From Killet Software:
SEVENPAR is a tool for the calculation of transformation parameters for the Spatial Helmert and Molodensky Transformation, which make possible precise coordinate transformations from one reference system into another. The determined transformation parameters can be entered directly into transformation software, example TRANSDAT Coordinate Transformations, or into the calculation software of GPS receivers to do coordinate transformations. The seven or three transformation parameters are computed with a set of individual identical points. Those are points with known coordinates in both reference systems (geodetic datum). Cartesian coordinates, geographical coordinates or UTM coordinates with or without ellipsoidal height using the ellipsoid dimensions. Identical measuring points of higher order can be usually inquired or referred by the official institutions for measurement. The necessary ellipsoid half-axes and flattening are available in the program for the selection from lists. The coordinates of the identical points are tested on outliers and deviations by different statistic procedures. The quality of the computed parameters is documented by a residual matrix and by the computation of the middle, maximum, and root mean square (RMS) deviations.