Patent US6665333B2 successfully refreshed from Google Patents.
US6665333B2
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Methods and apparatus for determining the time of arrival of a signal
Assignee: ITT Manufacturing Enterprises LLC
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Filing: 2002-04-29
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Granted: 2003-12-16
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Expires: 2022-04-29
Abstract
Abstract A spread spectrum position location communication system determines the position of a mobile master radio using a round-trip messaging scheme in which the time of arrive (TOA) of ranging messages is accurately determined to yield the range estimates required to calculate the position of the mobile radio via trilateration. The master radio transmits outbound ranging messages to plural reference radios which respond by transmitting reply ranging messages. Upon reception of the reply ranging message, the master radio determines the range to the reference radio from the signal propagation time calculated by subtracting the far-end turn around time from the round-trip elapsed time. Any combination of fixed or mobile radios of known positions can be used as the reference radios for another mobile radio in the system, thereby providing adaptability under varying transmission conditions. The individual radios do not need to be synchronized to a common time reference, thereby eliminating the need for highly accurate system clocks. By performing internal delay calibration, errors caused by difficult-to-predict internal transmitter and receiver delay variations can be minimized. Leading-edge-of-the-signal curve fitting and frequency diversity techniques minimize the effects of multipath interference on TOA estimates.
Inventors
- 👤 Dennis D. McCrady
- 👤 Lawrence J. Doyle
- 👤 Howard Forstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:02
CPC Classifications
H; H04; H04W; H04W64/00; G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/46; G01S5/00; G01S5/02; G01S5/0205; G01S5/021; G01S5/0218; G01S5/0244; G01S5/14; G01S5/18; G01S5/30; G01S2013/466; G01S5/0294
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
92 words
A carrier signal having signal acquisition information embedded therein for determining a time of arrival of the carrier signal, comprising: a first sequence comprising a plurality of first spread spectrum symbols for detecting arrival of the carrier signal, each of said first spread spectrum symbols comprising a plurality of chips; and a second sequence comprising at least one spread spectrum symbol for determining a time of arrival of the carrier signal, said at least one spread spectrum symbol comprising a greater number of chips than each of said first spread spectrum symbols.
Claim 2
Dependent Claim
92 words
A carrier signal having signal acquisition information embedded therein for determining a time of arrival of the carrier signal, comprising: a first sequence comprising a plurality of first spread spectrum symbols for detecting arrival of the carrier signal, each of said first spread spectrum symbols comprising a plurality of chips; and a second sequence comprising at least one spread spectrum symbol for determining a time of arrival of the carrier signal, said at least one spread spectrum symbol comprising a greater number of chips than each of said first spread spectrum symbols.
Claim 3
Dependent Claim
39 words
The carrier signal of claim 1 , wherein said at least one spread spectrum symbol of said second sequence comprises a greater number of chips than a sum of the chips of all of said first spread spectrum symbols.
Claim 4
Dependent Claim
21 words
The carrier signal of claim 1 , wherein said second sequence comprises a greater number of chips than said first sequence.
Claim 5
Dependent Claim
30 words
The carrier signal of claim 1 , wherein said carrier signal is configured to be used in a communication system employing a carrier sense multiple access—collision avoidance (CSMA-CA) messaging protocol.
Claim 6
Dependent Claim
12 words
The carrier signal of claim 1 , further comprising a data portion.
Claim 7
Independent Claim
100 words
A method of acquiring a transmitted signal including a first acquisition portion and a second acquisition portion, comprising: (a) detecting arrival of the transmitted signal from the first acquisition portion, wherein the first acquisition portion comprises a plurality of first spread spectrum symbols each including a plurality of chips; and (b) determining a time of arrival of the transmitted signal from the second acquisition portion in response to detecting arrival of the transmitted signal, wherein the second acquisition portion comprises at least one spread spectrum symbol including a greater number of chips than each of the first spread spectrum symbols.
Claim 8
Independent Claim
100 words
A method of acquiring a transmitted signal including a first acquisition portion and a second acquisition portion, comprising: (a) detecting arrival of the transmitted signal from the first acquisition portion, wherein the first acquisition portion comprises a plurality of first spread spectrum symbols each including a plurality of chips; and (b) determining a time of arrival of the transmitted signal from the second acquisition portion in response to detecting arrival of the transmitted signal, wherein the second acquisition portion comprises at least one spread spectrum symbol including a greater number of chips than each of the first spread spectrum symbols.
