Least-squares collocation - Physical Geodesy - page 370

ξ, η by (8-136).
3. Computation of the gravity anomalies ∆ g , also referred to the earth's
surface according to (8-128).
4. The topographic-isostatic reduction of ξ, η, ∆ g by (8-154) and (8-101)
gives values ξ c ,η c , ∆ g c which continue to refer to the surface point P .
5. The application of collocation to ξ c ,η c , ∆ g gives height anomalies ζ c
and cogeoid heights N c , by simply varying the elevation parameter ( h
and zero, respectively) in the collocation program (see Sunkel 1983).
6. By applying the indirect effect (10-2) and (8-153), we get actual height
anomalies ζ and geoidal heights N .