Patent US6091362A successfully refreshed from Google Patents.
US6091362A
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Bandwidth synthesis for wireless location system
Assignee: Qualcomm Inc
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Filing: 1999-01-12
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Granted: 2000-07-18
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Expires: 2019-01-12
Abstract
Abstract A wireless location system receives signals transmitted by wireless telephones at a plurality of signal collection sites. To improve the accuracy of the location information, the system synthesizes greater bandwidth, and thus greater time resolution, than would otherwise be available. The location system commands an MTSO to make the wireless transmitter to be located change frequency channels, and a doubly-differenced carrier phase of the transmitted signal, or the time difference of arrival, is observed at each of many frequencies spanning the widest possible bandwidth. The phase-measurement data from these many frequencies are combined to resolve the inherent integer-wavelength ambiguity. To begin the process of ambiguity resolution, single-frequency channel, doubly-differenced, group delay measurements are used to resolve the ambiguity in the doubly-differenced phase difference between the most closely spaced frequency channels. The invention may be utilized to obtain a bandwidth greater than the typical 20 KHz bandwidth of the signals to be cross-correlated (in either the time or frequency domains) in a cellular telephone location application, With such bandwidth synthesis, up to the 12.5 MHz bandwidth allocated by the FCC to each cellular system operator may be exploited for location purposes.
Inventors
- 👤 Louis A. Stilp
- 👤 Charles C. Counselman, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:43
CPC Classifications
H; H04; H04W; H04W64/00; G; G01; G01S; G01S5/00; G01S5/02; G01S5/10; G01S5/0205; G01S5/021; G01S5/0284; G01S5/06; G01S1/00; G01S1/02; G01S1/022; G01S1/026; G01S2205/00; G01S2205/001; G01S2205/006; G01S2205/008; G01S2205/01; G01S2205/06; G01S5/0215; G01S5/0218; G01S5/0221; G01S5/02213; G01S5/02216; G01S5/0244; G01S5/0246; G01S5/0252; G01S5/02521; G01S5/0257; G01S5/0268; H04W4/00; H04W4/90; H04W76/00; H04W76/50; Y; Y02; Y02D; Y02D30/00; Y02D30/70
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
138 words
A wireless location system for estimating the geographic location of a mobile transmitter, wherein said mobile transmitter is operative to transmit narrowband signals at frequencies spanning a predefined wide band of frequencies, and wherein said predefined wide band of frequencies is wider than the bandwidth of the individual narrowband signals transmitted by said mobile transmitter, comprising: (a) at least three geographically separated receivers for receiving the narrowband signals transmitted by said mobile transmitter; (b) bandwidth synthesis means for effecting the transmission by said mobile transmitter of narrowband signals at a plurality of frequencies spanning said predefined wide band of frequencies; (c) means for resolving integer cycle ambiguity in phase relationships between the plurality of transmitted narrowband signals; and (d) time difference of arrival means for determining the location of said mobile transmitter using the plurality of narrowband signals.
Claim 2
Dependent Claim
138 words
A wireless location system for estimating the geographic location of a mobile transmitter, wherein said mobile transmitter is operative to transmit narrowband signals at frequencies spanning a predefined wide band of frequencies, and wherein said predefined wide band of frequencies is wider than the bandwidth of the individual narrowband signals transmitted by said mobile transmitter, comprising: (a) at least three geographically separated receivers for receiving the narrowband signals transmitted by said mobile transmitter; (b) bandwidth synthesis means for effecting the transmission by said mobile transmitter of narrowband signals at a plurality of frequencies spanning said predefined wide band of frequencies; (c) means for resolving integer cycle ambiguity in phase relationships between the plurality of transmitted narrowband signals; and (d) time difference of arrival means for determining the location of said mobile transmitter using the plurality of narrowband signals.
Claim 3
Dependent Claim
46 words
A system as recited in claim 1, wherein said bandwidth synthesis means includes an operative coupling between the wireless location system and a wireless mobile telephone switching office for effecting the switching of said mobile transmitter from a first narrowband frequency to a second narrowband frequency.
