Coordinates and Satellite Orbits

2013/3/6Jyh-Ching Juang, EE, NCKUKeplerian Orbital ParametersThe orbital elements can be categorized into two groups:One corresponds to the ellipse on the orbital plane and anotherdetermines the orientation of the orbital plane.The first three elements specify the size and shape of the orbit andthe time of latest perigee passage.The last three provides information on the coordinatetransformation.The six Keplerian orbital parameters area (semimajor axis of orbital ellipse): half length of the orbital ellipse.e (orbital eccentricity of ellipse): the apogee radius minus theperigee radius divided by their sum. e specifies the elongation ofthe orbital conic section.t 0 (latest epoch of perigee passage): the time at which the satellitepasses its perigee. This element can sometimes by equivalentlycharacterized by the mean anomaly M or the true anomaly . (argument of perigee): the angle between the ascending nodeand the perigee of the orbit measured in the orbital plane. Theargument is positive with increasing mean anomaly.i (inclination of orbital plane): the angle between the equatorialplane of the central body (Earth) and the satellite's orbital plane. (right ascension of the ascending node): the ascending nodalcrossing point measured in the equatorial plane from the vernalequinox to the nodal crossing point.23Jyh-Ching Juang, EE, NCKUKeplerian Orbital ParametersZEquatorial planeperigeegeocenterVernal equinox iAscending nodeGreenwich2412