2017-08-21 By Robbin Laird and Norman Polmar
Undersea warfare is becoming more complex as an increasing number of nations are operating submarines, advanced submarines and seafloor mines are being proliferated, and there are an increasing number of seafloor military and commercial activities world wide. Thus, there are increasing demands for navies to have enhanced capabilities to carry out surveillance to support anti-submarine warfare, mine countermeasures, general surveillance, and “special missions” in the depths.
Further, because of the need for rapid-reaction to crises and the varied ocean operating environments, these surveillance capabilities must be deployable by surface ships and small craft, submarines, and aircraft, especially helicopters. This situation must be met by advanced, flexible, and highly capable sensor platforms.
Lethal Threats
Mines are major threats to warships as well as commercial shipping. According to mine warfare analyst Dr. Scott Truver. “Enemy mines caused massive numbers of U.S. ship losses in the last century, during both wars and crises,” he explained. “During the late 1980s and early 1990s a U.S. guided missile cruiser, a large helicopter assault ship, and a frigate were heavily damaged by mines in the Arabian Gulf,” Truver recalled. “
And many more vessels were mine victims during the ‘tanker war’ in the Gulf .” While potential enemies also have anti-ship missiles and torpedoes to threaten ships, “mines can be quickly and surreptitiously laid by surface ships—including simple junks, fishing boats, and other coastal craft—submarines and aircraft.”
“Indeed,” Truver underscored, “the U.S. Navy’s experience underscores the lethality of the threat. Of the 19 U.S. Navy ships that have been seriously damaged or sunk by enemy action since the end of World War II, 15–nearly 80 percent––were mine victims.”
Potential American adversaries are estimated to have on the order of 236,000 naval mines––China has upwards of 80,000, Iran 6,000, North Korea about 25,000, and Russia more than 125,000. The global mine order of battles in 2017 totals about a million sea mines of more than 400 types in the inventories of more than 50 navies (including the U.S. Navy) worldwide.
This array of threats coupled with other beneath-the-surface missions demand advanced underwater surveillance and detection systems. Potential non-military missions include monitoring and surveying seafloor areas for underwater structures, pipelines, etc.
The SAMDIS Solution
Advanced Acoustic Concepts, a DRS/Thales joint venture based in the United States, has devised SAMDIS––Synthetic Aperture and Mine Detection Imagery Sonar––a system with multiple capabilities that can be rapidly deployed to provide the underwater “big picture.”
Having also developed shipboard hull-mounted sonars, variable-depth sonars, and a fully automated drone launch and retrieval system, the firm has devised SAMDIS primarily to be deployed from unmanned underwater vehicles (UUVs) and unmanned surface vehicles (USVs), i.e., the so-called “ghost fleet.”
However, the system in a towed configuration with a different form factor called T-SAM (Towed-SAMDIS) can be deployed from unmanned surface vessels, and it can be deployed and towed in seas up to sea state four.
The SAMDIS multi-aspect AN/ASQ-series sonar currently provides the only technology that can detect and classify sonar echoes in a single sweep and can collect bathymetry and seafloor imagery simultaneously.
With respect to mine countermeasures, the operational benefit is considerable, particularly when the goal also is to define the type of device required to destroy the mine. The SAMDIS system provides a unique capability for multi-aspect processing of ultra-high-resolution synthetic aperture sonar capability. This multi-aspect photography capability enables it to simultaneously examine an object on the seabed from three different viewing angles, hence greatly increasing the search rate.
It also is able to provide for single-sweep detection and determination for on-the-fly, real-time intelligence of the seabed. And, SAMDIS can produce images with far better resolution and contrast than the previous generation of sonar imaging technology currently in use today by many Navies.
This maximizes detection and classification effectiveness, minimizing the number of false alarms—one of the major challenges of mine-detection systems—SADMIS users will be able detect and, if necessary, clear mines more rapidly than with older methods.
