16-04-2012, 03:21 PM
OPTOPHYSICAL MEASUREMENTS
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Measurements of the laser radar (ladar) characteristics of aircraft on unobstructed paths are important for verification
of experimental and theoretical methods and mathematical models for determining their optical signature and also for
assessing the capabilities of laser measurement systems [1]. However, in small-scale and field studies on unobstructed paths,
there are always complications connected with calibration (standardization against reference standards) and also reduction of
systematic and random errors and improvement of the reliability of the measurement results [2, 3]. Therefore unique results,
characterized by elevated accuracy and reliability, are important [3].
Below we consider methods and instrumentation enabling small-scale studies of the reflection characteristics of
objects on an unobstructed near-ground path and field measurements of the ladar characteristics of aircraft (in flight) using a
laser tracking system (LTS) for direct detection and a land-based Doppler coherent ladar (CLL).
Small-Scale Studies of the Ladar Characteristics of Objects on an Unobstructed Path Using a Land-Based
Laser Test Bench. The land-based laser test bench (LLTB), deployed as part of a multifunctional optical measurement system,
is designed for small-scale studies of the reflection characteristics of objects on an unobstructed near-ground path under
stationary conditions (Fig. 1). It includes:
1) a receiver/transmitter unit based on lasers and photodetectors for the visible and infrared ranges, which is mounted
on a massive optical table positioned on a base that is isolated from the building. In this case, guiding the laser beam and
the field of view of the photodetector to the object to be measured can be accomplished using a periscopic system, consisting
of a rigidly clamped lower mirror and a remote-controlled upper mirror with an external sputtered coating;
2) a mast-type lift-and-turn device positioned at a specified distance L from the receiver/transmitter unit, which
makes it possible to lift and rotate the objects under study;