Cruising above the Arabian Sea, a P-3 Orion of the United States Navy (USN) scans the water’s surface below for all ships in its area of operation, focusing on any watercraft that may be conducting piracy operations off the Somalian coast. A full moon illuminates the night sky, but at 15,000 feet the crew depend on their radar equipment and not their eyes to identify any targets on the choppy water.
The tool aboard the P-3 Orion the USN depends on to detect air and surface targets is the AN/APS-137 Synthetic Aperture Radar (SAR) and Inverse Synthetic Aperture Radar (ISAR) system. The APS-137 specializes in anti-surface and anti-submarine warfare. For anti-submarine missions it has the ability to locate submarines by identifying periscopes and antennas, even in rough seas.
For anti-surface missions, the APS-137 can perform long range surface searches and track multiple targets simultaneously. This makes it ideal for anti-piracy operations by locating, identifying and tracking the pirate motherships and the small skiffs they launch used to attack, board and hold for ransom merchants ships in the international shipping lanes.
On this night, 500 miles off the coast of Somalia, the P-3 crew tracks multiple targets within its patrol region, including two merchant container ships steaming south, a solitary merchant ship traveling in northeasterly direction toward the Red Sea, and numerous smaller fishing vessels. To the west and slightly ahead of the solitary merchant ship’s path, the P-3 monitors a smaller stationary craft anchored in a position where it could possibly intercept the larger ship. Two fast moving surface vessels launch from its location, both traveling at high rates of speed to an interception point ahead of the container ship.
The P-3 crew communicates with a Royal Navy Frigate patrolling the shipping lanes nearby, asking for immediate assistance to intercept the pirates. Once in range, the frigate launches two interceptor boats and a Merlin HM1 helicopter, allowing it to intercept the skiffs before they can board the merchant ship. British sailors capture and board the pirate skiffs and mothership, arresting 45 pirates and sinking all three boats.
The radar system of any aircraft is very important to ensure the safety of the crew and the success of the plane’s mission. A radar system like the APS-137 not only performs to protect a flight crew’s safety, but also enables the United States Navy to locate and track submarines and surface ships, support and carry out U.S. military operations, and provide protection of international trade relationships of the United States and its allies.
Pictured here is the receiver-pulse compressor R-2308A of the AN/APS-137. Duotech has extensive test and repair capabilities for the antenna assembly, receiver/transmitter, radar processor, and the indicator of the APS-137.