| 摘要 |
An optical tracking system for aircraft and the like which measures positional variations of a portion of a laser transmitter pulse train or beam returned from a tracked object to derive error signals for energizing the tracking servo mechanism. In particular, the system detects such beam position change by measuring variations in energy received by a quadrant-segmented photo sensor relative to the sensor axis of symmetry. Compensation for scintillation (variation with time of the spatial intensity distribution) of the return beam due to change in the index of refraction of the atmosphere is achieved, in accordance with the invention, by focusing the return beam to a small diameter and passing it through a diffusing medium such as opal glass or a fiber optic bundle. The energy in the output beam from this medium is homogeneous and substantially invariant with time so that tracking error due to scintillation is eliminated.
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