Patent US5995046A successfully refreshed from Google Patents.
US5995046A
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Radio geo-location system with advanced first received wavefront arrival determination
Assignee: Zebra Technologies Corp
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Filing: 1999-01-28
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Granted: 1999-11-30
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Expires: 2019-01-28
Abstract
Abstract An asset management radio location system uses time-of-arrival differentiation for random and repetitive spread spectrum, short duration pulse `blinks` from object-attached tags, to provide a practical, continuous identification of the location of each and every object within an environment of interest, irrespective whether the object is stationary or moving. Correlation-based RF processors determine which signals received spatially diverse antennas coupled to tag transmission readers are first-to-arrive signals as transmitted from any blinking tag. An object location processor carries out time-of-arrival differentiation of first-to-arrive transmissions from any blinking tag to determine where the respective object is located within the environment.
Inventors
- 👤 Donald K. Belcher
- 👤 Robert W. Boyd
- 👤 Michael A. Wohl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:11
CPC Classifications
G; G01; G01S; G01S5/00; G01S5/02; G01S5/06; G01S1/00; G01S1/02; G01S1/04; G01S1/042; G01S1/0428; G01S13/00; G01S13/74; G01S13/76; G01S13/767; G01S13/82; G01S13/87; G01S13/878; G01S5/0205; G01S5/021; G01S5/04; G06; G06K; G06K7/00; G06K7/0008; G06K7/10; G06K7/10009; G06K7/10019; G06K7/10079; G01S13/825
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
186 words
A system for identifying the locations of objects within a monitored environment, using time-of-arrival differentiation for transmissions from tags disposed with said objects, as detected at a plurality of spaced apart tag transmission monitoring locations for said monitored environment comprising: for each of said objects, a respective tag disposed therewith containing a tag transmitter which is operative to transmit a signal encoded with information representative of the identification of said each object; each of said plurality of spaced apart tag transmission monitoring locations having a plurality of mutually diverse antennas coupled to associated tag transmission readers which are operative to detect said signals transmitted by said tag transmitter; reader output processors operative to process signals detected by associated tag transmission readers and to determine which signals received by said tag transmission readers are first-to-arrive signals as transmitted from said tag transmitter; and an object location processor coupled to said reader output processors, and being operative to carry out time-of-arrival differentiation of said first-to-arrive signals transmitted from said tag transmitter as detected by said plurality of tag transmission readers, so to locate said object within said environment.
Claim 2
Independent Claim
186 words
A system for identifying the locations of objects within a monitored environment, using time-of-arrival differentiation for transmissions from tags disposed with said objects, as detected at a plurality of spaced apart tag transmission monitoring locations for said monitored environment comprising: for each of said objects, a respective tag disposed therewith containing a tag transmitter which is operative to transmit a signal encoded with information representative of the identification of said each object; each of said plurality of spaced apart tag transmission monitoring locations having a plurality of mutually diverse antennas coupled to associated tag transmission readers which are operative to detect said signals transmitted by said tag transmitter; reader output processors operative to process signals detected by associated tag transmission readers and to determine which signals received by said tag transmission readers are first-to-arrive signals as transmitted from said tag transmitter; and an object location processor coupled to said reader output processors, and being operative to carry out time-of-arrival differentiation of said first-to-arrive signals transmitted from said tag transmitter as detected by said plurality of tag transmission readers, so to locate said object within said environment.
Claim 3
Dependent Claim
37 words
A system according to claim 1, wherein said tag transmitter is operative to transmit said encoded signal in a random and repetitive manner that does not depend upon whether said object is in motion or is stationary.
Claim 4
Dependent Claim
36 words
A system according to claim 1, wherein said object location processor is operative to carry out said time-of-arrival differentiation of earliest-in-time ones of first-to-arrive signals detected by tag transmission readers of each of said monitoring locations.
Claim 5
Dependent Claim
65 words
A system according to claim 1, wherein said signals comprise spread spectrum RF signals, and wherein a respective reader processor comprises a matched filter correlator having a plurality of matched filter banks containing parallel correlators, which are operative to correlate a received spread spectrum RF signal with successive time offset versions of a reference spreading code corresponding to that of said spread spectrum RF signals.
Claim 6
Dependent Claim
73 words
A system according to claim 1, wherein said mutually diverse antennas of a respective monitoring location comprise spatially diverse antennas, that are spaced apart from one another by a distance sufficient to effectively statistically minimize destructive multipath interference at said antennas simultaneously, and wherein said antennas are spaced close enough to one another as to not significantly affect determination of the location of said object within said environment by said object location processor.
