Quasicircular ground tracks for geosynchronous earth satellites

A set of sufficient conditions on the Keplerian elements of a geosynchronous (24 h) earth satellite to produce a near-circular ground track on the rotating planet is derived. Once the required semimajor axis of the orbit and argument of perigee are found, a simple relationship between the eccentricity and the inclination of the orbital plane to the equatorial plane is obtained. The equation of the ground track is obtained. An analysis of the deviations of the ground tracks from circles is made using the root mean square error, the mean absolute error, and the area between the ground track and a circle. It was found that the first two tend to zero faster than does the quasi-radius of the ground track (the inclination), while the area tends to zero faster than the square of quasi-radius. Since the number of positions for satellites in geosynchronous orbit is limited, placing them in orbits that produce near-circular ground tracks centered over the equator can greatly increase the capacity.