Patent ID: 7664578

Claim:
A method for establishing an initial inclination and right ascension of the ascending node (RAAN) of the orbits of each satellite of a constellation of Earth orbiting satellites in such a way that, over a specified operational life of the constellation, the associated inclination and RAAN values for each satellite can be allowed to drift in response to perturbative gravitational accelerations acting on the satellites while maintaining a required minimum line of sight elevation angle (MLOSEA) between a selected geographical area of the surface of the Earth and at least one satellite of the constellation and using a minimal amount of satellite propellant to effect out-of-plane control of the satellites, the method comprising: providing an initial value of the inclination and RAAN of each of the orbits of each of the satellites adapted to effect maintenance of the required MLOSEA; computing the resultant MLOSEA to the selected geographical area over the specified operational life of the constellation using the initial values of the inclinations and RAANs provided; varying the provided initial values of the inclination and RAAN of the orbit of a first one of the satellites by selected amounts in such a way as to obtain a MLOSEA greater than the required MLOSEA; re-computing the MLOSEA over the specified operational lifetime of the constellation using the varied initial inclination and RAAN values of the first satellite and the initial values provided of the inclination and RAAN of the other satellites; reiterating the preceding steps until the MLOSEA to the selected geographical area either meets the required MLOSEA or cannot be further increased; and, repeating the preceding steps for each of the orbits of the other satellites of the constellation.