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WAVELET PRE-PROCESSING FOR HORIZONTAL ACCELERATION OF AERIAL GRAVITY MEASUREMENT

According to the spectrum characteristic of the horizontal acceleration correction in the aerial gravity measurement and the partition rules of wavelet transformation frequency band,the wavelet pre-filter scale of the horizontal acceleration correction is deduced. On the basis of the correlation among the wavelet transform scales of the signal,as an example,some surveying data were pre-processed by Haar wavelet、db4 wavelet、db6 wavelet and sym6 wavelet,and the results are compared with the results from FIR low pass filter in common use.The comparison shows that the precision of the wavelet pre-filter is higher than the FIR low pass filter in the pre-processing of the horizontal acceleration correction and it is more symmetrical as pre-processed by db serial wavelets.Thus it is proposed that the Daubechies wavelets or the sym8 wavelet with much longer branch are more useful in the pre-processing of the horizontal acceleration correction.