Maximum allowable low-frequency platform vibrations in high resolution satellite missions: challenges and look-up figures

Abstract

Performance of high resolution remote sensing payloads is often limited due to satellite platform vibrations. Effects of Linear and high frequency vibrations on the overall MTF are known exactly in closed form but the low frequency vibration effect is a random process and must be considered statistically. It should be considered in system level payload designing to know whether or not the overall MTF is limited by the vibration blur radius. Usually the vibration MTF budget is defined based on the mission requirements and the overall MTF limitations. With a good understanding of harmful vibration frequencies and amplitudes in the system preliminary design phase, their effects could be removed totally or partially. This procedure is cost effective and let designer to just eliminate the harmful vibrations and avoids over-designing. In this paper we have analyzed the effects of low-frequency platform vibrations on the payload’s modulation transfer function. We have used a statistical analysis to find the probability of imaging with a MTF greater or equal to a pre-defined budget for different missions. After some discussions on the worst and average cases, we have proposed some “look-up figures” which would help the remote sensing payload designers to avoid the vibration effects. Using these figures, designer can choose the electro-optical parameters in such a way, that vibration effects be less than its pre-defined budget. Furthermore, using the results, we can propose a damping profile based on which vibration frequencies and amplitudes must be eliminated to stabilize the payload system.