With OTHR there is a large degree on uncertainty in the return. It will tell you that there is something in an area say 20x20 miles, moving in roughly Y direction, at about X speed. Jindalee can tell you approximately what size, and whether it is in the air or on the ground, but there is a minimum size it just won't pick up. For example, it can pick up Indonesian fishing boats, even in pretty rough seas, and they are about the size of a military aircraft. Light civilian aircraft are right at the bottom end of its capabilities, but are doable under most conditions. Thus, even if you know something is out there, you either have to be a ble to paint it with something capable of more precise resolution, or send somebody out to Mark One it.