Resonant cavity enhanced laser frequency-swept carrier ranging method for noncooperative targets

Conventional frequency-sweep interferometry is unreliable for noncooperative or long-distance targets owing to scattering on the target surface. Hence, this paper proposes a laser frequency-swept carrier (LFSC) ranging method based on resonant cavity enhancement for long-distance noncooperative target measurements and weak-signal detection. Experimental verification revealed that for a target comprising an oxidized black aluminum plate at a distance of 16 m, the standard deviation of 10 measurements was less than 70 μm, measurement accuracy exceeded 27 μm, and system ranging resolution exceeded 0.13 mm when the target feedback light was very weak. This method is useful for measurements of noncooperative targets, e.g., large-scale component assembly, industrial measurement, and biomedical testing.