Israel has tweaked (modified) the software in its two AWACS (Airborne Early Warning Aircraft) so the CAEW (Conformal Airborne Early Warning) radar system can spot small, low flying UAVs as well as manned aircraft.
These CAEW aircraft were developed in Israel and the first one entered service in 2008. This AWACS uses a long range business jet (the 40 ton Gulfstream G550) and Israeli made radar and electronics. The Israeli Air Force operates two CAEW AWACs and three similar ELINT (electronic intelligence) aircraft based on the slightly smaller G500 aircraft. The CAEW AWACS has also been sold to Italy, Singapore and the United States. Tweaks for improved performance or new capabilities (finding UAVs) are frequent for Israeli military systems because Israel is constantly under attacks (or threat of attack) and gear it makes for itself is constantly being used and improved. This is very attractive to many potential foreign buyers.
The CAEW AWACS carries a Phalcon conformal (it is built into the lower fuselage) phased array radar plus SIGINT equipment (to capture and analyze enemy electronic transmissions) and a communications system that can handle satellite signals as well as a wide array of other transmissions. There are six personnel on board to handle all this gear, plus the flight crew. The Gulfstream G550 used for this can stay in the air for nine hours per sortie and can fly at up to 13,200 meters (41,000 feet).
The G550 is a larger version of the Gulfstream G400, which the U.S. Army uses as the C-20H transport. The U.S. Coast Guard, Air Force, and Navy also use militarized Gulfstreams (usually as C-37Vs). The 30 meter (96 foot) long aircraft has two engines and was built for long flights (over 11,000 kilometers). Current Gulfstream G550s cost about $50 million each.
The Phalcon radar is, in some respects, superior to the one used in the American AWACS. For example, Phalcon uses a phased array radar (thousands of small radar transmitters are fitted underneath the aircraft). The phased array radar, in combination with the latest, most powerful computers and other antennas for picking up a variety of signals, enables Phalcon to be more aware of what electronic equipment (airborne or on the ground) is operating up to 400 kilometers away. The phased array radar allows positions of aircraft on operator screens to be updated every 2-4 seconds, rather than every 20-40 seconds as is the case on the United States AWACS (which uses a rotating radar in a radome atop the aircraft). The first Phalcon system was fitted on a Boeing 707, although somewhat limited versions could be put onto a C-130. On a larger aircraft you can have more computers, and other electronics, as well as more human operators. But the major advantage of the Phalcon is that it is a more modern design. The U.S. AWACS dates to the 1980s and has undergone upgrades to the original equipment. The Israeli air force first installed Phalcon radar systems in an old Boeing 707 but the G550 replaced it.