Claim 4
Dependent Claim
62 words
A system as recited in claim 2, wherein the operative coupling for said bandwidth synthesis means includes means for the wireless location system to predefine which narrowband frequencies are to be used by said mobile transmitter and means for the mobile telephone switching office to report back to the wireless location system which narrowband channels have been used by the mobile transmitter.
Claim 5
Dependent Claim
69 words
A system as recited in claim 1, wherein said means for resolving integer cycle ambiguity in phase relationships between the plurality of transmitted narrowband signals caused by the bandwidth synthesis means includes means to solve the equation φ=-fτ+n, where φ is measured in cycles, f in Hz and τ in seconds; and n is an integer representing the intrinsic integer-cycle ambiguity of a time difference of arrival phase measurement.
Claim 6
Dependent Claim
27 words
A system as recited in claim 1, wherein said wireless location system includes a calibration transmitter so that the time difference of arrival means is doubly differenced.
Claim 7
Dependent Claim
29 words
A system as recited in claim 1, wherein said bandwidth synthesis means includes means for determining a wideband phase versus frequency characteristic of the transmissions from said mobile transmitter.
Claim 8
Independent Claim
126 words
A method for estimating the geographic location of a mobile transmitter, wherein said mobile transmitter is operative to transmit narrowband signals at frequencies spanning a predefined wide band of frequencies, and wherein said predefined wide band of frequencies is wider than the bandwidth of the individual narrowband signals transmitted by said mobile transmitter, comprising the steps of: (a) receiving the narrowband signals transmitted by said mobile transmitter at three geographically separated receiver sites; (b) effecting the transmission by said mobile transmitter of narrowband signals at a plurality of frequencies spanning said predefined wide band of frequencies; (c) resolving integer cycle ambiguity in phase relationships between the plurality of transmitted narrowband signals; and (d) determining the location of said mobile transmitter using the plurality of narrowband signals.
Claim 9
Independent Claim
126 words
A method for estimating the geographic location of a mobile transmitter, wherein said mobile transmitter is operative to transmit narrowband signals at frequencies spanning a predefined wide band of frequencies, and wherein said predefined wide band of frequencies is wider than the bandwidth of the individual narrowband signals transmitted by said mobile transmitter, comprising the steps of: (a) receiving the narrowband signals transmitted by said mobile transmitter at three geographically separated receiver sites; (b) effecting the transmission by said mobile transmitter of narrowband signals at a plurality of frequencies spanning said predefined wide band of frequencies; (c) resolving integer cycle ambiguity in phase relationships between the plurality of transmitted narrowband signals; and (d) determining the location of said mobile transmitter using the plurality of narrowband signals.
Claim 10
Dependent Claim
38 words
A method as recited in claim 7, wherein step (b) includes the use of a wireless mobile telephone switching office for effecting the switching of said mobile transmitter from a first narrowband frequency to a second narrowband frequency.
Claim 11
Dependent Claim
45 words
A method as recited in claim 8, wherein step (b) further comprises predefining which narrowband frequencies are to be used by said mobile transmitter and receiving from the mobile telephone switching office a report of which narrowband channels have been used by the mobile transmitter.
Claim 12
Dependent Claim
46 words
A method as recited in claim 7, wherein step (c) includes solving the equation, φ=-fτ+n, where φ is measured in cycles, f in Hz and τ in seconds, and n is an integer representing the intrinsic integer-cycle ambiguity of a time difference of arrival phase measurement.
Claim 13
Dependent Claim
26 words
A method as recited in claim 7, further comprising the step of employing a calibration transmitter to obtain a doubly differenced time difference of arrival measurement.
Claim 14
Dependent Claim
23 words
A method as recited in claim 7, further comprising determining a wideband phase versus frequency characteristic of the transmissions from said mobile transmitter.
