - View Dependent Claims (10, 11, 12, 13, 15, 16)
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14. The method for identifying the location of a wireless device in a defined area of claim, wherein the probabilistic determination involves a Bayesian analysis.
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17. A method for identifying the location of a wireless device in a defined area having a number of defined cells, wherein each cell is associated with a reference signal strength, comprising the steps of:
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receiving at the wireless device a signal from a number of base stations and generating a signal strength reading;
comparing the signal strength reading to the reference signal and adjusting the signal strength reading on the basis of the comparison;
identifying the cell of the wireless device through a comparison of the adjusted signal strength reading with a set of calculated statistical representations of the reference signal strengths for each cell. - View Dependent Claims (18, 19, 20)
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Specification