Claim 7
Dependent Claim
131 words
A system according to claim 1, further including, at each monitoring location, a plurality of auxiliary `phased array` signal processing paths coupled to said mutually diverse antennas to which said associated tag transmission readers are coupled, and wherein each auxiliary phased array path is configured to sum energy received from said antennas in a prescribed phase relationship, and to couple a respective energy sum to an associated tag transmission reader, and wherein a further reader output processor is coupled to said associated tag transmission readers, and is operative to process the energy sum supplied to said associated tag transmission reader and to generate a further first-to-arrive signal, and wherein said object location processor is operative to carry out time-of-arrival differentiation of earliest-in-time ones of signals provided by said tag transmission readers.
Claim 8
Independent Claim
169 words
A method for identifying locations of objects within a monitored environment, using time-of-arrival differentiation for a transmission from a tag disposed with one of said objects, as detected at a plurality of spaced apart tag transmission monitoring locations for said monitored environment comprising the steps of: (a) transmitting from a tag transmitter coupled with a respective one of said objects a signal encoded with information representative of the identification of said object; (b) at each of said plurality of spaced apart tag transmission monitoring locations, receiving said signal at a plurality of mutually diverse antennas; (c) coupling signals received by said plurality of mutually diverse antennas to associated tag transmission readers which are operative to detect said signal transmitted by said tag transmitter; (d) processing signals detected by said tag transmission readers and determine which signals received by said tag transmission readers are first-to-arrive signals as transmitted from said tag transmitter; and (e) conducting time-of-arrival differentiation processing of said first-to-arrive signals to locate said respective object within said environment.
Claim 9
Independent Claim
169 words
A method for identifying locations of objects within a monitored environment, using time-of-arrival differentiation for a transmission from a tag disposed with one of said objects, as detected at a plurality of spaced apart tag transmission monitoring locations for said monitored environment comprising the steps of: (a) transmitting from a tag transmitter coupled with a respective one of said objects a signal encoded with information representative of the identification of said object; (b) at each of said plurality of spaced apart tag transmission monitoring locations, receiving said signal at a plurality of mutually diverse antennas; (c) coupling signals received by said plurality of mutually diverse antennas to associated tag transmission readers which are operative to detect said signal transmitted by said tag transmitter; (d) processing signals detected by said tag transmission readers and determine which signals received by said tag transmission readers are first-to-arrive signals as transmitted from said tag transmitter; and (e) conducting time-of-arrival differentiation processing of said first-to-arrive signals to locate said respective object within said environment.
Claim 10
Dependent Claim
37 words
A method according to claim 7, wherein said tag transmitter is operative to transmit said encoded signal in a random and repetitive manner that does not depend upon whether said object is in motion or is stationary.
Claim 11
Dependent Claim
31 words
A method according to claim 7, wherein step (e) comprises conducting said time-of-arrival differentiation of earliest-in-time ones of first-to-arrive signals detected by tag transmission readers of each of said monitoring locations.
Claim 12
Dependent Claim
46 words
A method according to claim 7, wherein said signals comprise spread spectrum RF signals, and wherein step (d) comprises correlating a received spread spectrum RF signal with successive time offset versions of a reference spreading code corresponding to that of said transmitted spread spectrum RF signals.
Claim 13
Dependent Claim
73 words
A method according to claim 7, wherein said mutually diverse antennas of a respective monitoring location comprise spatially diverse antennas, that are spaced apart from one another by a distance sufficient to effectively statistically minimize destructive multipath interference at said antennas simultaneously, and wherein said antennas are spaced close enough to one another as to not significantly affect determination of the location of said respective tag and its associated object within said environment.
Claim 14
Dependent Claim
87 words
A method according to claim 7, wherein step (c) further comprises coupling a plurality of auxiliary `phased array` signal processing paths to said mutually diverse antennas, summing energy received from said antennas in a prescribed phase relationship, and coupling a respective energy sum to an associated tag transmission reader, step (d) further comprises processing the energy sum supplied to said associated tag transmission reader, and generating a further first-to-arrive signal, and step (e) further comprises conducting said time-of-arrival differentiation to includes said further earliest-in-time ones of signals.
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) | 2002-11-29 | 2003-05-31 | 2003-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-11-29 | 2007-05-31 | 2007-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-11-29 | 2011-05-31 | 2011-11-30 | $7700.00 | Window Closed / Lapsed |