Geometrical methods for formation flying design based on the analytical solution to Hill's equations have been previously developed and used to specify desired relative motions in near circular orbits. These approaches offer valuable insight into the relative motion and allow for the rapid design of satellite configurations to achieve mission specific requirements, such as vehicle separation at perigee or apogee, minimum separation, or a particular geometrical shape. A comparable set of geometrical relationships for formations in eccentric orbits, where Hill's equations are not valid, is presented. The use of these relationships to investigate formation designs and their evolution in time is demonstrated.
Nomenclature
A= amplitude parameter a = semimajor axis C = unit vector in cross-track directon E = eccentric anomaly e = eccentricity I = unit vector in in-track direction i = inclination M = mean anomaly n = mean motion P = magnitude of position error R = unit vector in radial direction r = magnitude of r r = Earth-centered-inertial (ECI) position vector S = sensitivity matrix T = transformation matrix from ECI coordinates to RIC coordinates t = time V = magnitude of velocity error v = ECI velocity vector W e = rotation rate of Earth, 7.2921158553 × 10 −5 rad/s x = radial position distance from origin of radial, in-track, cross-track (RIC) frame y = in-track position distance from origin of RIC frame z = cross-track position distance from origin of RIC frame α = generic orbital element, for example, a, e, i, , ω, or M 0 γ = phase angle in in-track/cross-track plane α = small perturbation in α θ = argument of latitude µ = gravitational parameter of Earth, 3.986004418 × 10 14 m 3 /s 2 ν = true anomaly ξ = cross-track angular separation ρ = distance between two points in RIC frame ϕ = in-track angular separation ψ = phase parameter = right ascension of ascending node ω = argument of perigee