Self-calibrating precision timing circuit and method for a laser range finder
AssigneeLaser Technology, Inc.
InventorJeremy G. Dunne
Life of this patent
Estimating the term…
Abstract
A highly precise range measurement instrument is made possible through the use of a novel and efficient precision timing circuit which makes use of the instrument's internal central processing unit crystal oscillator. A multi-point calibration function includes the determination of a "zero" value and a "cal" value through the addition of a known calibrated pulse width thereby providing the origin and scale for determining distance with the constant linear discharge of capacitor.
Claims19
A portable, hand held laser range finding apparatus comprising:
- a laser transmit section for generating a number of laser pulses for transmission toward a target;
- a laser receive section for receiving reflected laser pulses from said target;
- a central processor section coupled to said transmit and receive sections for determining a range to said target from the flight time between transmission and reception of each of said laser pulses and averaging a plurality of said flight times to determine a precision indication for said range to said target;
- and
- a display device connected to said processor section for displaying said range and said precision.
An apparatus for determining a range to a target based upon a flight time of a laser pulse toward said target, said apparatus comprising:
- means for transmitting said light pulse toward said target;
- means for detecting a reflected light pulse from said target and producing a signal proportional to the magnitude of said reflected pulse;
- means for comparing said reflection signal to said transmitted pulse to generate a target quality signal;
- and
- display means connected to said comparing means for displaying said target quality signal.
A laser range finder apparatus for determining a range to a target based upon a flight time of a pulse toward said target, said apparatus comprising:
- a laser transmit section for generating a number of laser pulses for transmission to a target;
- a laser receive section for receiving reflected laser pulses from said target;
- a precision timing section coupled to said laser transmit section and said laser receive section for determining a flight time of said laser pulses to said target and said reflected laser pulses from said target;
- a central processor section coupled to said precision timing section for determining a range to said target derived from said flight time of said laser pulses to said target and said flight time of said reflected laser pulses from said target;
- and
- a user selectable target acquisition mode switch coupled to said processor for selecting between at least a high sensitivity mode and a low sensitivity receiver mode of operation.
A laser range finder including an internal power supply unit for providing electrical power thereto comprising:
- a laser transmit section for generating a number of laser pulses for transmission to a target;
- a laser receive section for receiving reflected laser pulses from said target comprising a low pass filter network connected through a receive diode to a transimpedance amplifier and a precision comparator;
- a precision timing section coupled to said laser transmit section and said laser receive section for determining a flight time of said laser pulses and said reflected laser pulses;
- a central processor section coupled to said precision timing section for determining a range to said target derived from said flight time of said laser pulses and said flight time of said reflected laser pulses;
- a noise threshold section coupled to said laser receive section and responsive to said central processor section for determining a desired signal to noise ratio for said reflected laser pulses and providing a series of possible return pulse values to said central processor;
- and
- a display coupled to said central processor section for visually displaying said range to said target.
Dependencies are inferred from the claim text.