There is so much air activity over Iraq these days, as a U.S. led coalition increases its air attacks on ISIL (Islamic State in Iraq and the Levant) targets that the Iraqi ATC (air traffic control) system is overwhelmed. Using airborne radar systems like the AWACS is too expensive and the Americans asked their NATO allies for someone to supply a suitable ground based radar to fill in as a round-the-clock ground based AWACS. Denmark supplied one of their TPS77 radar systems.
TPS77 which are used for national air defense by the United States (and 26 other countries) can detect aircraft out to 450 kilometers, and up to 33 kilometers (100,000 feet) altitude. The North American system has 15 TPS77s in Alaska, 11 in Canada, and one each in Hawaii, Puerto Rico and Utah. The TPS77 phased array (AESA) radar panel can be set up anywhere and have the radar information, and the status of the radar, monitored elsewhere. The TPS77 operates, on average, about 11 weeks before needing the attention of any technicians. A fixed version of this radar, the FPS77 is cheaper but the mobile TPS77 can be moved using three tractor trailers. There are nearly 200 F/TPS77 radars in use in 27 countries. The Danish TPS77 has been operational since January 2016.
The E-3 AWACS costs about $40,000 per flight hour to operate. That’s over ten times the hourly cost to operate a TPS-77 system. Part of the cost problem is that most E-3s are decades old. The first E-3 prototypes were flying in the late 1970s and the E-3 entered service in 1982. Flying far enough inside friendly territory to avoid enemy anti-aircraft missiles, the AWACS radar has a radar range from between 200 km (for small aircraft or cruise missiles flying close to the ground) to 600 kilometers (for large aircraft flying at high altitude). The AWACS tracks several hundred friendly and enemy aircraft at once. The AWACS acts as an airborne command center for aircraft and friendly planes are kept out of each other's way. For example, there was not a single friendly air to air collision during the 1991 Gulf war or in any subsequent operations using the E-3. Enemy aircraft are spotted, identified, and friendly interceptors assigned to take care of the hostile planes using the E-3. One or more AWACS is used to control an air operation and each can stay up 11 hours at a time, or up to 22 hours with refueling and extra crew on board to man the equipment.