Claim 15
Dependent Claim
74 words
A wireless location system (WLS) for locating a mobile transmitter that transmits narrowband signals spanning a predefined wideband of frequencies, wherein the wideband is greater than the narrowband, comprising: three geographically separated receivers for receiving narrowband signals; bandwidth synthesis means to make the mobile transmitter transmit at a plurality of narrowbands within the wideband; means for resolving integer cycle ambiguity in phase relationships; and TDOA means for determining the location of the mobile transmitter.
Claim 16
Dependent Claim
74 words
A wireless location system (WLS) for locating a mobile transmitter that transmits narrowband signals spanning a predefined wideband of frequencies, wherein the wideband is greater than the narrowband, comprising: three geographically separated receivers for receiving narrowband signals; bandwidth synthesis means to make the mobile transmitter transmit at a plurality of narrowbands within the wideband; means for resolving integer cycle ambiguity in phase relationships; and TDOA means for determining the location of the mobile transmitter.
Claim 17
Dependent Claim
42 words
An WLS as recited in claim 13, wherein the bandwidth synthesis means includes coupling from the WLS to a mobile switching center (MTSO or MSC) to make the mobile transmitter switch from one narrowband frequency range to a second narrowband frequency range.
Claim 18
Dependent Claim
33 words
An WLS as recited in claim 14, wherein the WLS can predefine which narrowband frequencies are used by the mobile transmitter, and the MSC reports to the WLS which narrowbands have been used.
Claim 19
Dependent Claim
25 words
An WLS as recited in claim 13, wherein the WLS includes means for calibration of the transmitter so that the TDOA processing is doubly differenced.
Claim 20
Dependent Claim
20 words
An WLS as recited in claim 13, wherein the bandwidth synthesis means includes means for determining wideband phase vs. frequency.
Claim 21
Dependent Claim
53 words
An WLS as recited in claim 13, wherein the means for resolving integer cycle ambiguity in phase relationships comprises means for solving the equation: φ=-fτ+n wherein φ is measured in cycles, f in Hz and τ in seconds, and n is an integer representing an intrinsic integer-cycle ambiguity of a doubly-differenced phase measurement.
Claim 22
Dependent Claim
19 words
A system as recited in claim 1, wherein the bandwidth of the individual narrowband signals is approximately 20 kHz.
Claim 23
Dependent Claim
20 words
A system as recited in claim 19, wherein the bandwidth of the wide band of frequencies is approximately 12.5 MHz.
Claim 24
Dependent Claim
27 words
A system as recited in claim 1, wherein the mobile transmitter uses an air interface protocol selected from the group consisting of AMPS, NAMPS, TDMA, and GSM.
Claim 25
Dependent Claim
19 words
A method as recited in claim 7, wherein the bandwidth of the individual narrowband signals is approximately 20 kHz.
Claim 26
Dependent Claim
20 words
A method as recited in claim 22, wherein the bandwidth of the wide band of frequencies is approximately 12.5 MHz.
Claim 27
Dependent Claim
27 words
A method as recited in claim 7, wherein the mobile transmitter uses an air interface protocol selected from the group consisting of AMPS, NAMPS, TDMA, and GSM.
Claim 28
Dependent Claim
19 words
A system as recited in claim 13, wherein the bandwidth of the individual narrowband signals is approximately 20 kHz.
Claim 29
Dependent Claim
20 words
A system as recited in claim 25, wherein the bandwidth of the wide band of frequencies is approximately 12.5 MHz.
Claim 30
Dependent Claim
27 words
A system as recited in claim 13, wherein the mobile transmitter uses an air interface protocol selected from the group consisting of AMPS, NAMPS, TDMA, and GSM.
References Cited (Backward Citations)
US4894662A
Cited
US5805200A
Cited
US5384574A
Cited
US5619212A
Cited
US4667203A
Cited
US4912475A
Cited
US5526357A
Cited
US5515419A
Cited
US5608410A
Cited
US5327144A
Cited
US5515062A
Cited
US5890068A
Cited
US5786790A
Cited
US5920278A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-07-18 | 2004-01-17 | 2004-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-07-18 | 2008-01-17 | 2008-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-07-18 | 2012-01-17 | 2012-07-18 | $7700.00 | Window Closed / Lapsed |