Patent USH1044H successfully refreshed from Google Patents.
USH1044H
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Method and apparatus for precision ranging using stable clocks
Assignee: United States Department of the Navy
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Filing: 1990-12-28
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Granted: 1992-04-07
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Expires: 2010-12-28
Abstract
Abstract Methods for accurately measuring the range between two platforms with relative motion between them using a stable clock located on each platform. A series of pulses are sent from one platform to the other at times known to each platform by prearrangement, the arrival times measured, and statistical methods used to calculate a correction from the clocks to bring them into greater synchronization, thus allowing highly accurate determination of the range between the two platforms.
Inventors
- 👤 William M. Waters
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:57
CPC Classifications
G; G01; G01S; G01S11/00; G01S11/02; G01S11/08; G04; G04G; G04G7/00; G04G7/02
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
179 words
A method for synchronizing a first and a second clock, each said clock being associated with a respective one of a first and a second platform, said method comprising: sending N signals, numbered n=1, 2, . . ., N, from said first platform to said second platform; wherein for each nth one of said N signals, the expected arrival time of said nth one of said N signals at said second platform being known a priori: making an estimate τ n of the time of flight of said nth one from said first platform to said second platform; transmitting said nth one at time t n -τ n , t n being said expected arrival time for said nth one as measured by said first clock; and determining t' n , where t' n is the time of arrival of said nth one at said second platform as measured by said second clock; wherein said method further comprises: ##EQU5## either (a) resetting said second clock by a time Δ, or (b) resetting said first clock by a time -Δ.
Claim 2
Independent Claim
179 words
A method for synchronizing a first and a second clock, each said clock being associated with a respective one of a first and a second platform, said method comprising: sending N signals, numbered n=1, 2, . . ., N, from said first platform to said second platform; wherein for each nth one of said N signals, the expected arrival time of said nth one of said N signals at said second platform being known a priori: making an estimate τ n of the time of flight of said nth one from said first platform to said second platform; transmitting said nth one at time t n -τ n , t n being said expected arrival time for said nth one as measured by said first clock; and determining t' n , where t' n is the time of arrival of said nth one at said second platform as measured by said second clock; wherein said method further comprises: ##EQU5## either (a) resetting said second clock by a time Δ, or (b) resetting said first clock by a time -Δ.
Claim 3
Independent Claim
259 words
A method for determining the range between a first and a second platform having associated respective first and second clocks, said method for determining comprising: synchronizing said first and said second clocks, said synchronizing comprising: sending N signals, numbered n=1, 2, . . ., N, from said first platform to said second platform; wherein for each nth one of said N signals: making an estimate τ n of the time of flight of said nth one from said first platform to said second platform; transmitting said nth one at time t n -τ n , t n being the expected arrival time for said nth one as measured by said first clock; and determining t' n , where t' n is the actual time of arrival of said nth one at said second platform as measured by said second clock; wherein said synchronizing further comprises: ##EQU6## either (a) resetting said second clock by a time Δ, or (b) resetting said first clock by a time -Δ; wherein said method for determining said range further comprises: sending an additional signal from one of said first or said second platform to the other of said first or said second platforms at a preselected time known to each of said platforms a priori by prearrangement; using said clock associated with said other of said platforms to measure the arrival time of said additional signal at said other of said platforms; using the difference between said preselected time and said arrival time to determine said range between said first and said second platforms.
Claim 4
Independent Claim
259 words
A method for determining the range between a first and a second platform having associated respective first and second clocks, said method for determining comprising: synchronizing said first and said second clocks, said synchronizing comprising: sending N signals, numbered n=1, 2, . . ., N, from said first platform to said second platform; wherein for each nth one of said N signals: making an estimate τ n of the time of flight of said nth one from said first platform to said second platform; transmitting said nth one at time t n -τ n , t n being the expected arrival time for said nth one as measured by said first clock; and determining t' n , where t' n is the actual time of arrival of said nth one at said second platform as measured by said second clock; wherein said synchronizing further comprises: ##EQU6## either (a) resetting said second clock by a time Δ, or (b) resetting said first clock by a time -Δ; wherein said method for determining said range further comprises: sending an additional signal from one of said first or said second platform to the other of said first or said second platforms at a preselected time known to each of said platforms a priori by prearrangement; using said clock associated with said other of said platforms to measure the arrival time of said additional signal at said other of said platforms; using the difference between said preselected time and said arrival time to determine said range between said first and said second platforms.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-04-07 | 1995-10-07 | 1996-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-04-07 | 1999-10-07 | 2000-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-04-07 | 2003-10-07 | 2004-04-07 | $7700.00 | Window Closed / Lapsed |