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Joint Stars

The Joint Surveillance and Target Attack Radar System (JSTARS) is a joint development project of the US Air Force and Army which provides an airborne, stand-off range, surveillance and target acquisition radar and command and control centre.

In September 1996, JSTARS was approved for full rate production for 14 aircraft. Eight have been delivered. The 93rd Air Control Wing operates the JSTARS aircraft at Robins Air Force Base in Georgia.

JSTARS provides ground situation information through communication via secure data links with air force command posts, army mobile ground stations and centres of military analysis far from the point of conflict. JSTARS provides a picture of the ground situation equivalent to that of the air situation provided by AWACS. JSTARS is capable of determining the direction, speed and patterns of military activity of ground vehicles and

JSTARS was first deployed in Operation Desert Storm in 1991 when still in development, and has since been deployed to support peacekeeping operations in Bosnia-Herzegovina and during the Kosovo crisis.

On a standard mission the aircraft has a crew of 21 with three flight crew and 19 systems operators. On a long endurance mission the aircraft has a crew of 34, with 6 flight crew and 28 system operators.


The Boeing 707-300 series aircraft is the JSTARS airframe. The aircraft are remanufactured at Northrop Grumman in Lake Charles, Louisiana, then transferred to the Battle Management Systems Division in Melbourne, Florida where the electronics are installed and tested.

The propulsion system of the JSTARS aircraft consists of four Pratt and Whitney JT3D-3B turbojet engines, each providing 18,000 pounds of thrust. The aircraft has a flight endurance of 11 hours or 20 hours with in-flight refuelling.


The radar system is produced by Northrop Grumman Norden Systems. A 24 ft antenna is installed on the underside of the aircraft, which is mechanically swivelled and pointed to scan in elevation, and scans electronically in azimuth to determine the location and heading of moving targets.

The main operating modes of the radar are wide area surveillance, fixed target indication, synthetic aperture radar,
moving target indicator and target classification modes.

The US Air Force has awarded Northrop Grumman a contract to develop the next generation JSTARS as part of the Radar Technology Insertion Program (RTIP). The new much more powerful radar will be an electronically scanned 2-D X-band active aperture radar which will have a helicopter detection mode and inverse synthetic aperture (ISAR) imaging capability, as well as MTI (moving target indicator) mode, allowing realtime imaging
of moving objects.


JSTARS aircraft have 17 operations consoles and one navigation/self-defense console. A console operator can carry out sector search focusing on smaller sectors and automatically track selected targets. Fixed high value targets are detected through synthetic aperture radar (SAR).

Signal processing techniques are implemented through four high-speed data processors, each capable of performing more than 600 million operations per second. Processed information is distributed via high-speed computer circuitry to tactical operators throughout the aircraft.

In 1997, the US Air Force awarded Northrop Grumman two contracts for a computer replacement program to take advantage of the latest commercial off-the-shelf technology (COTS). The program will integrate new Compaq AlphaServer GS-320 central computers that will be significantly faster than the original system. The programmable signal processors will be replaced and a high-capacity switch and fibre-optic cable will replace the copper-wired workstation network. The Computer Replacement Plan (CRP) has completed EMD testing and is expected to enter
production in 2001.


JSTARS has secure voice and datalinks to the Army's ground command and communications stations and to the Air Force command centres. Voice communications systems include 12 encrypted UHF radios, two encrypted HF radios, three VHF encrypted radios with provision for Single Channel Ground and Airborne Radio System (SINCGARS) and multiple intercom nets.

The digital datalinks include a satellite communications link (SATCOM), a surveillance and control datalink (SCDL) for transmission to mobile ground stations, and Joint Tactical Information Distribution System (JTIDS). The JTIDS provides tactical air navigation (TACAN) operation and Tactical Data Information Link-J (TADIL-J) generation and processing. The Cubic Defense Systems SCDL is a time division multiple access datalink incorporating flexible frequency management. The system employs wideband frequency hopping, coding and data diversity to achieve robustness against hostile jamming. Uplink transmissions use a modulation technique to determine the path delay between the ground system module and the E-8 aircraft.

The E-8C aircraft is the airborne element of the US JSTARS battlefieldmanagement and peacekeeping system
JSTARS aircraft layout schematic
Operators workstations are Raytheon-militarized versions of the DEC Alpha system and utilise Windows to make their tasks easier and faster
At these consoles operators track ground targets using the many Moving Target Indicator and Synthetic Aperture Radar capabilities of JSTARS
This handheld terminal unit was used to send targeting data to the head-up display of an F-16
The phased array antenna is tilted mechanically about its longitudinal axis to scan in elevation, but relies on electronics for azimuth
Joint STARS provides seamless connectivity between air and land component forces
The Boeing 707 is capable of carrying the 8m antenna and not encounter problems with radar coverage or aerodynamic performance
JSTARS has a flight endurance of 11 hours or 20 hours with in-flight refuelling