Surface Forces: USVs No Longer Improvised


October 12, 2009: The U.S. Navy is developing a new USV (unmanned surface vessel) that is designed from scratch as a USV, not just the usual practice of taking existing small boats adapting them for remote and autonomous control. The AMN 1 is flat bottomed, so that it can better operate in shallow coastal waters, and up rivers. The navy is developing navigation software for tricky situations, like having the radar (in this case, laser based lidar) being able to detect a bridge as something it can go under, and not an obstacle to further movement. AMN 1 is equipped with most of the equipment that current USVs have been successful with.

Existing USVs (like the Israeli Protector and the American Spartan Scout) are being used to patrol coastal and port areas (the Gaza coast, and the waters around the Lebanese border, the Iraqi coast). These USVs are basically 4-8 ton, 11 meter speedboats equipped with radar, GPS and vidcams, and armed with a remote control 12.7mm machine-gun (using night vision and a laser rangefinder) There is also a public address system, to give orders to boats that should not be there. These USVs have been used for over six years. They can be controlled from an operator ashore, or in a nearby ship, usually out to the horizon or at least 10-20 kilometers distant. They can stay out 8-48 hours at a time (depending on how much high speed movement is used). The one big shortcoming is that Protector is that they are built for speed, not rough seas. So when the weather turns bad, and the waves get higher, they have to be brought in.

When Spartan Scout was particularly useful when it got its first tryout in the Persian Gulf during late 2003. There are lots of small boats moving about, some of them up to no good. An Arab linguist on the mothership was able to interrogate suspicious boats the Spartan Scout ran down. The civilian sailors were somewhat taken aback when they were interrogated by this Arab speaking boat that had no one aboard. While Spartan Scout was developed primarily to work with the new LCS (Littoral Combat Ship), every ship now wants one or more of them, just for port security.

The U.S. Navy has also developed a new USV (unmanned surface vessel) to be used by its LCS (Littoral Combat Ships) for anti-submarine warfare. Officially called the 11-meter Fleet class Anti-Submarine Warfare Unmanned Surface Vehicle (ASWUSV), the 39 foot long boats weigh 8.5 tons and can carry 2.5 tons of sensors and other equipment. The USV can move up to 63 kilometers an hour and stay at sea for up to 24 hours. Most of the time it would be moving slowly, using its sonar to search for subs. The ASWUSV is equipped with GPS and a computerized navigation system that allows it to automatically run search patterns. Thus the sailors controlling the boat remotely, can move it to an area that helicopter or aircraft dropped sonobuoys have picked up a contact, and pursue it more intensively with the more powerful sensors it has on board. Such pattern searching, worked out with algorithms derived from experience with what subs can do, have been a successful tactic since World War II.

While two of these ASWUSVs can be carried by LCS ships, the boats can also be used from shore stations. Apparently the first ones to see service will be sent to the Persian Gulf in the next three years, to help keep the Straits of Hormuz free of Iranian submarines. The ASWUSV also carries vidcams and radar, to assist in avoiding collisions with other ships, and to keep Iranian gunboats from capturing or damaging one. The ASWUSV was developed based on experience with the Spartan Scout, while the AMN 1 is building on that experience and developing new design features for the next generation of USVs.




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