Electronic Weapons: Sentinel Succeeds To Survive


August 1, 2013: Britain's RAF (Royal Air Force) recently revealed details of operations by one of its Sentinel R1 ASTOR (Airborne Stand-Off Radar) aircraft over Mali earlier this year. At the request of France, Britain sent a Sentinel aircraft to Mali in January, where it operated until May. During that time Sentinel flew 66 sorties (averaging about 11 hours each) and delivered over a hundred detailed reports to French commanders about activity on the ground.

This Sentinel mission to Mali almost didn’t happen. Two years ago, faced with major budget cuts over the next five years, the RAF selected the Sentinel aircraft for inactivation to save money. That was avoided only because many fervent RAF and army Sentinel fans called for this aircraft to remain in service. That was mainly because of how successful Sentinel has been in Afghanistan. Then Sentinel was sent to Libya and proved as useful there as it had been in Afghanistan. British officials recognized this and now plans to retire Sentinel only after 2015, when British ground troops are scheduled to be withdrawn from Afghanistan.

The RAF has been told they could more inexpensively replicate Sentinel functions in a UAV. But with all these cuts, the RAF does not see getting enough money to develop a UAV Sentinel replacement. It cost $1.5 billion to develop Sentinel and build five of them, and army commanders believe they would be invaluable in any future operations.

It was only five years ago, after a decade of development, that Sentinel aircraft were first sent into action in Afghanistan. Sentinel is similar to the three decade old U.S. E-8 JSTARS. But instead of mounting the radar and computers in a four engine jet transport (the 707), the British used a 44 ton Canadian Bombadier Global Express twin engine business jet. The highly automated Sentinel has two pilots and three people in the back running the surveillance equipment. Sentinel operates at about 15,000 meters (45-50,000 feet) and can track vehicles, or even people, on the ground up to 160 kilometers away. Large vehicles (like missile transporters/launchers) can be tracked at twice that range. Sorties in Afghanistan averaged about nine hours, although the aircraft is capable of staying in the air for 14 hours. The U.S. has been using its E-8 ground radar aircraft in Iraq and Afghanistan with great success and Sentinel had a similar experience.

Sentinel uses a U.S. made Raytheon ASARS-2 radar. This is a Synthetic Aperture Radar (SAR) system that can cover a large area or focus on a smaller area and even provide photo quality images. Sentinel also has a large array of electronic warfare equipment and counter-missile systems. But in Afghanistan it mainly uses its radar, and its satellite and ground communications links, to send images to the troops below, who can then run down known or suspected hostiles.

In Afghanistan Sentinel was also used for intelligence work (to determine normal traffic patterns in an area and to alert combat commanders when abnormal traffic shows up) and to track enemy vehicles. The Taliban typically move around in trucks and SUVs and sometimes on motorcycles. All can be tracked by Sentinel, in any weather. Since Sentinel operates at high altitudes, it is out-of-sight and silent to the Taliban below, who never know when they are being tracked. Sentinel can also create highly detailed images of urban areas, roads, and airfields, all items that French commanders were keen on having. The same techniques developed in Afghanistan and Libya were used in Mali and were also successful there.

As much as the British politicians want to avoid peacekeeping and similar interventions, history has shown that these things tend to be unexpected and are frequently unavoidable. Sentinel is a powerful tool in ending these overseas operations quickly and with fewer casualties. Now Britain is considering keeping Sentinel in service beyond 2015. 




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