Wrong equation in IERS Conventions computation of geopotential coefficient changes due to solid Earth pole tide
IERSConventions.java, both for
IERS_2010, there appears to be an error in the ratio used to compute the corrections to the geopotential coefficients due to the effect of the solid Earth pole tide.
The equations published in the IERS Technical Note No. 36 (IERS Conventions 2010) read:
∆C₂₁ = −1.333 × 10⁻⁹ (m₁ + 0.0115m₂) ∆S₂₁ = −1.333 × 10⁻⁹ (m₂ − 0.0115m₁)
which is the same that the comments in the file suggest. However, in both line 1281 and 1812, the ratio is implemented as 0.00115 (an additional 0). The comments in the
IERS_2003 section (see lines 1333~1358) indicate that there already was a sign issue that was corrected in the IERS 2010 Conventions, and in fact go on to demonstrate the origin of the error by estimating the ratio as:
Im(k₂)/Re(k₂) where k₂ is the complex number 0.3077 + 0.0036i, yielding ratio ≈ Im(k₂)/Re(k₂) ≈ 0.0115 (not 0.00115)
I believe this is an error in the implementation that is very easy to fix and should be corrected asap because it will lead to incorrect values of accelerations during propagations that include solid tide forces.