US5596330A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Differential ranging for a frequency-hopped remote position determination system
Assignee: Nexus Telecommunication Systems Ltd
•
Filing: 1995-02-16
•
Granted: 1997-01-21
•
Expires: 2015-02-16
Abstract
Abstract A differential ranging location system is described which uses a modified time-of-arrival technique to determine the location of a frequency hopped spread spectrum radio signal. The transmitter simultaneously transmits two radio frequency carriers having different frequencies such that a phase difference is observed between the two carriers at a distance from the transmitter. The phase difference is proportional to the range from the transmitter that the carrier signals are observed. The two carrier signals from the single transmitter are received by at least three and in special cases four base stations which calculate the differential time of arrival based on the phase differences of the received carriers. The calculated phase differences are then sent to a central location which locates the position of the transmitter based upon a planer hyperbolic location algorithm. Since a large number of narrow band frequencies across a wide spectrum are used in a frequency hopping transmission protocol, the accuracy in determining the phase differences between the two carriers is increased and the immunity to interference is also increased.
Inventors
- 👤 Hanoch Yokev
- 👤 Shimon Peleg
- 👤 Yehouda Meiman
- 👤 Boaz Porat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:47
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/02; G01S3/023; G01S1/00; G01S1/02; G01S1/022; G01S1/026; G01S11/00; G01S11/02; G01S3/04; G01S3/043; G01S3/10; G01S5/00; G01S5/0009; G01S5/02; G01S5/0205; G01S5/021; G01S5/04; G01S5/14; H; H04; H04B; H04B1/00; H04B1/69; H04B1/713; H04B1/7156; H04B7/00; H04B7/24; H04B7/26; H04B7/2662; H04B7/2671; H04B7/2678; H04B7/2681; H04B7/2687; H04B7/2693; H04W; H04W64/00; H04W88/00; H04W88/02; H04W88/022
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
246 words
A differential ranging mobile transmitter location system, comprising: a mobile transmitter having a unique identifier, and having a transmitter for simultaneously sending a first frequency-hopped spread spectrum carrier signal and a second frequency-hopped spread spectrum carrier signal, at least one of which containing the unique identifier, the first frequency-hopped spread spectrum carrier having a different frequency than the second frequency-hopped spread spectrum carrier signal; a first base station having an antenna operable for receiving the first and second frequency-hopped spread spectrum carrier signals and capable of determining a first time of arrival of the frequency-hopped spread spectrum carrier signals; a second base station also having an antenna operable for receiving the first and second frequency-hopped spread spectrum carrier signals and capable of determining a second time of arrival of the frequency-hopped spread spectrum carrier signals; and a central station connected to the first base station and the second base station, and operable for: 1.) receiving the first time of arrival of the first and second frequency-hopped spread spectrum carrier signals from the first base station; 2.) receiving the second time of arrival of the first and second frequency-hopped spread spectrum carrier signals from the second base station; 3.) generating a first hyperbolic plot based on the differential time of arrival of the first and second frequency-hopped spread spectrum carrier signals at the first and second base stations; and 4.) using a third information source to determine the location of the transmitter along the first hyperboplic plot.
Claim 2
Dependent Claim
246 words
A differential ranging mobile transmitter location system, comprising: a mobile transmitter having a unique identifier, and having a transmitter for simultaneously sending a first frequency-hopped spread spectrum carrier signal and a second frequency-hopped spread spectrum carrier signal, at least one of which containing the unique identifier, the first frequency-hopped spread spectrum carrier having a different frequency than the second frequency-hopped spread spectrum carrier signal; a first base station having an antenna operable for receiving the first and second frequency-hopped spread spectrum carrier signals and capable of determining a first time of arrival of the frequency-hopped spread spectrum carrier signals; a second base station also having an antenna operable for receiving the first and second frequency-hopped spread spectrum carrier signals and capable of determining a second time of arrival of the frequency-hopped spread spectrum carrier signals; and a central station connected to the first base station and the second base station, and operable for: 1.) receiving the first time of arrival of the first and second frequency-hopped spread spectrum carrier signals from the first base station; 2.) receiving the second time of arrival of the first and second frequency-hopped spread spectrum carrier signals from the second base station; 3.) generating a first hyperbolic plot based on the differential time of arrival of the first and second frequency-hopped spread spectrum carrier signals at the first and second base stations; and 4.) using a third information source to determine the location of the transmitter along the first hyperboplic plot.
