Location system adapted for use in multipath environments
DCFirst Claim
1. A location system for locating objects within a tracking environment using time-of-arrival differentiation for electromagnetic transmissions received at multiple receivers, comprising:
- for each object, a TAG transmitter for transmitting, at selected intervals, TAG transmissions that include a unique TAG ID;
an array of receivers distributed within the tracking environment such that a TAG transmission is received by at least three receivers;
each receiver including a time-of-arrival circuit and a data communications controller;
the time-of-arrival circuit is responsive to the arrival of a TAG transmission for providing a TOA count corresponding to the time-of-arrival of the most direct path for such TAG transmission, with the TOA count being synchronized to a system synchronization clock provided to each receiver;
the data communications controller is responsive to the receipt of a TAG transmission for providing a corresponding TOA-detection packet that includes the associated TAG ID and TOA count; and
a location processor for receiving the TOA detection packets, and for determining the location of each TAG, and its associated object, from at least three corresponding TOA-detection packets received from different receivers.
1 Assignment
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Reexamination
Accused Products
Abstract
A radiolocation system for multipath environments, such as for tracking objects in a semiconductor fabrication facility (FIGS. 1a-1b), includes an array of receivers (20) distributed within the tracking area, coupled to a system processor (40) over a LAN. A TAG transmitter (30) located with each object transmits, at selected intervals, spread spectrum TAG transmissions including at least a unique TAG ID. In a high resolution embodiment, object location is accomplished by time-of-arrival (TOA) differentiation, with each receiver (FIG. 2b) including a TOA trigger circuit (64) for triggering on arrival of a TAG transmission, and a time base latching circuit (65) for latching the TOA count from an 800 MHz time base counter. In a low resolution embodiment, each receiver of the array is assigned a specific location-area, and receives TAG transmissions almost exclusively from TAGs located in that area, thereby eliminating the need for any time-of-arrival circuitry.
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Citations
60 Claims
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1. A location system for locating objects within a tracking environment using time-of-arrival differentiation for electromagnetic transmissions received at multiple receivers, comprising:
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for each object, a TAG transmitter for transmitting, at selected intervals, TAG transmissions that include a unique TAG ID; an array of receivers distributed within the tracking environment such that a TAG transmission is received by at least three receivers; each receiver including a time-of-arrival circuit and a data communications controller; the time-of-arrival circuit is responsive to the arrival of a TAG transmission for providing a TOA count corresponding to the time-of-arrival of the most direct path for such TAG transmission, with the TOA count being synchronized to a system synchronization clock provided to each receiver; the data communications controller is responsive to the receipt of a TAG transmission for providing a corresponding TOA-detection packet that includes the associated TAG ID and TOA count; and a location processor for receiving the TOA detection packets, and for determining the location of each TAG, and its associated object, from at least three corresponding TOA-detection packets received from different receivers. - 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)
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24. The location system of claim further comprising:
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at least one calibration transmitter, positioned at a known location, for transmitting calibration transmissions receivable by each of the receivers; each receiver being responsive to a calibration transmission for providing a corresponding calibration TOA detection packet, including the associated time-of-arrival TOA count, to the location processor; and the location processor determines calibration coefficients from the calibration TOA detection packets and the known locations of the receivers, and uses those coefficients to calibrate location computations from TOA-detection packets associated with TAG transmissions.
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25. A location system for locating objects within a tracking environment using area-detection by receivers that receive electromagnetic transmissions from assigned areas, comprising:
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for each object, a TAG transmitter for transmitting, at selected intervals, TAG transmissions that include a unique TAG ID; an array of receivers distributed within the tracking area, with each receiver being configured to receive TAG transmissions from an assigned area of a predetermined size; each receiver including a data communications controller responsive to the receipt of a TAG transmission for providing a corresponding area-detection packet that includes the received TAG ID; and a location processor for receiving the area-detection packets, and for determining the location of each TAG, and its associated object, based on the identity of the receiver receiving the TAG transmissions for that TAG. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A method for locating of objects within a tracking environment using time-of-arrival differentiation for electromagnetic transmissions received at multiple receivers, comprising the steps:
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for each object, transmitting, at selected intervals, TAG transmissions that include a unique TAG ID; providing an array of receivers distributed within the tracking environment such that a TAG transmission is received by at least three receivers; in response to the arrival of a TAG transmission at a receiver, providing a TOA count corresponding to the time-of-arrival of the most direct path for such TAG transmission, with the TOA count being synchronized to a system synchronization clock provided to each receiver; in response to the receipt of a TAG transmission, providing a corresponding TOA-detection packet that includes the associated TAG ID and TOA count; and using the TOA-detection packets, determining the location of each TAG, and its associated object, from at least three corresponding TOA-detection packets received from different receivers. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47)
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48. A method of locating objects within a tracking environment using area-detection by receivers that receive electromagnetic transmissions from assigned areas, comprising:
