An airborne sensor is developed for remote sensing on an aerial vehicle (UV). The sensor is an optical
payload for an eletro-optical/infrared (EO/IR) dual band camera that combines visible and IR imaging
capabilities in a compact and lightweight package. It adopts a Ritchey-Chrétien telescope for the common
front end optics with several relay optics that divide and deliver EO and IR bands to a charge-coupleddevice
(CCD) and an IR detector, respectively. The EO/IR camera for dual bands is mounted on a two-axis
gimbal that provides stabilized imaging and precision pointing in both the along and cross-track directions.
We first investigate the mechanical deformations, displacements and stress of the EO/IR camera through
finite element analysis (FEA) for five cases: three gravitational effects and two thermal conditions. For
investigating gravitational effects, one gravitational acceleration (1 g) is given along each of the +x, +y
and +z directions. The two thermal conditions are the overall temperature change to 30℃ from 20℃ and
the temperature gradient across the primary mirror pupil from -5℃ to +5℃. Optical performance,
represented by the modulation transfer function (MTF), is then predicted by integrating the FEA results
into optics design/analysis software. This analysis shows the IR channel can sustain imaging performance
as good as designed, i.e., MTF 38% at 13 line-pairs-per-mm (lpm), with refocus capability. Similarly, the
EO channel can keep the designed performance (MTF 73% at 27.3 lpm) except in the case of the overall
temperature change, in which the EO channel experiences slight performance degradation (MTF 16% drop)
for 20℃ overall temperate change.
© 2011 Optical Society of Korea
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