The Tokyo Surface Ship Gravity Meter: Recent Developments for Solving Non-Linear Rectification Error and Phase Lag Problems.
WOODS HOLE OCEANOGRAPHIC INSTITUTION MASS
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The Tokyo Surface Ship Gravity Meter T.S.S.G. has been using the frequency of a single vibrating string to measure vertical acceleration. An important source of error caused by a non-linear relationship between the frequency of vibration and environmental acceleration, has been suspected since the T.S.S.G. was first used. A new data processor for the T.S.S.G. has been constructed which is based on a rapid reading of frequency of vibration by means of pulse train logic. Results from the new processor have been compared with the results from the conventional method of data processing, and the authors have confirmed an improved performance of the new processor. The problem of the phase lag of measurement which occurs when an analogue type low pass filter is used is discussed, and a method to remove the phase lag by use of a deconvolution filter is described. Modified author abstract