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Panoramic Periscope: Navy to evaluate submarine imaging system that provides 360-degree view of the horizon
Seapower 06/01/2008
Richard R. Burgess
The Navy is beginning sea trials of a new panoramic periscope imaging system that may give submarines greater situational awareness for safer navigation. The system — or one based on its design — also could offer potential tactical advantages.
The Navy will evaluate an advanced panoramic imaging system on the Type 18 periscope mast of a Los Angeles-class attack submarine (SSN) in the U.S. Pacific Fleet. The Type 18 — the standard periscope deployed on the Los Angeles-class and Seawolf-class SSNs — is being upgraded with SUBIS (submarine imaging subsystem), and the new panoramic system, or one with similar capability, could augment the SUBIS.
SUBIS comprises a set of analog video and digital still cameras that record the periscopic view for enhancement by software for analysis.
The panoramic imaging system, designed by RemoteReality of Westboro, Mass., under the technical oversight of the Naval Undersea Warfare Center Division Newport in Newport, R.I., gives an instant, 360-degree omni-directional view of the horizon around the exposed periscope.
The RemoteReality imaging system “combines hardware and a software interface [and] provides submarine operators with a critical ‘quick look’ capability,” said Denny McGinn, CEO of RemoteReality. “It captures, in an instant, a full 360-degree view of activity on the surface through the use of a very high-resolution, visible light omni camera and an uncooled thermal infrared omni camera for nighttime use.”
The imaging system also can immediately display the 360-degree image on a tactical display in the submarine. The panoramic view is displayed in two complementary 180- degree strips, one above the other. A third strip is available on the display for magnification of narrower-angle views of specific targets or directions of interest.
McGinn said the third strip could be used, for example, to focus on a view 30 degrees off axis of the bow of the submarine, or on a 60-degree cone toward the closest point of land, or toward the bearing of a last-known sonar contact.
McGinn, a retired vice admiral and former commander of U.S. Third Fleet, said the system’s image processing software was designed to use modular, off-the-shelf software to “lower the degree of difficulty of integration” with the submarine.
For the sea trials, the imaging system will use a stand-alone tactical display. If produced, a 360-degree imaging system would be integrated with the submarine’s multipurpose tactical displays.
The scene captured by the periscope is recorded, so that a submarine can descend to safer depths and subject the image to intense analysis.
“You can expand it, contract it, slice it up in various segments of field of view and really have a much better understanding of what’s up there on the surface than you possibly could have with a very brief sweep of an existing periscope with a narrow field of view,” McGinn said.
The imaging system uses a parabolic mirror and lens and image processing to eliminate distortion of the panoramic image of the kind that, for example, occurs from a fisheye lens.
“In fact, it does its best work at the furthest distances on the horizon,” McGinn said, “unlike the fisheye, which tends to give you relatively undistorted imagery very close to the center of the field of view, but very great distortions out toward the edges of the frame.”
“The submarine force has long recognized the desire for an imaging system that provides continuous 360-degree imagery that provides enhanced situational awareness while operating at periscope depth without the need to continually rotate the periscope,” said Carl Lindstrom, technical direction agent for imaging and periscopes at the Naval Undersea Warfare Center, Division Newport. “Recent advances in commercial technologies have allowed the Navy and the Office of Naval Research to leverage this capability.”
Surfacing is the most dangerous maneuver for a submarine in normal operations. As the blind submarine rises from the depths through the thermal layer near the ocean’s surface, it is vulnerable to collision with a surface ship that may have missed detection by the sub’s passive sonar.
As the periscope is quickly — to minimize detection by an enemy — rotated through a 360-degree sweep to scan the horizon for surface contacts, it is possible to miss a surface contact, especially in a heavy sea state. A more thorough scan of several minutes puts the submarine at risk of collision if the approaching contact is out of its field of view.
“Having this quick-look capability will greatly improve situational awareness and add another layer of safety, especially for submarines in littoral waters,” said McGinn, citing its advantage in navigating dense shipping traffic, fishing fleets, tight straits, ports and channels and other choke points.
“Adding a 360-degree imaging and zoom capability will allow multiple operators to monitor nearby and/or approaching vessels, as well as navigation information in all directions, thereby reducing the need for multiple periscopes and operators during certain underway scenarios,” Lindstrom said.
The imaging system also has tactical applications. “U.S. submarines are increasingly operating in high-contact density environments,” said Lindstrom. “A 360-degree imaging system would allow the submarine to monitor these contacts continually while also alerting the operator when new contacts appear so that appropriate action could be taken. The sensor would also facilitate the development of new automation contact detection and tracking algorithms.”
The Navy acknowledged that a panoramic imaging system could be integrated on a tactical display with the Automatic Identification System (AIS) being installed on U.S. submarines.
AIS, an international identification transponder required on all ships 300 tons or larger, transmits a set of identification and navigational data unique to the ship.
“In the long term, contacts from 360-degree periscope imaging systems could be correlated with AIS information to quickly identify ships,” Lindstrom said. “That capability is not going to be tested with the first sensor.”
During the last two years, RemoteReality received a total of $1.5 million in contracts from the Office of Naval Research to develop the imaging system, according to McGinn, who said his company delivered the system on time and on cost. The sea trials, originally scheduled for the fall, were moved up to June.
“The Navy will use the information gained from this feasibility demonstration to refine the requirements for future 360-degree periscope sensors and systems,” said Lindstrom. “A 360-degree imaging capability is part of the submarine force imaging program of record.”
The Photonics-built periscope installed on the new Virginia-class SSN does not have a 360-degree imaging capability.
McGinn said the system, delivered to the Navy in March, meets the standards of the Navy’s SUBSAFE quality assurance program, which has stringent specifications governing submarine safety designed to ensure that a newly installed system “keeps water on the outside of the submarine.”
The SUBSAFE program originated in the 1960s after the loss of the attack submarine USS Thresher with all hands in the Atlantic in 1963 because of a material failure.
McGinn said there are many potential naval applications of 360-degree imaging on ships other than submarines, including monitoring and recording — for training and reconstruction analysis, as well as safety investigations — of flight deck operations of ships and well deck operations of amphibious warfare ships. The omnivision of such an imaging system mounted an a ship’s mast also could be used to record incidents at sea, such as the recent harassment of U.S. Navy ships by Iranian speedboats in the Strait of Hormuz.
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