Spectral Analysis of Nonstationary Spacecraft Vibration Data
MEASUREMENT ANALYSIS CORP LOS ANGELES CA
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This document is concerned with practical procedures for describing and analyzing the frequency composition of spacecraft launch vibration data. Since such data are generally nonstationary, conventional analysis techniques based upon time averaging individual sample records of data can produce misleading results. To help clarify the basic problems, the concept of stationary is reviewed, and theoretical methods for describing the frequency composition of nonstationary data are summarized. Both ensemble averaging and time averaging procedures are discussed with emphasis on the various errors associated with each approach. Experimental studies of actual spacecraft launch vibration data are then pursued to seek out typical or common trends which can be exploited to improve practical time averaging analysis procedures. Based upon the experimental studies as well as theoretical ideas, a specific procedure is recommended for the spectral analysis of nonstationary spacecraft vibration data, based upon time averaging short selected sample records of data.
- Unmanned Spacecraft