Optical turbulence measurement

A method comprising:

• receiving a first portion of a source beam by a first aperture of a first optics assembly as a first received beam;
• magnifying and directing the first received beam to a camera assembly for receipt by the camera assembly;
• receiving a second portion of the source beam by a second aperture of a second optics assembly as a second received beam;
• magnifying and directing the second received beam to the camera assembly for receipt by the camera assembly;
• receiving, by processing circuitry, a data representation of the first received beam and the second received beam from the camera assembly;
• determining, by the processing circuitry, a focal spot displacement variance based on motion of a first focal spot corresponding to the first received beam relative to a second focal spot corresponding to the second received beam;
• and
• measuring optical turbulence along a path of the source beam based on the focal spot displacement variance.

A system comprising:

• an optical turbulence measurement device comprising:
• a support structure;
• a camera assembly coupled to the support structure;
• a first optics assembly coupled to the support structure, the first optics assembly being configured to magnify and direct a first portion of a source beam received by a first aperture of the first optics assembly to the camera assembly to be received as a first received beam;
• a second optics assembly coupled to the support structure, the second optics assembly being configured to magnify and direct a second portion of the source beam received by a second aperture of the second optics assembly to the camera assembly to be received as a second received beam;
• an optical source coupled to the support structure and configured to generate an output beam;
• and
• processing circuitry;
• and
• a retroreflector located a retroreflector distance away from the optical source, the retroreflector configured to reflect the output beam to be received by the first aperture and the second aperture as the source beam;
• wherein the processing circuitry is configured to:
• receive a data representation of the first received beam and the second received beam from the camera assembly;
• determine, based on the data representation, a focal spot displacement variance based on motion of a first focal spot corresponding to the first received beam relative to a second focal spot corresponding to the second received beam;
• and
• measure optical turbulence along a path of the source beam based on the focal spot displacement variance and a path-weighting function that varies over the retroreflector distance.