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Title: Light beam range finder

Abstract

A "laser tape measure" for measuring distance which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays. The transmit timing signal causes the transmitter to transmit the sequence of electromagnetic pulses at a pulse repetition rate, and the received timing signal sweeps over the range of delays in a sweep cycle such that reflections are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents received reflections in equivalent time. The receiver according to one aspect ofmore » the invention includes an avalanche photodiode and a sampling gate coupled to the photodiode which is responsive to the received timing signal. The transmitter includes a laser diode which supplies a sequence of visible electromagnetic pulses. A bright spot projected on to the target clearly indicates the point that is being measured, and the user can read the range to that point with precision of better than 0.1%.« less

Inventors:
 [1]
  1. Livermore, CA
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
871635
Patent Number(s):
US 5767953
Assignee:
Regents of University of California (Oakland, CA)
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
light; beam; range; finder; laser; tape; measure; measuring; distance; transmitter; diode; transmits; sequence; electromagnetic; pulses; response; transmit; timing; signal; receiver; samples; reflections; field; visible; controlled; receive; generates; sample; indicates; causing; circuit; supplies; causes; reflection; time; transmission; sampling; sweeps; delays; pulse; repetition; rate; received; sweep; cycle; sampled; represents; equivalent; according; aspect; avalanche; photodiode; gate; coupled; responsive; bright; spot; projected; target; measured; user; precision; signal causes; sampling gate; receive timing; sample signal; pulse repetition; electromagnetic pulses; equivalent time; repetition rate; timing signal; light beam; laser diode; timing circuit; transmit timing; receiver sweeps; signal sweeps; sweep cycle; receiver samples; range finder; controlled timing; circuit supplies; magnetic pulse; signal represents; electromagnetic pulse; measuring distance; /356/

Citation Formats

McEwan, Thomas E. Light beam range finder. United States: N. p., 1998. Web.
McEwan, Thomas E. Light beam range finder. United States.
McEwan, Thomas E. Thu . "Light beam range finder". United States. https://www.osti.gov/servlets/purl/871635.
@article{osti_871635,
title = {Light beam range finder},
author = {McEwan, Thomas E},
abstractNote = {A "laser tape measure" for measuring distance which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays. The transmit timing signal causes the transmitter to transmit the sequence of electromagnetic pulses at a pulse repetition rate, and the received timing signal sweeps over the range of delays in a sweep cycle such that reflections are sampled at the pulse repetition rate and with different delays in the range of delays, such that the sample signal represents received reflections in equivalent time. The receiver according to one aspect of the invention includes an avalanche photodiode and a sampling gate coupled to the photodiode which is responsive to the received timing signal. The transmitter includes a laser diode which supplies a sequence of visible electromagnetic pulses. A bright spot projected on to the target clearly indicates the point that is being measured, and the user can read the range to that point with precision of better than 0.1%.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {1}
}

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