A new target-in-the-loop (TIL) atmospheric sensing concept for in-situ remote measurement of major atmospheric parameters is discussed. The proposed technique is based on utilization of integral relationships between complex amplitudes of the counter-propagating waves, whose values are preserved along the propagation path, for atmospheric turbulence characterization. We show that these relationships, referred to here as the remote sensing invariants, can be directly measured using a TIL sensor composed of a single-mode fiber-based optical transceiver and a remotely located small-size retro-reflector. The measured signals allow retrieval of key turbulence characteristics along the target line of sight, including refractive index structure parameter and scintillation index. The discussed concept allows practical development of a compact TIL atmospheric sensor that does not require installation of an additional transmitter/receiver device at the other end of the laser beam propagation path.
© 2014 Optical Society of AmericaPDF Article