Precision laser surveying instrument using atmospheric turbulence compensation by determining the absolute displacement between two laser beam components

Patent · 01 January 1993

OSTI ID:868883

Veligdan, James T ^[1]

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1. Manorville, NY

Atmospheric effects on sighting measurements are compensated for by adjusting any sighting measurements using a correction factor that does not depend on atmospheric state conditions such as temperature, pressure, density or turbulence. The correction factor is accurately determined using a precisely measured physical separation between two color components of a light beam (or beams) that has been generated using either a two-color laser or two lasers that project different colored beams. The physical separation is precisely measured by fixing the position of a short beam pulse and measuring the physical separation between the two fixed-in-position components of the beam. This precisely measured physical separation is then used in a relationship that includes the indexes of refraction for each of the two colors of the laser beam in the atmosphere through which the beam is projected, thereby to determine the absolute displacement of one wavelength component of the laser beam from a straight line of sight for that projected component of the beam. This absolute displacement is useful to correct optical measurements, such as those developed in surveying measurements that are made in a test area that includes the same dispersion effects of the atmosphere on the optical measurements. The means and method of the invention are suitable for use with either single-ended systems or a double-ended systems.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY
• Assignee: Associated Universities, Inc. (Washington, DC)
• Patent Number(s): US 5233176
• OSTI ID: 868883
• Country of Publication: United States
• Language: English

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