A Comparison of Methods for Microvibration Analysis in Frequency- and Time-Domain
- Paper number
IAC-18,C2,3,13,x42952
- Author
Mr. Torben Runte, Germany, OHB System AG-Bremen
- Coauthor
Mr. Alexander Kuisl, Germany, OHB System AG - Oberpfaffenhofen
- Coauthor
Dr. Bernard Lübke-Ossenbeck, Germany, OHB System AG-Bremen
- Year
2018
- Abstract
The term Microvibration or Optical/Line-of-Sight Jitter refers to mechanical oscillations beyond the bandwidth of the Attitude Control System (ACS), which occur during the satellite in-orbit operations and thus affect, for example, its pointing performances. The topic is of particular interest for space missions with optical payloads and their growing performance demands. Microvibration is a systems engineering topic, involving subjects such as mechanical design & analysis, mechanism engineering, payload design, operations and the ACS. The accurate prediction of microvibration disturbances on the mission performances is thus a complex multidisciplinary field aiming to design and implement a robust – but not too conservative – system. Such analyses, in particular at system level, are at the limit of numerically feasible, as they involve high-frequency structural dynamics and high-performance noise source disturbance models. While typical microvibration performance requirements are formulated in the time-domain (e.g. Pointing errors on confidence intervals), microvibration analyses are often carried out in the frequency-domain. It has been observed in ongoing programs that the accuracy of such predictions suffers from conservatism introduced in the analysis process, in particular in the conversion from the frequency-domain to the time-domain. In this paper, the traditional method of microvibration simulation in the frequency-domain is compared to simulations in the time-domain. The aim of this activity is to derive analysis tools, which allow accurate predictions of microvibration in a numerically efficient manner. The applied methodology for simulations in the time-domain is explained. In addition, guidelines are derived in order to achieve more realistic analyses in the frequency-domain.
- Abstract document
- Manuscript document
(absent)