Patent US3635214A successfully refreshed from Google Patents.
US5119104A
Expired / Lapsed
US
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Location system adapted for use in multipath environments
Assignee: Precision Tracking Inc
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Filing: 1990-05-04
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Granted: 1992-06-02
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Expires: 2010-05-04
Abstract
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.
Inventors
- 👤 Alan C. Heller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:24
CPC Classifications
G; G01; G01S; G01S5/00; G01S5/02; G01S5/06; G01S5/0295; G06; G06K; G06K7/00; G06K7/0008; G07; G07C; G07C9/00; G07C9/20; G07C9/28
Claims Analysis
Total Claims: 58
Claim 1
Independent Claim
178 words
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.
Claim 2
Dependent Claim
178 words
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.
Claim 3
Dependent Claim
15 words
The location system of claim 1, wherein spread spectrum communications is used for TAG transmissions.
Claim 4
Dependent Claim
19 words
The location system of claim 2, wherein the spread spectrum communications are in the frequency range of 900 Mhz.
Claim 5
Dependent Claim
17 words
The location system of claim 2, wherein the duration of a TAG transmission is around 600 microseconds.
Claim 6
Dependent Claim
14 words
The location system of claim 1, wherein each TAG transmission includes selected status information.
Claim 7
Dependent Claim
16 words
The location system of claim 5, wherein the selected status information is generated without operator intervention.
Claim 8
Dependent Claim
37 words
The location system of claim 1, wherein the TAG transmitter includes a motion detection circuit for detecting motion of the object, and for enabling the TAG transmitter to transmit TAG transmissions while the object is in motion.
Claim 9
Dependent Claim
31 words
The location system of claim 7, wherein TAG transmissions are transmitted only while the object is in motion and for a relatively short predetermined period of time after motion has ceased.
Claim 10
Dependent Claim
16 words
The location system of claim 8, wherein each TAG transmission includes an appropriate motion status indication.
Claim 11
Dependent Claim
27 words
The location system of claim 9, wherein each TAG transmission includes the appropriate one of at least three motion status indications: Motion Initiated, Motion Continuing, Motion Stopped.
Claim 12
Dependent Claim
34 words
The location system of claim 1, wherein the TAG transmitter includes a periodicity control circuit for causing the TAG transmitter to transmit TAG transmissions at selected intervals each time the object is being moved.
Claim 13
Dependent Claim
31 words
The location system of claim 11, 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.
Claim 14
Dependent Claim
23 words
The location system of claim 1, wherein the time-of-arrival circuit provides an adjustable level of noise sensitivity for differentiating TAG transmissions from noise.
Claim 15
Dependent Claim
23 words
The location system of claim 13, wherein noise sensitivity is determined by a selected signal level threshold and a selected signal duration threshold.
Claim 16
Dependent Claim
50 words
The location system of claim 1, wherein the time-of-arrival circuit comprises: a TOA trigger circuit for providing a TOA-DETECT trigger immediately upon arrival of a direct-path TAG transmission; and a time base latching circuit responsive to the TOA-DETECT trigger for latching the associated TOA count of the synchronized time base.
Claim 17
Dependent Claim
38 words
The location system of claim 15, wherein the TOA trigger circuit provides the TOA-DETECT trigger when a the signal level of a received signal exceeds a signal-level threshold, thereby indicating that the received signal is a TAG transmission.
Claim 18
Dependent Claim
32 words
The location system of claim 16, wherein the TOA trigger circuit includes a comparator for providing a TOA-DETECT trigger when the signal level of a received signal exceeds a comparator reference level.
Claim 19
Dependent Claim
14 words
The location system of claim 17, wherein the signal-level comparator reference level is adjustable.
Claim 20
Dependent Claim
33 words
The location system of claim 15, wherein the time base latching circuit indicates when the duration of the received signal exceeds a signal-duration threshold, thereby designating the received signal as a TAG transmission.
Claim 21
Dependent Claim
42 words
The location system of claim 19, wherein: the TOA-DETECT trigger remains asserted during receipt of a TAG transmission; and the time base latching circuit provides the signal-duration indication when the duration of the TOA-DETECT trigger exceeds a selected MAX NOISE LENGTH count.
Claim 22
Dependent Claim
34 words
The location system of claim 15, wherein the time base latching circuit includes a time base counter that counts at a rate of around 800 MHz and is derived from the system synchronization signal.
Claim 23
Dependent Claim
42 words
The location system of claim 1, wherein the receivers are coupled to the location processor by a local area network, with each receiver including a LAN interface, such that the TOA detection packets are communicated to the location processor over the LAN.
Claim 24
Dependent Claim
20 words
The location system of claim 22, wherein the system synchronization clock signal is communicated to each receiver over the LAN.
Claim 25
Dependent Claim
88 words
The location system of claim further comprising: 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.
Claim 26
Dependent Claim
129 words
A location system for locating objects within a tracking environment using area-detection by receivers that receive electromagnetic transmissions from assigned areas, 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 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.
Claim 27
Dependent Claim
129 words
A location system for locating objects within a tracking environment using area-detection by receivers that receive electromagnetic transmissions from assigned areas, 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 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.
Claim 28
Dependent Claim
29 words
The location system of claim 25, wherein each receiver includes a directional antenna with a predetermined beamwidth, such that the receiver receives TAG transmissions originating from its assigned area.
Claim 29
Dependent Claim
56 words
The location system of claim 25, wherein: the receivers are distributed within the tracking environment with a predetermined spacing; and the transmitter power for each TAG transmitter and the spacing between adjacent receivers are cooperatively chosen such that a TAG transmission is almost always received by a single receiver to which the TAG is most proximate.
