Average rating
Cast your vote
You can rate an item by clicking the amount of stars they wish to award to this item.
When enough users have cast their vote on this item, the average rating will also be shown.
Star rating
Your vote was cast
Thank you for your feedback
Thank you for your feedback
Author
Tokuhiro, AtusiDate
1967
Metadata
Show full item recordAbstract
In make use of the Tokyo Surface Ship Gravity Meter (T.S.S.G.〕the recorded data are the period of the vibrating string affected by the frequency modulation according to the variation of the vertical acceleration of the moving vessel. As the inevitable consequence of the use of the digital procedure in the measurement device, given data are the sampled mean period over successive small time intervals. Therefore, data being suffered from the disturbing acceleration, there exist two main problems in the data processing ; one is how to evaluate the shift of the value of the vertical acceleration arised from the non-linear relation between the vertical acceleration and the period in the sampled data, and the other is the digital filtering by running of the suitable weighted mean. In this paper these problems are treated as follows: 1〕 Sampled mean periods Ti are converted into the vertical acceleration by the formula (5). 2) The integral term in the formula (5) can be evaluated by the polynomial appoximation of the period,using the preceding and following data at the considering datum. The formulae (9) and (13) represent the results of the integral in the cases of polynomials of 2nd and 4th degree, respectively. 3) Digital filtering are carried out by the formula (19) with the weighting coefficients wi (TABLE 1). It is shown that the resultant values of gravity approximated by the 4th degree polynomial are still small, but the higher degree approximation would complicate the numerical data handling. In the practical data processing, the adoption of an empirical magnifying constant to the polynomial approximation is appropriate and sufficient.Journal
Report of Hydrographic and Oceanographic ResearchesIssue/Article Nr
2Page Range
pp.1-12Resource/Dataset Location
https://www1.kaiho.mlit.go.jp/GIJUTSUKOKUSAI/KENKYU/report/rhr02/rhr02-01.pdf