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As the improvement of imaging resolution of earth observation satellite, the optical axis disturbance
(referred as LOS jitter) introduced by satellite moving components, such as reaction wheel, CMG,
cryocooler etc., become one of the important factors that limits the imaging quality.
So far as we know, there are several methods to control the frequency and amplitude of LOS jitter,
such as satellite attitude control system (ACS), vibration isolator, image stabilization system etc. Each
method has its own application range: ACS can only response to low frequency disturbance to
about one tenth Hz, but it can deal with large amplitude disturbance; vibration isolator usually
attenuates LOS jitter amplitude in high frequency, but may magnify jitter in low frequency; image
stabilization can stabilize the LOS jitter in low-mid frequency, but limited to small amplitude. So it is
necessary to use several methods together to insure the imaging quality. Here comes the question,
how to design and allocate the system specification reasonably to satisfy the requirement of
imaging and to make it possible for these methods to realize.
This paper presents a new optimization method based on the frequency domain for the satellite
imaging chain related with optical axis jitter. First describe the performance of each link of the
imaging chain in the frequency domain, then through the calculation of image MTF using LOS jitter
PSD, build up the relation between the imaging quality and the frequency performance of mixed
links, then combine the frequency performance and the spectral decomposition method, the
relation between each link and system imaging quality can be built. Then Based on this method, the
requirement of imaging quality related to each link can be allocate and optimize quantitatively,
which is essential for the design of imaging chain related with optical axis jitter.
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