Planning approach trajectories to enable late aborts for fixed-wing UAV recovery on ships

For a fixed-wing UAV performing an autonomous recovery in a ship-mounted arrest system, several events can make it preferrable to abort the landing, including issues with communication systems, navigation sensors, or wind gusts exceeding required limits, in order to retry when conditions improve. If the recovery involves impacting an arrest system, aborts cannot necessarily be performed arbitrarily late without a risk of colliding with other parts of the ship. Automatic aborts should therefore only be possible when a safe abort is feasible. We propose a concept where optimization is used to generate an approach trajectory which enables aborts as late as safely possible. The concept is demonstrated using a simple three dimensional UAV model, for several different scenarios. This is then compared to less complex approach plans. The implemented example demonstrates that optimization can be useful for planning approach trajectories and allow later aborts than the simple methods.