Patent ID: 7669803
Filing Date: 2010-03-02
Classification: B64G,H04B

Abstract:
1. A method for determining orbits for a plurality of spacecraft in a constellation, comprising: determining an approximately 24-hour orbit for each one of the plurality of spacecraft, the plurality of spacecraft including a first, second and third spacecraft, each of the plurality of spacecraft including a broadcast capability, wherein each of the orbits is a substantially teardrop-shaped or oval-shaped ground, and has an apogee longitude of approximately 90° west to approximately 100° west, wherein each of the orbits has a semi-major axis of approximately 42,164 kilometers, an argument of perigee ω of approximately 270°, an inclination i of approximately 40° to approximately 60°, and an eccentricity e of approximately 0.16 to approximately 0.4, and wherein the orbits of each of the plurality spacecraft are selected to bring each of said spacecraft to apogee at time increments of approximately eight hours; and optimizing one or more of the argument of perigee, the inclination, the eccentricity, and a longitude of an ascending node L for each of the orbits by minimizing a cost function selected from the group of wherein 90°−min[θ