Sea Power - April 2016

Electro-optical (EO) and infrared (IR) imaging sensors equipped some U.S. naval aircraft dur- ing the 1960s and came of age as standard equipment in the 1970s on P- 3 Orion and A- 6 Intruder aircraft. Now, EO/IR sensors in pods or integral with the airframe are standard on all Navy strike fighters, maritime patrol aircraft and maritime helicopters.

The adoption of these sensors in the Navy’s surface fleet came somewhat later, but the surface Navy has come to value the systems for their many capabilities. They now are installed on most combatant ships and riverine boats, either integrated as a component of a weapon system or as a dedicated surveillance sensor. In either case, these gyro-stabilized sensors have greatly expanded the situational awareness and combat capability of ship and boat crews and have been integrated into some shipboard combat systems.

The human eye had been the primary sensor for ships for centuries, later augmented by optical instruments such as binoculars and telescopes. The development of radar in the early 20th century was a great advance that changed naval warfare in World War II. While radar dominated tactics, fire control and navigation, advances in optics enabled the eye to see farther and in greater acuity.

The development of electronics to enhance and
magnify optical images — including at low light levels
— and record and distribute that imagery for detailed
analysis, greatly enhanced situa-
tional awareness. The same applied
to IR cameras, operating on heat
differentials rather than light con-
trast, which enabled Sailors to see
at night as if it were day. Unlike
radar, EO/IR sensors are passive,
which is an advantage in allowing
ships to remain covert.

The primary driver for the installation of EO/IR systems on ships was the desire to augment “current sensor suites with enhanced situational awareness in the visible and infrared spectra,” said Cmdr. Jason Hall, Electronic Warfare and EO/IR principal assistant program manager for the Navy’s Program Executive Office-Integrated Warfare Systems.

“Current naval missions and functions [of EO/IR sys-
tems] include navigation, force protection, surface war-
fare, anti-air warfare and other mission support areas,”
Hall said. “Motion imagery from EO/IR sensors provides
day/night, long-range eyes on target improving the user’s
ability to recognize and identify hazards to navigation
and targets, perform threat assessment and assess intent
in accordance with rules of engagement. EO/IR sensors
also support weapon system engagements through
automatic video tracking of targets and supporting fire-
control solutions with high accuracy line-of-sight and
range at high data rates. Sensors also support assessment
of engagement effectiveness.”
EO/IR sensors can be stand-alone or fully integrated
into a gun or missile launcher. They also can aid in
many tasks, such as searching for a man overboard,
monitoring the boarding of a ship or safety observation
of small-boat operations.

The Navy began mounting the Navy Mast-Mounted Sight (NMMS) on ships in 1989. The NMMS was an adaption of the Army’s Mast-Mounted Sight, built by DRS Technologies and installed above the rotor hubs of OH-58D helicopters. The NMMS was installed on