US3738749A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rangefinders
Assignee: BAC AND BRITISH AEROSPACE
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Filing: 1971-10-12
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Granted: 1973-06-12
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Expires: 1991-10-12
Abstract
Abstract In a rangefinder (for example a laser rangefinder) emitting a pulse of electromagnetic energy, a pulse generator steps a counter to generate a progressively increasing signal following the emission of a pulse for a period corresponding to the delay before reception of a reflected pulse at the maximum range of interest. When a reflected signal is received the count at that instant is stored but subsequent reflections during the same period cause the stored value to be erased and replaced by the subsequent count. At the end of the said period the last stored value is transferred to a display unit. In this way, echoes from partially reflecting media between the emitter and a target are ignored.
Inventors
- 👤 F Everest
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:05
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/10; G01S13/14; G01S13/16; G01S17/00; G01S17/02; G01S17/06; G01S17/08; G01S17/10; G01S17/14; G01S7/00; G01S7/02; G01S7/28; G01S7/285; G01S7/292; G01S7/2921; G01S7/48; G01S7/483; G01S7/486; G01S7/4865; G01S7/487; G01S7/4873
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
168 words
A rangefinder comprising an emitter for emitting a pulse of electromagnetic energy, a detector for detecting the receipt of electromagnetic energy due to the reflection of the emitted pulse and generating a corresponding electric signal, means generating a progressively increasing electric signal for a period corresponding to a predetermined maximum range, storage means responsive to each reflection-representing signal from the detector during the said period for storing a value corresponding to the magnitude of the progressively increasing signal at thE instant of receipt of each reflection of an emitted pulse, a range indicator for displaying a stored value, and inhibiting means responsive to the detector output and operative in response to a received reflection to prevent the application to the range indicator of stored values corresponding to previously received echoes, and means for transferring to the range indicator at the end of the said period the stored value corresponding to the last received echo, whereby echoes from partially reflecting media between the emitter and the target are ignored.
Claim 2
Dependent Claim
168 words
A rangefinder comprising an emitter for emitting a pulse of electromagnetic energy, a detector for detecting the receipt of electromagnetic energy due to the reflection of the emitted pulse and generating a corresponding electric signal, means generating a progressively increasing electric signal for a period corresponding to a predetermined maximum range, storage means responsive to each reflection-representing signal from the detector during the said period for storing a value corresponding to the magnitude of the progressively increasing signal at thE instant of receipt of each reflection of an emitted pulse, a range indicator for displaying a stored value, and inhibiting means responsive to the detector output and operative in response to a received reflection to prevent the application to the range indicator of stored values corresponding to previously received echoes, and means for transferring to the range indicator at the end of the said period the stored value corresponding to the last received echo, whereby echoes from partially reflecting media between the emitter and the target are ignored.
Claim 3
Dependent Claim
141 words
A rangefinder comprising a laser for emitting a pulse of light, a detector for detecting the receipt of reflected laser light and generating a corresponding electric signal, a counter, a pulse generator providing periodic signals to drive the counter for a period corresponding to a predetermined maximum range, storage means, and means responsive to each reflection-representing signal from the detector during the said period for transferring to the storage means a value corresponding to the count existing in the counter at the instant of receipt of the reflected laser light, each transfer to the storage means erasing any earlier stored value, a range indicator for displaying a stored value, and means for transferring to the range indicator the stored value at the end of the said period, whereby reflections from partially reflecting media between the laser and the target are ignored.
Claim 4
Dependent Claim
141 words
A rangefinder comprising a laser for emitting a pulse of light, a detector for detecting the receipt of reflected laser light and generating a corresponding electric signal, a counter, a pulse generator providing periodic signals to drive the counter for a period corresponding to a predetermined maximum range, storage means, and means responsive to each reflection-representing signal from the detector during the said period for transferring to the storage means a value corresponding to the count existing in the counter at the instant of receipt of the reflected laser light, each transfer to the storage means erasing any earlier stored value, a range indicator for displaying a stored value, and means for transferring to the range indicator the stored value at the end of the said period, whereby reflections from partially reflecting media between the laser and the target are ignored.
Claim 5
Dependent Claim
40 words
A rangefinder in accordance with claim 2, in which the means for transferring the stored value comprises a second store and means for transferring the contents of the first store to the second store each time the counter is full.
Claim 6
Dependent Claim
20 words
A rangefinder in accordance with claim 2, including means for resetting the counter each time a light pulse is emitted.
Claim 7
Dependent Claim
30 words
A rangefinder in accordance with claim 1, in which the means generating a progressively increasing electric signal comprises a pulse generator and a counter receiving pulses from the pulse generator.
References Cited (Backward Citations)
US3409368A
Cited
US3315258A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |