Calibration of WLAN access points for location services
First Claim
1. A wireless communication device, comprising:
- a clock configured to track a current time;
a memory that stores a calibration location;
a processor configured to, in response to an input, generate a calibration signal that includes the calibration location and the current time;
an input-output (I/O) module configured to generate a message to cause the wireless communication device to be moved to the calibration location, and to receive the input to generate the calibration signal; and
a radio configured to transmit the calibration signal to a wireless communication environment,wherein the calibration location is a location of the wireless communication device at a time of transmitting the calibration signal,wherein the memory stores a plurality of calibration locations, andwherein the processor is further configured to, after transmitting the calibration signal, cause the I/O module to generate a message to cause the wireless communication device to be moved to a second calibration location of the plurality of calibration locations.
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Accused Products
Abstract
Wireless access points within a GPS-Unavailable environment can provide location services to user equipment devices within the environment provided that the access points are aware of their precise locations. In order to calibrate the locations of the wireless access points, a user equipment is moved to specific locations within the environment. At each of those locations, the user equipment transmits calibration signals that include the transmission location as well as a timestamp of the transmission time. Upon receipt by the access points, these signals are timestamped with a reception timestamp by a clock that is synchronized with the clock of the user equipment. After accumulating sufficient calibration information from a sufficient number of calibration locations, the access points can accurately determine their locations using trigonometric and other functions.
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Citations
15 Claims
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1. A wireless communication device, comprising:
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a clock configured to track a current time; a memory that stores a calibration location; a processor configured to, in response to an input, generate a calibration signal that includes the calibration location and the current time; an input-output (I/O) module configured to generate a message to cause the wireless communication device to be moved to the calibration location, and to receive the input to generate the calibration signal; and a radio configured to transmit the calibration signal to a wireless communication environment, wherein the calibration location is a location of the wireless communication device at a time of transmitting the calibration signal, wherein the memory stores a plurality of calibration locations, and wherein the processor is further configured to, after transmitting the calibration signal, cause the I/O module to generate a message to cause the wireless communication device to be moved to a second calibration location of the plurality of calibration locations. - View Dependent Claims (2, 3, 4, 5, 15)
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6. A wireless communication device, comprising:
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a memory; a radio configured to receive a calibration signal from an external wireless communication device, the calibration signal including calibration information that includes at least a transmission location and a transmission time associated with transmission of the calibration signal; a clock configured to track a current time; and a processor configured to acquire a timestamp from the clock upon receipt of the calibration signal corresponding to a time of receipt of the calibration signal, extract the calibration information from the calibration signal, and store the extracted calibration information and the timestamp together in the memory, wherein the processor is further configured to calculate a location of the wireless communication device based on the extracted calibration information and the corresponding timestamp, wherein the extracted calibration information and the corresponding timestamp constitute a calibration dataset, wherein the processor is further configured to determine whether a predetermined number of calibration datasets have been accumulated in the memory, and wherein the processor is further configured to calculate the location only in response to determining that the predetermined number of calibration datasets have been accumulated in the memory. - View Dependent Claims (7, 8)
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9. A method of calibrating a location of an access point, the method comprising:
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receiving a plurality of calibration signals from a plurality of corresponding calibration locations, each calibration signal including a transmission timestamp and a location identifier corresponding to the calibration location of the calibration signal, the calibration location being a location from which the calibration signal is transmitted; timestamping each of the received plurality of calibration signals upon receipt with a reception timestamp; determining that a number of the received plurality of calibration signals exceeds a predetermined threshold; and calculating the location of the access point based on the received plurality of calibration signals and the corresponding timestamps. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification