Method for tracking the location of mobile units
First Claim
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1. A method for continuous tracking the location of mobile units, comprising the steps of:
- providing at least one mobile unit having a wireless transceiver and a unique address;
providing at least one stationary base unit having a phase array antenna with three or more single antenna elements, where said stationary base unit periodically polls said at least one mobile unit to trigger transmission of at least one signal from said mobile unit to said stationary base unit;
receiving said signal, including an address from said mobile unit at said stationary base unit via said phase array antenna;
measuring the phase difference of said signal arriving at said three or more antenna elements of said phase array antenna;
performing calculations by expressing the phase difference at a plurality of points of location of said antenna elements of said stationary base unit relative to at least one other point of location of another antenna element of the same stationary base unit; and
determining the location of each at least one mobile unit using a single one of the at least one stationary unit by determining azimuths of each mobile unit from the phase differences at a plurality of points of said single antenna elements of the single base unit and calculating the polar coordinates of intersections of the azimuths.
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Abstract
A method for tracking the location of mobile units, comprises providing a plurality of mobile units each having a wireless transmitter and a unique address and at least one stationary base unit having a phase array antenna with antenna elements. A signal including an address is received from at least one mobile unit by the at least base unit via the phase array antenna. The phase difference of the signal arriving at the antenna elements from each mobile unit is measured and the coordinates of the location of each mobile unit are calculated as a function of the phase differences.
46 Citations
21 Claims
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1. A method for continuous tracking the location of mobile units, comprising the steps of:
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providing at least one mobile unit having a wireless transceiver and a unique address;
providing at least one stationary base unit having a phase array antenna with three or more single antenna elements, where said stationary base unit periodically polls said at least one mobile unit to trigger transmission of at least one signal from said mobile unit to said stationary base unit;
receiving said signal, including an address from said mobile unit at said stationary base unit via said phase array antenna;
measuring the phase difference of said signal arriving at said three or more antenna elements of said phase array antenna;
performing calculations by expressing the phase difference at a plurality of points of location of said antenna elements of said stationary base unit relative to at least one other point of location of another antenna element of the same stationary base unit; and
determining the location of each at least one mobile unit using a single one of the at least one stationary unit by determining azimuths of each mobile unit from the phase differences at a plurality of points of said single antenna elements of the single base unit and calculating the polar coordinates of intersections of the azimuths. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
measuring the phase difference between the signal arriving at each of a plurality of antenna element from at least one portable reference transceiver; performing calculations at said stationary base unit by expressing the phase difference at a plurality of points of location of said antenna elements of said stationary base unit relative to at least one other point of location of another antenna element of the same stationary base unit;
determining from said phase differences the coordinates of location of said portable reference transceiver; and
correcting future calculations of the coordinates of at least one mobile unit by the difference between the calculated coordinates of said portable reference transceiver and the actual location of said portable reference transceiver.
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13. The method according to claim 12, wherein said portable reference transceiver has at least one sensor.
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14. A method for calibrating a system for continuous tracking the location of mobile units, comprising the steps of:
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providing at least one stationary base unit with a phase array antenna having antenna elements for receiving signals from a plurality of mobile wireless transceiver units and at least one wireless portable reference transceiver disposed at a fixed location and having a unique identifying address;
receiving a signal including an address from said wireless portable reference transceiver at said stationary base unit via a phase array antenna;
measuring the phase difference of said signal arriving at a plurality of antenna elements of said phase array antenna;
performing calculations by expressing the phase difference at a plurality of points of location of said antenna elements of said stationary base unit relative to at least one other point of location of another antenna element of the same stationary base unit;
determining from said phase differences the coordinates of location of said portable reference transceiver; and
correcting future calculations of the coordinates of the mobile wireless transceiver units by the difference between the calculated coordinates of said portable reference transceiver and the actual location of said portable reference transceiver. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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Specification