Kepler's Equation is a deceptively simple equation that relates an orbit's Mean Anomaly (M) with its Eccentric Anomaly (E):

M(t) = E(t) - esinE(t)

where: M(t) = The Mean Anomaly at time t;
            E(t) = The Eccentric Anomaly (E) at time t; and
                e = The satellite orbit's Eccentricity.

Kepler's Equation is transcendental and therefore cannot be analytically solved for E(t). Instead, computers can be used to find the best value of E(t) that satisfies the equation for the known values of M(t) and e.

Once E(t) is determined, the True Anomaly, n(t), can be determined.