Method and apparatus for determining location of a communication device
First Claim
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1. A method for determining a distance of a communication device from a reference device, the method comprising:
- the reference device determining a calibrated time delay representative of a steady-state internal processing delay of the communication device by conducting a training process while the communication device is at a known distance from the reference device, the training process comprising transmitting a plurality of location request training signals to the communication device and receiving a corresponding plurality of location response training signals;
subsequent to conducting the training process, the reference device measuring a second time delay, while the communication device is at a second unknown distance from the reference device, corresponding to a time between the reference device transmitting a location request signal and receiving a location response signal;
the reference device calculatingthe second unknown distance using the second time delay and the calibrated time delay.
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Abstract
A reference device determines its distance from a communication device by first using a training process to determine a calibrated time delay for the communication device when the communication device is at a known distance from the reference device. The calibrated time delay is a steady state internal processing delay for the communication device. Subsequently, when the reference device is at an unknown distance from the communication device, the reference device determines the unknown distance using the previously determined calibrated time delay along with a measured signal travel time at the unknown distance.
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Citations
20 Claims
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1. A method for determining a distance of a communication device from a reference device, the method comprising:
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the reference device determining a calibrated time delay representative of a steady-state internal processing delay of the communication device by conducting a training process while the communication device is at a known distance from the reference device, the training process comprising transmitting a plurality of location request training signals to the communication device and receiving a corresponding plurality of location response training signals; subsequent to conducting the training process, the reference device measuring a second time delay, while the communication device is at a second unknown distance from the reference device, corresponding to a time between the reference device transmitting a location request signal and receiving a location response signal; the reference device calculating the second unknown distance using the second time delay and the calibrated time delay. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for enabling a distance determination of a communication device from a reference device, the method comprising:
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at the communication device, during a training process conducted while the communication device is at a known distance from the reference device; sending at least one pulse of an initial inbound location pulse sequence in response to an initial request from the reference device; receiving an intermediate time delay from the reference device representative of a first intermediate internal processing delay of the communication device in processing the first request; configuring internal processes based on the intermediate time delay to enable the reference device to calculate a calibrated time delay that comprises a steady state internal processing delay for the communication device, and storing the configuration; receiving and storing the calibrated time delay; at the communication device, while the communication device is at an unknown second distance from the reference device; receiving a location request signal from the reference device; further configuring internal processes in accordance with the stored configuration; transmitting location response signal to the reference device; and retrieving the calibrated time delay from storage and sending the calibrated time delay to the reference device. - View Dependent Claims (15, 16, 17, 18)
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19. A reference device for determining an unknown distance of a communication device from the reference device, the reference device comprising:
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a first radio interface configured to transmit and receive, on a narrowband channel, control information related to an inbound location pulse sequence; a second radio interface configured to receive, on a wideband channel, the inbound location pulse sequence from the communication device; a processor; and instructions, contained in data storage, that are executable by the processor for causing the reference device to carry out steps including; while the communication device is at a known distance from the reference device; sending, via the first radio interface, a request to the communication device to initiate the inbound location pulse sequence; receiving, via the second radio interface, at least one pulse of the inbound location pulse sequence from the communication device; iteratively determining a reference time delay, wherein the reference time delay is a time difference between sending the request and receiving the at least one pulse of the inbound location pulse sequence; and calibrating, to each reference time delay, to determine a calibrated time delay, wherein the calibrated time delay measures a steady state internal processing delay for the communication device; and determining, while the communication device is at the unknown distance from the reference device, the unknown distance using the calibrated time delay and a measured second time delay between the reference device transmitting a location request signal and receiving a location response signal. - View Dependent Claims (20)
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Specification