A final upgrade to the Sparrow was the AIM-7P, which replaced the M's guidance system with an improved model that allowed mid-course upgrades to be sent from the launching platform via new rear-mounted antennas. For air-to-air use this allowed the missile to be "lofted" above the target and then be directed down towards it as it approached; this gives the missile greater range as it spends more time in thinner high-altitude air. In naval use, this meant it could also be directly guided against small surface targets that would otherwise not show up well on radar, allowing the ship's more powerful search radars to provide guidance until the missile approached the target and the reflected signal grew stronger. This also gave the Sea Sparrow a very useful secondary anti-shipping role that allows it to attack smaller boats.