Method and apparatus for location estimation
First Claim
1. A method of estimating unknown locations of wireless devices, the method including the steps of:
- receiving a measurement of a first signal transmitted between the first and the second wireless devices to obtain a signal measurement, and optimizing a function that depends on the signal measurement, a set of postulated coordinates for the first wireless device, and a set of postulated coordinates for the second wireless devices.
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Accused Products
Abstract
A system for locating a number of devices (112-130) by measuring signals transmitted between known location devices (112-118, 134-138, 214-218, 224-228) and unknown location devices (120-130, 222), and signals transmitted between pairs of unknown location devices (120-130, 222), entering signal measurements into a graph function that includes a number of first sub-expressions, a number of which include signal measurement prediction sub-expressions, and have extrema when a predicted signal measurement is equal to an actual signal measurement, and optimizing the graph function.
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Citations
51 Claims
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1. A method of estimating unknown locations of wireless devices, the method including the steps of:
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receiving a measurement of a first signal transmitted between the first and the second wireless devices to obtain a signal measurement, and optimizing a function that depends on the signal measurement, a set of postulated coordinates for the first wireless device, and a set of postulated coordinates for the second wireless devices. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 39)
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38. A processing node comprising:
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a receiver for receiving a first result of a first signal measurement of a first signal transmitted between a first unknown location device and a second unknown location device, and a second result of a second signal measurement of a second signal transmitted between the second unknown location device and a known location device, a processor for optimizing a function of the first signal measurement, the second signal measurement, postulated coordinates of the first unknown location device, and the second unknown location device in terms of postulated coordinates of the first unknown location device, and the second unknown location device, whereby locations of the first and second unknown location devices are estimated.
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40. A location estimation system comprising:
a plurality of wireless devices, each comprising;
a signal measurer, and a transmitter for transmitting a signal measurement, and a processing node comprising;
a receiver for receiving a first result of a first signal measurement of a first signal transmitted between a first unknown location device and a second unknown location wireless device, a second result of a second signal measurement of a second signal transmitted between the second unknown location wireless device and a known location device, and a processor for optimizing a function of the first signal measurement, the second signal measurement, postulated coordinates of the first unknown location device, and the second unknown location device in terms of postulated coordinates of the first unknown location device, and the second unknown location device.
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41. A method of responding to a two-way time of arrival signal the method comprising the steps of:
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receiving a pseudo random sequence having a first duration, phase locking a clock to a frequency of the pseudo random sequence, waiting a random multiple of the first duration as measured using the clock, and transmitting the pseudo random sequence.
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42. A method of measuring a distance to a remote transceiver, the method comprising the steps of:
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transmitting a pseudo random sequence of a first duration at a first time, receiving the pseudo random sequence after a second duration counted from the first time that is larger than the first duration, and comparing the phase of a received pseudo random sequence to the phase of a locally generated pseudo random sequence. - View Dependent Claims (44, 45, 46, 48, 49, 50, 51)
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43. A transceiver comprising:
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a means for measuring a plurality of signals received form a plurality of transceivers to obtain a plurality of signal measurement;
a means for communicatively coupling the plurality of signal measurement to a processing node.
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47. A computer readable medium containing programming instructions for of estimating locations of a set of wireless devices including a first wireless device and a second wireless device the locations of which are unknown, the computer readable medium including programming instructions for:
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receiving a measurement of a first signal transmitted between the first and the second wireless devices to obtain a signal measurement, and optimizing a function that depends on the signal measurement, a set of postulated coordinates for the first device, and a set of postulated coordinates for the second wireless devices.
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Specification