Py6S: A Python interface to the 6S radiative transfer model

This paper focuses on studying long distance height datum transfer across seas by a method, using GPS/leveling and gravimetric geoid fitting with an additional parameter. The method combines earth gravitational model EGM2008 with ellipsoidal height derived from GPS, to determine the height datum difference between a mainland and an island. Fitting function is given as a polynomial surface. An iteration algorithm by using different regularization parameters is adopted to solve the ill-conditioned matrix in the normal equation. The precision of the additional parameter is estimated. The feasibility of the proposed method is validated by practical data of two bridge constructions. It can obtain the height datum parameter and quasi-geoid model successively. The objective of long distance height datum transfer is then achieved. Comparing the computed value with known value, the results show that the inconsistencies of the height datum difference are small. No matter how many the differences are, they can be computed precisely. Precision of the computed height datum can satisfy the engineering requirement of the height. Therefore it can be applied in practical engineering, or to validate the reliability of other methods for long distance leveling. This method is low cost, efficient and reliable, and can be generally used in geodesy.