Aerial recovery of autonomous micro air vehicles (MAVs) presents many unique challenges due to the difference in size and speed of the recovery vehicle and MAV. This paper presents algorithms to enable an autonomous MAV to estimate the orbit of a recovery vehicle and track the orbit until the final docking phase. Several algorithms are presented, which are shown to be robust and computationally inexpensive. Methods for estimating ellipses that are rotated out of the x-y plane are developed and demonstrated through simulation. An algorithm to enable the MAV to track the recovery vehicle's orbit, based on the vector field approach, is also presented.