Reference systems

Abstract

Consider the basic observation equation which relates the range ϱ with the instantaneous position vector $\underline \varrho ^S$ of a satellite and the position vector of $\underline \varrho _R$ the observing site:

$$ \varrho = \left\| {\underline \varrho ^S - \underline \varrho _R } \right\| \cdot $$

((3.1))

In Eq. (3.1) both vectors must be expressed in a uniform coordinate system. The definition of a three-dimensional Cartesian system requires a convention for the orientation of the axes and for the position of the origin.