Relative Motion Between Two Earth Satellites

Design and analyze relative motion trajectories between two Earth satellites in circular orbits. Graphically display the orbital motion.

This submission is a MATLAB script named grmotion that can be used to design and analyze relative motion trajectories between two Earth satellites in circular orbits. The algorithms implemented in this script are based on the CW-equationsdescribed in the classic paper, “Terminal Guidance System for Satellite Rendezvous”, by W. H. Clohessy and R. S. Wiltshire, Journal of the Aerospace Sciences, Vol. 27, 1960.

In the following discussion the passive satellite is called the target and the active or maneuvering satellite is called the chaser. The state vector of the chaser satellite is defined with respect to a local vertical-local horizontal (LVLH) coordinate system centered at the target satellite.

This MATLAB script calculates and graphically displays the relative Keplerian motion between two satellites in circular Earth orbits. The software provides the following user options;

• user input of initial conditions
• calculate and display a synchronous orbit
• calculate and display a two impulse rendezvous orbit

The grmotion MATLAB script displays two-dimensional relative motion in the x-y plane.