US4881809A
Expired / Lapsed
US
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Method and device for measuring distance optically
Assignee: Societe des Telephones Ericsson SA
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Filing: 1987-07-14
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Granted: 1989-11-21
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Expires: 2007-07-14
Abstract
Abstract For optical measurement of a distance between a hunter and a target, for instance between satellites, back-reflecting means are provided on the target. The hunter carries a source of substantially monochromatic light pulses and a solid state detector having a matrix of sensors. The matrix is read-out by transferring the contents of the sensors line per line or point per point at a predetermined frequency to an output memory. A time base triggers one pulse at a predetermined time selected for causing return of an echo from the target during read-out. The distance is derived from a determination of that line or that point which receives the echo, for two different transfer frequencies.
Inventors
- 👤 Bomer Thierry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:48
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/02; G01S17/06; G01S17/42
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
127 words
Optical process for measurement of a distance between a hunter and a target, comprising the steps of: (a) sending substantially monochromatic light pulses from the hunter toward the target; (b) collecting light echoed by the target on a matrix detector having photosensitive sites distributed in lines and columns with line-by-line transfer read-out (c) carrying out said transfer read-out in the direction of the columns at a first predetermined frequency during the time of flight between sending and return of the reflected echo from said target; (d) repeating the sequence of steps (a), (b) and (c) with another predetermined transfer frequency, different from the first frequency; and (e) deriving the distance from the distance between lines of the matrix having received the echo for the two different frequencies.
Claim 2
Dependent Claim
127 words
Optical process for measurement of a distance between a hunter and a target, comprising the steps of: (a) sending substantially monochromatic light pulses from the hunter toward the target; (b) collecting light echoed by the target on a matrix detector having photosensitive sites distributed in lines and columns with line-by-line transfer read-out (c) carrying out said transfer read-out in the direction of the columns at a first predetermined frequency during the time of flight between sending and return of the reflected echo from said target; (d) repeating the sequence of steps (a), (b) and (c) with another predetermined transfer frequency, different from the first frequency; and (e) deriving the distance from the distance between lines of the matrix having received the echo for the two different frequencies.
Claim 3
Independent Claim
166 words
A device for the optical measurement of a distance between a hunter and a target, comprising back reflecting means on the target and, on the hunter: a source of substantially monochromatic light pulses; a solid state detector having a matrix of sensors distributed into lines and columns; optical means for forming an image of light echoed by said reflecting means as a spot on one of said sensors; means for reading out said matrix of sensors by transferring the output of said sensors line per line or point per point in the direction of said columns, at a predetermined frequency to a detector output means; timing means for triggering one said light pulse at a predetermined time selected with respect to the beginning of said transfer for causing return of an echo from said target during transfer by the read-out means; and computing means for deriving said distance from an identification of those lines or those points which received echos associated with two different transfer frequencies.
Claim 4
Independent Claim
166 words
A device for the optical measurement of a distance between a hunter and a target, comprising back reflecting means on the target and, on the hunter: a source of substantially monochromatic light pulses; a solid state detector having a matrix of sensors distributed into lines and columns; optical means for forming an image of light echoed by said reflecting means as a spot on one of said sensors; means for reading out said matrix of sensors by transferring the output of said sensors line per line or point per point in the direction of said columns, at a predetermined frequency to a detector output means; timing means for triggering one said light pulse at a predetermined time selected with respect to the beginning of said transfer for causing return of an echo from said target during transfer by the read-out means; and computing means for deriving said distance from an identification of those lines or those points which received echos associated with two different transfer frequencies.
Claim 5
Dependent Claim
31 words
Device according to claim 2, wherein said computing means are arranged for subtracting the brightnesses of two mutually adjacent points of a same column for suppressing the effect of permanent lighting.
Claim 6
Dependent Claim
52 words
Device according to claim 2, further comprising means for adjusting the time period between the light pulse and the beginning of the transfer as a function of the back and forth time separating said light pulse and the echo at a value selected for the echo to be received during the transfer.
Claim 7
Dependent Claim
88 words
Device according to claim 2, wherein said detector consists of a CCD detector comprising an image zone consisting of a first matrix network of light responsive sensors distributed into said lines and columns and a memory zone which also consists of a second matrix network identical to the first, said read-out means being arranged for line-by-line transfer of the content of the image zone into the memory zone and from the memory zone into an output register from which the pixels of a same line are read-out sequentially.
Claim 8
Dependent Claim
25 words
Device according to claim 5, wherein said source consists of a laser diode which delivers the light pulses along an axis of said optical means.
Claim 9
Dependent Claim
88 words
Device according to claim 4, wherein said detector consists of a CCD detector comprising an image zone consisting of a first matrix network of light responsive sensors distributed into said lines and columns and a memory zone which also consists of a second matrix network identical to the first, said read-out means being arranged for line-by-line transfer of the content of the image zone into the memory zone and from the memory zone into an output register from which the pixels of a same line are read-out sequentially.
Claim 10
Dependent Claim
39 words
Process according to claim 1, wherein each of the lines has one photosensitive site only whereby the matrix detector has a single column, wherein said light pulseechoed by the target is focussed on the single column of photosensitive sites.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-20 | 1993-05-22 | 1993-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-20 | 1997-05-22 | 1997-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-20 | 2001-05-22 | 2001-11-21 | $7700.00 | Window Closed / Lapsed |