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.

Date Published: 9 November 2010
PDF: 7 pages
Proc. SPIE 7849, Optical Design and Testing IV, 784924 (9 November 2010); doi: 10.1117/12.870124

Published in SPIE Proceedings Vol. 7849:
Optical Design and Testing IV
Yongtian Wang; Julie Bentley; Chunlei Du; Kimio Tatsuno; Hendrik P. Urbach, Editor(s)