Claim 30
Dependent Claim
16 words
The location system of claim 25, wherein spread spectrum communications is used for the TAG transmissions.
Claim 31
Dependent Claim
19 words
The location system of claim 28, wherein the spread spectrum communications are in the frequency range of 900 Mhz.
Claim 32
Dependent Claim
17 words
The location system of claim 28, wherein the duration of a TAG transmission is around 600 microseconds.
Claim 33
Dependent Claim
37 words
The location system of claim 25, wherein the TAG transmitter includes a motion detection circuit for detecting motion of the object, and for enabling the TAG transmitter to transmit TAG transmissions while the object is in motion.
Claim 34
Dependent Claim
31 words
The location system of claim 31, wherein TAG transmissions are transmitted only while the object is in motion and for a relatively short predetermined period of time after motion has ceased.
Claim 35
Dependent Claim
16 words
The location system of claim 32, wherein each TAG transmission includes an appropriate motion status indication.
Claim 36
Dependent Claim
27 words
The location system of claim 33, wherein each TAG transmission includes the appropriate one of at least three motion status indications: Motion Initiated, Motion Continuing, Motion Stopped.
Claim 37
Dependent Claim
34 words
The location system of claim 25, wherein the TAG transmitter includes a periodicity control circuit for causing the TAG transmitter to transmit TAG transmissions at selected intervals each time the object is being moved.
Claim 38
Dependent Claim
31 words
The location system of claim 35, 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.
Claim 39
Dependent Claim
22 words
The location system of claim 25, wherein each receiver provides an adjustable level of noise sensitivity for differentiating TAG transmissions from noise.
Claim 40
Dependent Claim
23 words
The location system of claim 37, wherein noise sensitivity is determined by a selected signal level threshold and a selected signal duration threshold.
Claim 41
Dependent Claim
42 words
The location system of claim 25, wherein the receivers are coupled to the location processor by a local area network, with each receiver including a LAN interface, such that the area detection packets are communicated to the location processor over the LAN.
Claim 42
Independent Claim
153 words
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: 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.
Claim 43
Independent Claim
153 words
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: 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.
Claim 44
Dependent Claim
31 words
The location method of claim 40, wherein the step of transmitting TAG transmissions further comprises detecting the motion of the object, and enabling TAG transmissions while the object is in motion.
Claim 45
Dependent Claim
16 words
The location method of claim 41, wherein each TAG transmission includes an appropriate motion status indication.
Claim 46
Dependent Claim
30 words
The location method of claim 40, wherein the step of transmitting TAG transmissions comprises the step of transmitting TAG transmissions at selected intervals each time an object is being moved.
Claim 47
Dependent Claim
31 words
The location method of claim 40, further comprising the step of adjusting receiver noise sensitivity using a signal level threshold and a signal duration threshold to differentiate TAG transmissions from noise.
Claim 48
Dependent Claim
52 words
The location method of claim 40, wherein the step of providing the TOA count comprises the steps: providing a TOA-DETECT trigger immediately upon arrival of a direct-path TAG transmission; and in response to the TOA-DETECT trigger, latching the associated TOA count of a time base counter derived from the system synchronism clock.
Claim 49
Dependent Claim
42 words
The location method of claim 40, wherein the receivers are coupled to the location processor by a local area network, with each receiver including a LAN interface, such that the TOA detection packets are communicated to the location processor over the LAN.
Claim 50
Dependent Claim
82 words
The location method of claim 40, further comprising the steps: transmitting calibration transmissions from at least one known location receivable by each of the receivers; in response to the receipt of a calibration transmission at a receiver, providing a corresponding calibration TOA detection packet, including the associated time-of-arrival TOA count; and determining calibration coefficients from the calibration TOA detection packets and the known locations of the receivers, and using those coefficients to calibrate location computations from TOA-detection packets associated with TAG transmissions.
Claim 51
Independent Claim
131 words
A method of locating objects within a tracking environment using area-detection by receivers that receive electromagnetic 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; 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.
Claim 52
Independent Claim
131 words
A method of locating objects within a tracking environment using area-detection by receivers that receive electromagnetic 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; 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.
Claim 53
Dependent Claim
28 words
The method of claim 48, wherein each receiver includes a directional antenna with a predetermined beamwidth, such that the receiver receives TAG transmissions originating from its assigned area.
Claim 54
Dependent Claim
55 words
The method of claim 48, wherein: the receivers are distributed within the tracking environment with a predetermined spacing; and the transmitter power for each TAG transmitter and the spacing between adjacent receivers are cooperatively chosen such that a TAG transmission is almost always received by a single receiver to which the TAG is most proximate.
Claim 55
Dependent Claim
31 words
The location method of claim 48, wherein the set of transmitting TAG transmissions further comprises detecting the motion of the object, and enabling TAG transmissions while the object is in motion.
Claim 56
Dependent Claim
16 words
The location method of claim 51, wherein each TAG transmission includes an appropriate motion status indication.
Claim 57
Dependent Claim
30 words
The location method of claim 48, wherein the step of transmitting TAG transmissions comprises the step of transmitting TAG transmissions at selected intervals each time an object is being moved.
Claim 58
Dependent Claim
42 words
The location method of claim 48, wherein the receivers are coupled to the location processor by a local area network, with each receiver including a LAN interface, such that the TOA detection packets are communicated to the location processor over the LAN.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-06-02 | 1995-12-02 | 1996-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-02 | 1999-12-02 | 2000-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-02 | 2003-12-02 | 2004-06-02 | $7700.00 | Window Closed / Lapsed |