航空重力测量水平加速度改正的小波预处理

摘要

根据航空重力测量中水平加速度改正的频谱特性和小波变换频带划分规则,导出了水平加速度改正的小波预滤波尺度.以实测数据为例,基于信号小波变换尺度间的相关性,分别利用Haar小波、db4小波、db6小波和sym6小波对其进行小波预滤波处理,并与目前常用的FIR低通预滤波处理结果进行比对,结果表明:小波预滤波处理水平加速度改正的精度较FIR低通预滤波处理得到的精度高,并且用db系列小波进行预处理得到的结果精度更加均匀,据此提出对水平加速度改正预处理时应选用db系列小波或者支集较长的sym8小波.%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 isrnproposed that the Daubechies wavelets or the sym8 wavelet with much longer branch are more useful in the pre-pro-rncessing of the horizontal acceleration correction.