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Title: Method and apparatus for coherent burst ranging

Abstract

A high resolution ranging method is described utilizing a novel modulated waveform, hereafter referred to as coherent burst modulation. In the coherent burst method, high frequency modulation of an acoustic or electromagnetic transmitter, such as a laser, is performed at a modulation frequency. This modulation frequency is transmitted quasi-continuously in the form of interrupted bursts of radiation. Energy from the transmitter is directed onto a target, interacts with the target, and the returning energy is collected. The encoded burst pattern contained in the collected return signal is detected coherently by a receiver that is tuned so as to be principally sensitive to the modulation frequency. The receiver signal is processed to determine target range using both time-of-flight of the burst envelope and phase shift of the high frequency modulation. This approach effectively decouples the maximum unambiguous range and range resolution relationship of earlier methods, thereby allowing high precision ranging to be conducted at arbitrarily long distances using at least one burst of encoded energy. The use of a receiver tuned to the high frequency modulation contained within the coherent burst vastly improves both sensitivity in the detection of the target return signal and rejection of background interferences, such as ambientmore » acoustic or electromagnetic noise. Simultaneous transmission at several energies (or wavelengths) is possible by encoding each energy with a separate modulation frequency or pattern; electronic demodulation at the receiver allows the return pattern for each energy to be monitored independently. Radial velocity of a target can also be determined by monitoring change in phase shift of the return signal as a function of time.« less

Inventors:
 [1];  [2]
  1. (138 Bay Path Dr., Oak Ridge, TN 37830)
  2. (8514 Carl Valentine, Knoxville, TN 37931)
Publication Date:
Research Org.:
LOCKHEED MARTIN ENRGY SYST INC
OSTI Identifier:
871514
Patent Number(s):
US 5745437
Assignee:
Wachter, Eric A. (138 Bay Path Dr., Oak Ridge, TN 37830);Fisher, Walter G. (8514 Carl Valentine, Knoxville, TN 37931) ORNL
DOE Contract Number:
AC05-84OR21400
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
method; apparatus; coherent; burst; ranging; resolution; described; utilizing; novel; modulated; waveform; hereafter; referred; modulation; frequency; acoustic; electromagnetic; transmitter; laser; performed; transmitted; quasi-continuously; form; interrupted; bursts; radiation; energy; directed; target; interacts; returning; collected; encoded; pattern; contained; return; signal; detected; coherently; receiver; tuned; principally; sensitive; processed; determine; range; time-of-flight; envelope; phase; shift; approach; effectively; decouples; maximum; unambiguous; relationship; earlier; methods; allowing; precision; conducted; arbitrarily; distances; vastly; improves; sensitivity; detection; rejection; background; interferences; ambient; noise; simultaneous; transmission; energies; wavelengths; encoding; separate; electronic; demodulation; allows; monitored; independently; radial; velocity; determined; monitoring; change; function; time; return signal; modulation frequency; earlier methods; phase shift; frequency modulation; receiver signal; range resolution; simultaneous transmission; coherent burst; resolution ranging; magnetic noise; vastly improves; burst envelope; background interference; described utilizing; /367/342/

Citation Formats

Wachter, Eric A., and Fisher, Walter G. Method and apparatus for coherent burst ranging. United States: N. p., 1998. Web.
Wachter, Eric A., & Fisher, Walter G. Method and apparatus for coherent burst ranging. United States.
Wachter, Eric A., and Fisher, Walter G. Thu . "Method and apparatus for coherent burst ranging". United States. doi:. https://www.osti.gov/servlets/purl/871514.
@article{osti_871514,
title = {Method and apparatus for coherent burst ranging},
author = {Wachter, Eric A. and Fisher, Walter G.},
abstractNote = {A high resolution ranging method is described utilizing a novel modulated waveform, hereafter referred to as coherent burst modulation. In the coherent burst method, high frequency modulation of an acoustic or electromagnetic transmitter, such as a laser, is performed at a modulation frequency. This modulation frequency is transmitted quasi-continuously in the form of interrupted bursts of radiation. Energy from the transmitter is directed onto a target, interacts with the target, and the returning energy is collected. The encoded burst pattern contained in the collected return signal is detected coherently by a receiver that is tuned so as to be principally sensitive to the modulation frequency. The receiver signal is processed to determine target range using both time-of-flight of the burst envelope and phase shift of the high frequency modulation. This approach effectively decouples the maximum unambiguous range and range resolution relationship of earlier methods, thereby allowing high precision ranging to be conducted at arbitrarily long distances using at least one burst of encoded energy. The use of a receiver tuned to the high frequency modulation contained within the coherent burst vastly improves both sensitivity in the detection of the target return signal and rejection of background interferences, such as ambient acoustic or electromagnetic noise. Simultaneous transmission at several energies (or wavelengths) is possible by encoding each energy with a separate modulation frequency or pattern; electronic demodulation at the receiver allows the return pattern for each energy to be monitored independently. Radial velocity of a target can also be determined by monitoring change in phase shift of the return signal as a function of time.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 1998},
month = {Thu Jan 01 00:00:00 EST 1998}
}

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