Claim 3
Dependent Claim
42 words
The mobile location system according to claim 1 wherein a reference station operates periodically to transmit a reference first and second frequency-hopped spread spectrum carrier signal from a known location to calibrate the first and second base stations and the central station.
Claim 4
Dependent Claim
29 words
The mobile location system according to claim 1 wherein the first base station and the second base station both include atomic clocks to synchronize the time of arrival calculations.
Claim 5
Dependent Claim
39 words
The mobile location system according to claim 1 wherein the third information source is a geographic map of the area around the base stations which provides information on the probable location of the transmitter along the first hyperbolic plot.
Claim 6
Dependent Claim
57 words
The mobile location system according to claim 1 wherein the third information source is a third base station which calculates the time of arrival of the first and second frequency-hopped spread spectrum carrier signals and wherein the base station generates a second hyperbolic plot to intersect the first hyperbolic plot to identify the location of the transmitter.
Claim 7
Dependent Claim
84 words
The mobile location system according to claim 1 wherein the transmitter transmits a plurality of hops each having a different first and second frequency-hopped spread spectrum carrier signals and the time of arrival is determined by a.) calculating the phase difference between the first and second frequency-hopped spread spectrum carrier signals for each of the plurality of hops to produce a plurality of phase differentials; and b.) performing an Inverse Fourier Transform on the plurality of phase differentials to produces a time of arrival.
Claim 8
Independent Claim
90 words
A method of locating a mobile transmitter location, comprising the steps of: receiving at a first base station a dual radio carrier having two frequencies and calculating therefrom a first time of arrival of the dual carrier; receiving at a second base station a dual radio carrier having two frequencies and calculating therefrom a second time of arrival of the dual carrier; comparing the first time of arrival with the second time of arrival; and determining the location of the origin of the dual radio carrier by hyperbolic intersection location.
Claim 9
Independent Claim
90 words
A method of locating a mobile transmitter location, comprising the steps of: receiving at a first base station a dual radio carrier having two frequencies and calculating therefrom a first time of arrival of the dual carrier; receiving at a second base station a dual radio carrier having two frequencies and calculating therefrom a second time of arrival of the dual carrier; comparing the first time of arrival with the second time of arrival; and determining the location of the origin of the dual radio carrier by hyperbolic intersection location.
References Cited (Backward Citations)
US2437695A
Cited
US3445847A
Cited
US3747104A
Cited
US3864681A
Cited
US3886554A
Cited
US3972042A
Cited
US4188629A
Cited
US4114155A
Cited
US4217586A
Cited
US4229620A
Cited
US4369426A
Cited
US4449127A
Cited
US5191342A
Cited
WO1983000563A1
Cited
JPS5828675A
Cited
US4589078A
Cited
US4596988A
Cited
US4698781A
Cited
US4494119A
Cited
US4665404A
Cited
US4665379A
Cited
US4905271A
Cited
US4791572A
Cited
US4728959A
Cited
US4740792A
Cited
WO1988001750A1
Cited
US4742357A
Cited
US5099245A
Cited
US4891650A
Cited
US5055851A
Cited
WO1989012835A1
Cited
US5081667A
Cited
US5003317A
Cited
US5021794A
Cited
US5150310A
Cited
FR2667949A3
Cited
US5216429A
Cited
US5365516A
Cited
US5166694A
Cited
US5365451A
Cited
US5372411A
Cited
US5218367A
Cited
US5396540A
Cited
EP0583523A2
Cited
US5379047A
Cited
US5311197A
Cited
US5317323A
Cited
US5327144A
Cited
US5500648A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-01-21 | 2000-07-22 | 2001-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-01-21 | 2004-07-22 | 2005-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-01-21 | 2008-07-22 | 2009-01-21 | $7700.00 | Window Closed / Lapsed |