Optical and Quantum Electronics

, Volume 13, Issue 1, pp 35–45 | Cite as

A CO2 laser rangefinder using heterodyne detection and chirp pulse compression

  • K. F. Hulme
  • B. S. Collins
  • G. D. Constant
  • J. T. Pinson
Papers

Abstract

The sensitivities of heterodyne and direct-detection systems at CO2 laser wavelengths are compared to illuminate the design principles involved. It is shown that destruction of the temporal coherence of scattered radiation is a significant effect when heterodyne systems are used on targets with internal motion. The complete system and the results obtained are then described. The compact optics head contains a waveguide laser, an acousto-optic modulator and SAW chirp devices; it has 45 mm diameter transmit and receive apertures. Whem many returns are integrated, ranges of several kilometres are obtained off natural targets with an accuracy of 10 m. From the Doppler shift off a moving target, radial velocity can be determined simultaneously with the range when an up-chirp/down-chirp technique is used; an accuracy of better than 1 m s−1 is demonstrated.

Keywords

Coherence Radial Velocity Design Principle Laser Wavelength Scattered Radiation 

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Copyright information

© Chapman and Hall Ltd 1981

Authors and Affiliations

  • K. F. Hulme
    • 1
  • B. S. Collins
    • 1
  • G. D. Constant
    • 1
  • J. T. Pinson
    • 1
  1. 1.Royal Signals and Radar EstablishmentMalvernEngland

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