US4380807A
Expired / Lapsed
US
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Echo recognition system
Assignee: Polaroid Corp
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Filing: 1981-05-26
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Granted: 1983-04-19
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Expires: 2001-05-26
Abstract
Abstract An echo-type range finding system is rendered unresponsive to spurious signals and electronic noise, and has its object distance determining accuracy improved by rejecting signals that do not persist for a predetermined period of time.
Inventors
- 👤 John M. Reynard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:29
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/52; G01S7/523; G01S7/526; G01S7/527
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
136 words
A method of detecting a previously transmitted signal of energy returning from a selected target in the presence of energy signals from the source of other than the target, comprising the steps of: continuously sampling said returning target signal for a number of consecutive time intervals that are of very short time duration relative to the total time duration of said target signal; establishing that the sampled target signal magnitude increases between consecutive sampling intervals; establishing that the rate of increase of target signal magnitude between consecutive sampling intervals is greater than or equal to a predetermined rate of increase; and establishing that said signal magnitude increase and said rate of signal magnitude increase between consecutive sampling intervals is continuous for at least a predetermined portion of the total time duration of said returning target signal.
Claim 2
Independent Claim
136 words
A method of detecting a previously transmitted signal of energy returning from a selected target in the presence of energy signals from the source of other than the target, comprising the steps of: continuously sampling said returning target signal for a number of consecutive time intervals that are of very short time duration relative to the total time duration of said target signal; establishing that the sampled target signal magnitude increases between consecutive sampling intervals; establishing that the rate of increase of target signal magnitude between consecutive sampling intervals is greater than or equal to a predetermined rate of increase; and establishing that said signal magnitude increase and said rate of signal magnitude increase between consecutive sampling intervals is continuous for at least a predetermined portion of the total time duration of said returning target signal.
Claim 3
Dependent Claim
100 words
In a ranging system having means for transmitting a burst of energy toward a selected target and for then receiving energy so as to detect an echo from said target, the improvement wherein said transmitting and receiving means includes: means for providing a sum signal by summing a received signal over a number of consecutive sampling intervals of very short duration relative to the anticipated duration of an echo from a typical target; and means for identifying an echo as received from said selected target only when said sum signal progressively increases during each consecutive interval over a predetermined time.
Claim 4
Dependent Claim
100 words
In a ranging system having means for transmitting a burst of energy toward a selected target and for then receiving energy so as to detect an echo from said target, the improvement wherein said transmitting and receiving means includes: means for providing a sum signal by summing a received signal over a number of consecutive sampling intervals of very short duration relative to the anticipated duration of an echo from a typical target; and means for identifying an echo as received from said selected target only when said sum signal progressively increases during each consecutive interval over a predetermined time.
Claim 5
Dependent Claim
45 words
The improvement of claim 2 wherein said means for identifying an echo includes means for identifying an echo as received from said target only when said sum signal progressively increases over said consecutive intervals at a rate equal or greater than a predetermined positive rate.
Claim 6
Dependent Claim
44 words
The improvement of claim 3 wherein said means for identifying an echo includes returning said sum signal to an initial value each time said sum signal fails to increase or the rate of increase, during any given interval, is less than said predetermined rate.
Claim 7
Dependent Claim
51 words
The improvement of claims 2, 3 or 4 including means for determining the time of occurrence of the leading edge of the actual echo by subtracting said predetermined time from the time at which the echo is identified by said means for identifying an echo as received from said selected target.
Claim 8
Dependent Claim
85 words
A ranging method for detecting an echo from a selected target in the presence of spurious signals, said method comprising the steps of: summing the energy of received signals over a number of consecutive sampling intervals of short duration relative to the anticipated duration of an echo from a typical target so as to provide a sum signal; and establishing that an echo is received from said selected target only when said sum signal increases during each consecutive interval over a predetermined period of time.
Claim 9
Dependent Claim
85 words
A ranging method for detecting an echo from a selected target in the presence of spurious signals, said method comprising the steps of: summing the energy of received signals over a number of consecutive sampling intervals of short duration relative to the anticipated duration of an echo from a typical target so as to provide a sum signal; and establishing that an echo is received from said selected target only when said sum signal increases during each consecutive interval over a predetermined period of time.
Claim 10
Dependent Claim
54 words
The method of claim 6 wherein said establishing step includes comparing the rate of increase of said sum signal with a predetermined positive rate and identifying an echo as received from said target only when the rate of increase of said sum signal in each of said consecutive intervals exceeds said predetermined positive rate.
Claim 11
Dependent Claim
34 words
The method of claim 7 including the step of returning said sum signal to an initial value each time the rate of increase during any given interval is less than said predetermined positive rate.
Claim 12
Dependent Claim
22 words
The method of claim 7 wherein said predetermined period of time is a substantial portion of the anticipated duration of the echo.
Claim 13
Dependent Claim
42 words
The method of claim 6 or 7 wherein the leading edge of the actual echo is identified as occurring at a time equal to said predetermined time prior to the point of establishing that an echo is received from said selected target.
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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) | 1986-04-18 | 1986-10-18 | 1987-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-04-18 | 1990-10-18 | 1991-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-04-18 | 1994-10-18 | 1995-04-19 | $7700.00 | Window Closed / Lapsed |