While mine countermeasures is a concern of many allied nations, SADMIS also has direct value in several other areas of undersea warfare and surveillance operations such as “intelligence preparation” of the environment.
Real-World Experience
SAMDIS has been in production for four years and is in operational service with several allied nations. In particular, Britain and France employ SADMIS in their joint mine countermeasures program. The system is software upgradable, which means that experience with the now deployed and operational systems can easily provide data for software upgrades of contemporary as well as future versions.
Also, because SAMDIS is platform agnostic and scalable, it can be deployed on a variety of current and future platforms. Although especially configured for deployment from unmanned underwater vehicles, it can be deployed from unmanned surface vehicles. These could be hosted by the U.S. Navy’s littoral combat ships (LCS) or other naval or commercial ships of opportunity.
In October 2016, GPS World reported on the results the multinational Unmanned Warrior exercise. “These systems can help protect our Sailors and Marines from some of the Navy’s dull, dirty and dangerous missions, like mine countermeasures,” according to the U.S. Chief of Naval Research Rear Admiral Mat Winter. “Additionally, these systems can increase our capabilities at a more affordable cost of the conventional systems we currently employ.”
The “Ghost Fleet”
In February 2017, Defense News reported that the Navy was working to develop quickly a “ghost fleet” of numerous surface, air and undersea drones that would synchronize a wide-range of combat missions without placing sailors and Marines at risk. Captain Jon Rucker, program manager for unmanned maritime systems in the LCS program outlined top-level requirements: “We want to have multiple systems teaming and working together, surface, air and undersea.”
Rucker explained that the Pentagon and the Navy are advancing this drone-fleet concept to search and destroy mines, swarm and attack enemies, deliver supplies and conduct, reconnaissance and surveillance missions, among other tasks. These capabilities could operate in a combat environment with little or no human intervention after being programmed for the specific role.
Defense News noted that the Navy’s Office of Naval Research has been working closely with the Defense Department’s Strategic Capabilities Office to fast track this technology into an operational service.
Dr. William Roper, the DOD capabilities director, explained that much of this effort involves merging new platforms, weapons, and technologies with existing systems in a way improves capability while circumventing a lengthy and often bureaucratic formal acquisition process.
For example, USVs and UUVs configured for MCM search, detect, localize, classify, identify, and neutralize/exploit tasks could take advantage of the “off-the-shelf” SAMDIS system, which already has been demonstrated in Navy tests. In addition to autonomous operations by a UUV with SAMDIS, a tow-configured SAMDIS could deploy from the in-development Common Unmanned Surface Vehicle (CUSV).
And in that regards the Arctic is an area of growing interest. UUVs equipped with SAMDIS can have a key role in helping the U.S. Coast Guard to conduct its missions in this vital economic, security and defense area of interest. As Admiral Paul Zukunft, U.S. Coast Guard Commandant, explained: “It would make sense for UUVs to be part of the Coast Guard’s future, and we would start with the Arctic as a key area for such operations, to gain enhanced situational awareness in the region.”
A True Breakthrough
SAMDIS represents a true breakthrough in mine countermeasures, a sector that previously was the exclusive preserve of specialized minecraft with hull-mounted sonars and dedicated mine-hunting helicopters. The system provides a new approach to undersea warfare, particularly MCM, permitting a variety of platforms to employ SAMDIS to give an almost holistic picture of the seabed area.
This could be particularly significant in coastal areas, where there are seafloor wrecks and other objects that could confuse other acoustic systems.
The Advanced Acoustics/Thales team looks to have an affordable, effective solution for defeating our adversaries’ mines in some future crisis or conflict. U.S. Navy demonstrations and tests have confirmed SAMDIS operational capabilities, while four allied navies have also reported meeting operational requirements.
“A mine is a terrible thing that waits,” Dr. Truver reminds us. With SAMDIS the U.S. Navy needs to wait no longer for cost-effective and proven underwater sensors for mine countermeasures and other important undersea warfare tasks.