Coverage Area Determination considering an Oblate Earth

The codes compute the boundary of the area covered from a satellite assuming a conical field-of-view and an oblate ellipsoid of rotation.

This set of codes introduces a new analytical method for the determination of the coverage area modeling the Earth as an oblate ellipsoid of rotation. Starting from the knowledge of the satellite’s position vector and the direction of the navigation antenna line of sight, the surface generated by the intersection of the oblate ellipsoid and the assumed conical field of view is decomposed in many ellipses, obtained by cutting the Earth’s surface with every plane containing the navigation antenna line of sight. The geometrical parameters of each ellipse can be derived analytically together with the points of intersection of the conical field of view with the ellipse itself by assuming a proper value of the half-aperture angle or the minimum elevation angle from which the satellite can be considered visible from the Earth’s surface. The method can be applied for different types of pointing (geocentric, geodetic, and generic) according to the mission requirements.

In the new release, there is an introduction of a new geometrical condition to assign the name P1 to the forward point and P2 to the backward point which is important for the second part of the algorithm. Moreover, the semi-major axis and semi-minor axis of the oblate ellipsoid have been put as input for the function to increase its generality.