Claim 9
Dependent Claim
44 words
The method of claim 6 , wherein (a) includes applying a first digital matched filter to the first acquisition portion, and (b) includes applying a second digital matched filter, of a greater length than the first digital matched filter, to the second acquisition portion.
Claim 10
Dependent Claim
35 words
The method of claim 6 , wherein a determination of the time of arrival of the transmitted signal is attempted only in response to being triggered by detection of an arrival of the transmitted signal.
Claim 11
Independent Claim
111 words
An apparatus for detecting a transmitted signal including a first acquisition portion and a second acquisition portion, comprising: an acquisition processor configured to detect an arrival of the first acquisition portion of the transmitted signal, wherein the first acquisition portion comprises a plurality of first spread spectrum symbols each including a plurality of chips; and a time of arrival processor configured to determine a time of arrival of the transmitted signal from the second acquisition portion in response to detection of the first acquisition portion, wherein the second acquisition portion comprises at least one spread spectrum symbol including a greater number of chips than each of the first spread spectrum symbols.
Claim 12
Independent Claim
111 words
An apparatus for detecting a transmitted signal including a first acquisition portion and a second acquisition portion, comprising: an acquisition processor configured to detect an arrival of the first acquisition portion of the transmitted signal, wherein the first acquisition portion comprises a plurality of first spread spectrum symbols each including a plurality of chips; and a time of arrival processor configured to determine a time of arrival of the transmitted signal from the second acquisition portion in response to detection of the first acquisition portion, wherein the second acquisition portion comprises at least one spread spectrum symbol including a greater number of chips than each of the first spread spectrum symbols.
Claim 13
Dependent Claim
29 words
The apparatus of claim 9 , wherein said time of arrival processor determines the time of arrival of the transmitted signal with a greater accuracy than said acquisition processor.
Claim 14
Dependent Claim
39 words
The apparatus of claim 9 , wherein said acquisition processor comprises a digital matched filter of a first length and said time of arrival processor comprises a digital matched filter of a second length greater than the first length.
Claim 15
Dependent Claim
35 words
The apparatus of claim 9 , wherein said time of arrival processor determines the time of arrival of the transmitted signal only in response to said acquisition processor detecting an arrival of the transmitted signal.
Claim 16
Dependent Claim
26 words
The apparatus of claim 9 , wherein said acquisition processor triggers said time of arrival processor to determine the time of arrival of the transmitted signal.
Claim 17
Dependent Claim
14 words
The apparatus of claim 9 , wherein said apparatus is a mobile communication device.
Claim 18
Dependent Claim
21 words
The carrier signal of claim 1 , wherein the carrier signal, including the first and second sequences, has a predetermined bandwidth.
Claim 19
Dependent Claim
18 words
The carrier signal of claim 1 , wherein the first and second sequences have a same chip rate.
Claim 20
Dependent Claim
25 words
The carrier signal of claim 1 , wherein said carrier signal is configured to be used in a communication system employing a round-trip ranging scheme.
Claim 21
Dependent Claim
21 words
The method of claim 6 , wherein the transmitted signal, including the first and second acquisition portions, has a predetermined bandwidth.
Claim 22
Dependent Claim
18 words
The method of claim 6 , wherein the first and second acquisition portions have a same chip rate.
Claim 23
Dependent Claim
24 words
The method of claim 6 , wherein the transmitted signal is received in accordance with a carrier sense multiple access—collision avoidance (CSMA-CA) messaging protocol.
Claim 24
Dependent Claim
19 words
The method of claim 6 , wherein the transmitted signal is received in accordance with a round-trip ranging scheme.
Claim 25
Dependent Claim
21 words
The apparatus of claim 9 , wherein the transmitted signal, including the first and second acquisition portions, has a predetermined bandwidth.
Claim 26
Dependent Claim
18 words
The apparatus of claim 9 , wherein the first and second acquisition portions have a same chip rate.
Claim 27
Dependent Claim
25 words
The apparatus of claim 9 , wherein the apparatus receives the transmitted signal in accordance with a carrier sense multiple access—collision avoidance (CSMA-CA) messaging protocol.
Claim 28
Dependent Claim
20 words
The apparatus of claim 9 , wherein the apparatus receives the transmitted signal in accordance with a round-trip ranging scheme.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2006-12-15 | 2007-06-16 | 2007-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2010-12-15 | 2011-06-16 | 2011-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2014-12-15 | 2015-06-16 | 2015-12-16 | $7700.00 | Window Closed / Lapsed |