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for each object, providing a TAG transmitter for transmitting, at selected intervals, TAG transmissions that include a unique TAG ID; providing an array of receivers distributed within the tracking area, with each receiver being configured to receive TAG transmissions from an assigned area of a predetermined size; each receiver being responsive to the receipt of a TAG transmission for providing a corresponding area-detection packet that includes the received TAG ID; and determining the location of each TAG, and its associated object, based on the identity of the receiver receiving the TAG transmissions for that TAG as represented by the area-detection packet provided by such receiver that received the TAG transmissions. - View Dependent Claims (49, 50, 51, 52, 53, 54)
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57. the object is being moved..Iaddend..Iadd.64. The location system of claim 63, wherein TAG transmissions are transmitted at relatively short intervals while the object is in motion, and at relatively long intervals while the object is stationary..Iaddend..Iadd.65. A location system for locating objects within a tracking environment using area-detection by receivers that receive transmissions from assigned areas, comprising:
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for each object, a TAG transmitter for transmitting, at selected intervals, TAG transmissions that include a unique TAG ID; an array of receivers distributed within the tracking area, with each receiver being configured to receive TAG transmissions from an assigned area of a predetermined size; each receiver including a data communications controller responsive to the receipt of a TAG transmission for providing a corresponding area-detection packet that includes the received TAG ID; a location processor for receiving the area-detection packets, and for determining the location of each TAG, and its associated object, based on the identity of the receiver receiving the TAG transmissions for that TAG; and wherein each receiver provides an adjustable level of noise sensitivity for
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58. differentiating TAG transmissions from noise..Iaddend..Iadd.66. A location system for locating objects within a tracking environment using area-detection by receivers that receive transmissions from assigned areas, comprising:
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for each object, a TAG transmitter for transmitting at selected intervals, TAG transmissions that include a unique TAG ID; an array of receivers distributed within the tracking area, with each receiver being configured to receive TAG transmissions from an assigned area of a predetermined size; each receiver including a data communications controller responsive to the receipt of a TAG transmission for providing a corresponding area-detection packet that includes the received TAG ID; a location processor for receiving the area-detection packets, and for determining the location of each TAG, and its associated object, based on the identity of the receiver receiving the TAG transmissions for that TAG; and a local area network, said array of receivers being coupled to the location processor by said local area network, with each receiver including a LAN interface, such that the area detection packets are communicated to the location processor over said LAN..Iaddend..Iadd.67. A method of locating objects within a tracking environment using area-detection by receivers that receive transmissions from assigned areas, comprising; for each object, providing a TAG transmitter for transmitting, at selected intervals, TAG transmissions that include a unique TAG ID; providing an array of receivers distributed within the tracking area, with each receiver being configured to receive TAG transmissions from an assigned area of a predetermined size; each receiver being responsive to the receipt of a TAG transmission for providing a corresponding area-detection packet that includes the received TAG ID; determining the location of each TAG, and its associated object, based on the identity of the receiver receiving the TAG transmissions for that TAG as represented by the area-detection packet provided by such receiver that received the TAG transmissions; said receivers being distributed within the tracking environment with a predetermined spacing; and the transmitter power for each TAG transmitter and the spacing between adjacent receivers being cooperatively chosen such that a TAG transmission is almost always received by a single receiver to which the TAG is most proximate..Iaddend..Iadd.68. A method of locating objects within a tracking environment using area-detection by receivers that receive transmissions from assigned areas, comprising; for each object, providing a TAG transmitter for transmitting, at selected intervals, TAG transmissions that include a unique TAG ID; providing an array of receivers distributed within the tracking area, with each receiver being configured to receive TAG transmissions from an assigned area of a predetermined size; each receiver being responsive to the receipt of a TAG transmission for providing a corresponding area-detection packet that includes the received TAG ID; determining the location of each TAG, and its associated object, based on the identity of the receiver receiving the TAG transmissions for that TAG as represented by the area-detection packet provided by such receiver that received the TAG transmissions; and wherein the set of transmitting TAG transmissions further comprises detecting the motion of the object, and enabling TAG transmissions while
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59. the object is in motion..Iaddend..Iadd.69. The location method of claim 68, wherein each TAG transmission includes an appropriate motion status indication..Iaddend..Iadd.70. A method of locating objects within a tracking environment using area-detection by receivers that receive transmissions from assigned areas, comprising:
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for each object, providing a TAG transmitter for transmitting, at selected intervals, TAG transmissions that include a unique TAG ID; providing an array of receivers distributed within the tracking area, with each receiver being configured to receive TAG transmissions from an assigned area of a predetermined size; each receiver being responsive to the receipt of a TAG transmission for providing a corresponding area-detection packet that includes the received TAG ID; determining the location of each TAG, and its associated object, based on the identity of the receiver receiving the TAG transmissions for that TAG as represented by the area-detection packet provided by such receiver that received the TAG transmissions; and wherein the step of transmitting TAG transmissions comprises the step of transmitting TAG transmissions at selected intervals each time an object - View Dependent Claims (55, 56, 60)
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Specification