When infrared optical system works in a large temperature range, the thermal effect of optical lens and optical tube will
produce image plane shift and lead to imaging quality deterioration. In order to eliminate the thermal aberration, the
athermalization design principles of infrared optical system were introduced, and some commonly used methods of
thermal difference compensation were described. Proceeding from single lens, the thermal difference caused by
temperature changing was analyzed, and the relationship between temperature and focus shift was obtained. Considering
optical tube thermal expansion, a set of equations to estimate the thermal difference of lens group was given. Finally, an
infrared optical imaging system that can work under the temperature range of -40°C to 60°C was design according to
athermal technique, in which a new mechanical passive temperature compensation was proposed. Through simulation,
the athermalization design could make imaging plane shift the smallest. The simulation results coincided with the
theoretical formula, and the design had reference value in engineering.
It is essential to analyze the gimbal displacement errors for a seeker due to the importance for cueing of targets and
tracking for the final approach. Otherwise, for a seeker electro-driven with a concentric glass dome, the large errors will
decrease the picking, pointing, and tracking precision rooted from the displacement errors existing between the rotation
center of the optical system and the gimbal. And the gimbaled camera system displacement errors are never eliminated
but reduced due to the geometric errors consists of geometric tolerances of gimbal structure, manufacture, installation
and vibration coming from working environment.
In this paper, the gimbal displacement errors in an electro-optically stabilized platform resulting from geometric errors
and environment errors were analyzed and shown in detail. The mathematical modal of the gimbal displacement errors
created based on multi-body dynamics demonstrated the connection between the gimbal displacement errors and the
stabilized platform. Taking a visible light image seeker as a case, the diameter is 120mm, and the geometric tolerances
came from the values of primary design and the vibration data came from the environmental vibration test on the
pitch-yaw seeker, and at the same time, the errors resulting from installation were considered too. Based on calculating,
the maximum gimbal displacement error will reach to 0.2mm for pitching angle smaller than 40° and yawing angle
smaller than 60°. However, the critical parts have been found out according to the probability theory and the reliability
analysis successfully used in the paper, and finally, the maximum gimbal displacement error reduced to 0.1mm, which is
acceptable corresponding to the picking, pointing and tracking precision for an optical imaging seeker.
A review of high-speed flow pressure and aerodynamic heating effect on Supersonic missile's dome is given. The dome
should have excellent properties in optical, mechanical and chemical characteristics. A design of dome on supersonic
mode is described according to tactical guide line of a missile. The dome made of quartz which is about 8mm thick and
141mm in window diameter. To check up the reliability of the dome, a reasonable finite element model (FEM) of dome
is established, and a thermal-mechanical Analysis to the dome by finite element software NASTRAN has carried on,
through these can obtained the distribution of temperature field and stress field when the speed is 2.3Ma. The results
indicated that the stress was concentrated in the joint of the dome end and the Missile Section, and the maximum stress
was 16.4Mpa. The stress of other nodes was smaller than the allowable stress of quartz glass. Reference to the results of
the analysis, a lightweight revision to the dome structural dimension and a new method of dome fixing have put forward,
which can reduce the stress concentration.
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