Time of arrival based positioning system
First Claim
1. A method comprising:
- determining, at a first wireless device, an estimated distance between the first wireless device and each of a plurality of reference devices, wherein the estimated distance between the first wireless device and a respective reference device is based at least in part on a round trip transit time (RTT) associated with the respective reference device;
determining an initial position of the first wireless device based, at least in part, on a known position associated with at least one of the plurality of reference devices; and
and estimating a current position of the first wireless device and the first distance calibration value by executing a time of arrival (TOA) positioning operation based, at least in part, on the estimated distance between the first wireless device and each of the plurality of reference devices, the initial position of the first wireless device, the known position associated with at least one of the plurality of reference devices and an initial distance calibration value, wherein the executing the TOA positioning operation comprises;
determining a location error matrix, represented by a difference between an estimated location coordinate of the first wireless device and a corresponding initial location coordinate of the initial position of the first wireless device;
determining a distance error matrix, represented by a difference between the estimated distance between the first wireless device and one of the plurality of reference devices and a calculated distance between the first wireless device and the one of the plurality of reference devices; and
and determining a coefficient matrix as a product of the distance error matrix and an inverse of a transpose of the location error matrix.
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Abstract
A TOA positioning system can be implemented that employs a calculated initial location of a wireless network device. For each of a plurality of reference wireless network devices, a distance between the wireless network device and the reference wireless network device is determined based, at least in part, on a round trip transit time between the wireless network device and the reference wireless network device. An initial location of the wireless network device can be calculated based, at least in part, on a location of each of the plurality of reference wireless network devices. A location of the wireless network device can be estimated based, at least in part, on the calculated initial location, the distance to each of the reference wireless network devices, and an initial distance calibration constant.
60 Citations
27 Claims
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1. A method comprising:
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determining, at a first wireless device, an estimated distance between the first wireless device and each of a plurality of reference devices, wherein the estimated distance between the first wireless device and a respective reference device is based at least in part on a round trip transit time (RTT) associated with the respective reference device; determining an initial position of the first wireless device based, at least in part, on a known position associated with at least one of the plurality of reference devices; and and estimating a current position of the first wireless device and the first distance calibration value by executing a time of arrival (TOA) positioning operation based, at least in part, on the estimated distance between the first wireless device and each of the plurality of reference devices, the initial position of the first wireless device, the known position associated with at least one of the plurality of reference devices and an initial distance calibration value, wherein the executing the TOA positioning operation comprises; determining a location error matrix, represented by a difference between an estimated location coordinate of the first wireless device and a corresponding initial location coordinate of the initial position of the first wireless device; determining a distance error matrix, represented by a difference between the estimated distance between the first wireless device and one of the plurality of reference devices and a calculated distance between the first wireless device and the one of the plurality of reference devices; and and determining a coefficient matrix as a product of the distance error matrix and an inverse of a transpose of the location error matrix. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A first wireless device comprising:
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a network interface; and a position calculation unit coupled with the network interface, the position calculation unit configured to; determine, at the first wireless device, an estimated distance between the first wireless device and each of a plurality of reference devices, wherein the estimated distance between the first wireless device and a respective reference device is based at least in part on a round trip tansit time (RTT) associated with the respective reference device; determine an initial position of the first wireless device based, at least in part, on a known position associated with at least one of the plurality of reference devices; and estimate a current position of the first wireless device and the first distance calibration value by executing a time of arrival (TOA) positioning operation based, at least in part, on the estimated distance between the first wireless device and each of the plurality of reference devices, the initial position of the first wireless device, the known position associated with at least one of the plurality of reference devices and an initial distance calibration value, wherein the executing the TOA positioning operation comprises the position calculation unit configured to; determine a location error matrix, represented by a difference between an estimated location coordinate of the first wireless device and a corresponding initial location coordinate of the initial position of the first wireless device; determine a distance error matrix, represented by a difference between the estimated distance between the first wireless device and one of the plurality of reference devices and a calculated distance between the first wireless device and the one of the plurality of reference devices; and determine a coefficient matrix as a product of the distance error matrix and an inverse of a transpose of the location error matrix. - View Dependent Claims (22, 23, 24, 25)
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26. A non-transitory machine-readable storage media having instructions stored therein, which when executed by a processor of a first wireless device causes the first wireless device to perform operations comprising:
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determining, at the first wireless device, an estimated distance between the first wireless device and each of a plurality of reference devices, wherein the estimated distance between the first wireless device and a respective reference device is based at least in part on a round trip transit time (RTT) associated with the respective reference device; determining an initial position of the first wireless device based, at least in part, on a known position associated with at least one of the plurality of reference devices; and estimating a current position of the first wireless device and the first distance calibration value by executing a time of arrival (TOA) positioning operation based, at least in part, on the estimated distance between the first wireless device and each of the plurality of reference devices, the initial position of the first wireless device, the known position associated with at least one of the plurality of reference devices, and an initial distance calibration value, wherein the executing the TOA positioning operation comprises; determining a location error matrix, represented by a difference between an estimated location coordinate of the first wireless device and a corresponding initial location coordinate of the initial position of the first wireless device; determining a distance error matrix, represented by a difference between the estimated distance between the first wireless device and one of the plurality of reference devices and a calculated distance between the first wireless device and the one of the plurality of reference devices; and determining a coefficient matrix as a product of the distance error matrix and an inverse of a transpose of the location error matrix. - View Dependent Claims (27)
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Specification