Northrop Grumman has been helping mariners navigate for more than a century. Beginning with the first Sperry Piedmont gyroscope installed on the USS Utah BB-31 in 1911, the company today continues to partner closely with the U.S. Navy and other allies to deliver high accuracy, long duration, positioning, navigation and timing (PNT) systems.

Providing technological innovation in robust naval inertial systems, the AN/WSN-7 Inertial Navigation Systems (INS) designed and manufactured by Northrop Grumman have proliferated throughout our nation’s fleet. The company achieved a major milestone this September when the 500th WSN-7 cabinet was delivered to the U.S. Navy. Shipping the 500th cabinet is a testament to the reliability and criticality of these systems to surface and submarine platforms across the globe.

Northrop Grumman created a combination of precisely engineered hardware and software to achieve critical position accuracy and endurance, critical technology needed in a battlespace environment which relies a great deal on GPS.

The technology

The spinning mass gyroscope developed by the company near the turn of the last century was revolutionary and widely adopted as state of the art for maritime navigation. This technology was later superseded by newer ring laser gyro technology, an aircraft centric approach which provided greater accuracy, reliability and increased flexibility in terms of where and how the systems could be used.

In the 1980s, Northrop Grumman took this technology and adapted it for use on surface vessels. The company implemented and mechanized these same sensors and combined them with its own maritime know-how to get better accuracy and performance as a completely different use for this sensor. 

In the 2000s, the fiber optic gyro (FOG) was adopted for use in land and airborne systems. A key benefit of FOG technology was the ability to scale it up through use of additional fiber, which provided increased accuracy and performance. The company developed a scaled-up FOG gyro design that could meet the performance requirements of the WSN-7, and proved that significantly better performance than the base requirements for the WSN-7 were achievable. This new gyro ultimately became the core of the inertial navigation replacement sensor (INS-R) and is utilized in the WSN-12 design.

TECH INSET – How an interferometer works

If you split a laser beam into two equal paths and use mirrors to overlap them back onto a sensor, they will produce a zebra like fringe pattern that will indicate the slightest movement or distortion along the paths of the laser. This technique is called interferometry. The longer these paths are, the more precise a measurement will result. That is why going from a ring laser gyro in the WSN-7, which has an interferometer with a fixed and relatively short path length, to a fiber optic gyro in the WSN-12, where the paths can be much longer, increases precision.

“The WSN-7 has been in service with the U.S. Navy since the 1990s and will remain critical in supporting mission success for many years to come,” said Todd Leavitt, vice president, navigation and oceanic systems, Northrop Grumman. “The WSN-12 is expected to follow suit providing a more reliable and dependable PNT solution with greater precision and performance for the warfighter while using the same footprint as its predecessor.”

As the technology matures, Northrop Grumman will be able to once again find ways to improve the product and keep the evolution moving forward given the modular sensor design which was developed using digital processes and 3D engineering models. By utilizing the best technology available and adapting it to the Navy’s needs with the WSN-7, and now with the WSN-12, Northrop Grumman has completed a successful development process utilizing a model-based design which will provide a smooth transition into high rate production.

Sophisticated sensors in all domains

Northrop Grumman produces a wide variety of inertial technologies used across a wide range of domains – from undersea to outer space. The company’s products provide pointing, stabilization and navigation capabilities for a variety of applications. From the Mars Rover to satellites, from aircraft to helicopters, from ISR sensors to radars and from tanks to industrial applications such as mining, they serve operational needs of the U.S. Navy and its allies today and well into the future.