The Calculation of High-Order Vertical Derivative in Gravity Field by Tikhonov Regularization Iterative Method

Table 2

Comparison of the three methods.

Method	Maximum (g.u./km^2)	Minimum (g.u./km^2)	Average value (g.u./km^2)	Root mean square error (g.u./km^2)
Theoretical value	55.00	−29.76	0.31
Conventional FFT	42.95	−20.31	0.29	4.50
ISVD	54.88	−30.82	0.04	1.62
Method in this paper	57.61	−31.77	0.33	1.29