The forward modelling of the gravity field

Abstract

The chapter has the purpose of presenting all the main characters of the book and some tools to handle them, and to understand their mathematical properties. We start with the gravitation law in Sect. 1.2, we clarify what is a gravitation field, in particular for an extended body, and we prove that this is a conservative or potential field (Sect. 1.3), i.e., the vector field of gravitational accelerations can be expressed as the gradient of a potential. Switching from an inertial system to one attached to the body of the earth, a proof mass rigidly attached to it will experience the centrifugal acceleration which is also a field that can be expressed as the gradient of a potential. By adding gravitational and centrifugal acceleration vectors, or their potentials (Sect. 1.3), we define the gravity field, which is the object of our study.