航空重力测量数据的小波阈值滤波
Filtering of the Airborne Gravity Data by Wavelet Thresholding
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摘要: 基于航空重力测量实测数据,详细探讨了不同小波、阈值确定和施加方式及小波分解层次对滤波效果的影响。实验结果表明,db8、db10和coif5较适合于航空重力测量应用,小波的分解层次一般应取7层或8层,且不同的分解层次应当采用不同的恰当阈值,此时的滤波结果与地面参考值的比较精度为3~5×10-5ms-2,与采用截止频率为0.005 Hz的巴特沃什低通滤波器的滤波结果相当。Abstract: The principle of the wavelet threshold filtering is introduced briefly.Based on the airborne gravity real data,the effectiveness of using wavelet thresholding in filtering airborne gravity disturbance is checked.Different wavelet,different thresholding techniques and different decomposition level are tested.Results show that the db8,db10 and coif5 are the three wavelets suit for airborne gravimetry.If the highest decomposition level of the wavelets is seven or eight and in each level a different but suitable threshold is used,the accuracy of 3~5×10-5ms-2 can be reached in comparison to the ground reference.This accuracy is almost same as the approximation introduced by the Butterworth lowpass filter with 0.005 Hz cutoff frequency.
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