改进小波阈值降噪法在航空扰动重力数据处理中的应用

Using Improved Wavelet Threshold Denoising Method to Deal with Airborne Disturbance Gravity Data

比较分析了各种小波阂值降噪方法的特点，利用改进小波阈值函数对航空扰动重力数据进行了降噪处理。实验结果表明，当小波分解到第9层时，db8、db9和sym7小波的降噪效果比较理想，3条重复测线扰动重力的平均内符合精度分别为1．05mGal、1．15mGal和1．13mGal，与利用截止频率为0．004Hz的巴特沃斯低通滤波器的处理结果相当；对于同一小波，调节因子取0～1间的任一值时，改进小波阈值函数结果的平均内符合精度均高于强制去噪法和软硬闯值去噪法；改进小波阈值函数的调节因子对去噪效果有影响，不同的小波的最优调节因子不尽全相同。

Based on the analysis of various wavelet threshold denoising methods, the improved wavelet threshold function is chosen to denoise the airborne disturbance gravity data. The experimental results show that when the wavelet is decomposed into ninth layers, the effect of noise reduction of db8, db9 and sym7 is ideal. The average inertial accuracy of disturbance gravity of three repeat-lines can reach 1.05mGal, 1.15mGal and 1.13mGal, respectively, which is comparable to the result of Butterworth low-pass filter with cut-off frequency of 0. 004Hz. For the same wavelet, when the adjustment factor takes any value between 0 and 1, the average inertial accuracy of disturbance gravity of repeat-lines by using improved wavelet threshold function is more accurate than the method of forced denoising and soft threshold denoising. The adjustment factor of improved wavelet threshold function affects the denoising effect, and the optimal value of the adjustment factor is various with wavelet.