Variable Scale Filter for Satellite Time-Variable Gravity Fields

The most common smoother for GRACE(-FO) time variable gravity field is Gaussian smoother. However, traditional Gaussian smoother does not consider the variance of noise in high and low latitudes, or the anisotropy of the noise.
In this context, we establish this software to numerically realize a new design of filter called variable-scale (VS)
filter, which can take both the variance and the anisotropy of noise into consideration.