------------------
File mean-pole.tab
------------------
Author: christian.bizouard@obspm.fr
Updated: June 16 2016
The mean pole coordinates x and y are obtained by Gaussian mean of the IERS C01 pole
coordinates computed at 0.05 year interval from 1900. At date T, the mean values (xm, ym)
of the samples (x_i, y_i) at date T_i ( i=1,...,n) are given by
xm(T) = Sum w_i x_i / Sum w_i
ym(T) = Sum w_i y_i / Sum w_i
where the weights are determined by the Gaussian function
w_i = exp[-0.5* ((T(i)-T)/a)^2]
with a = 3.40 years.
This procedure is also a low pass frequency filter having the frequency transfer function
T(f) = exp[-2*pi^2 (a f)^2].
For a =3.4, we have:
T(f=1/25 cycle/year) = 70%
T(f=1/50 cycle/year) = 91%
T(f=1/100 cycle/year) = 98%
-----------------------
File mean-pole.tab.2015
-----------------------
Author: daniel.gambis@obspm.fr
Obtained by Filter CENSUS X11
http://www.census.gov/ts/papers/x11doc.pdf