The Still Amazing Honeywell Ring Laser Gyroscope

What is a ring laser gyroscope (RLG)?

A Ring Laser Gyro (RLG) is a gyroscope that uses the optical Sagnac effect to sense rotation. Most commonly, the RLG is filled with a gas, such as Helium Neon (HeNe), and electrodes are used to excite light waves traveling in the clockwise (CW) and counterclockwise (CCW) directions. The light waves travel around an enclosed path steered by a series of mirrors, forming an optical cavity. In the presence of rotation, the clockwise and counterclockwise directions will have different path lengths due to the Optical Sagnac effect. Since the light waves are confined to an optical cavity, the difference is path lengths results in a frequency splitting between the CW and CCW light waves. The difference of frequencies is measured to determine the rotation rate.

Today’s RLGs are more accurate, rugged, reliable and versatile than ever. One of our signature products – the GG1320AN Digital RLG – is the heart of many of the world’s most advanced inertial navigation systems. Every day they provide positioning data that enables the precise navigation and stabilization of aircraft, spacecraft, ships and land vehicles. Honeywell RLGs bring people together, provide for our national security, help us explore the universe around us – and much, much more.   

Thanks to innovation and continuous improvement, the RLG is every bit as relevant today as it was when it was first introduced. There are competing technologies out there, but Honeywell’s GG1320AN is the navigation sensor of choice for most applications because it has a price-to-performance ratio that is world-class. The marketplace agrees because Honeywell has produced more than 500,000 GG1320ANs so far.

Just like earlier generations of RLGs, the units coming off our assembly line today use two laser beams traveling in opposite directions over a ring-shaped path defined by three mirrors. The gyro measures the frequency difference between the two beams to define angular velocity, which helps determine the direction that the aircraft or other platform is headed.

Standing on the shoulders of our predecessors, Honeywell engineers have continued to make significant improvements to the RLG design over the years. For example, advanced digital electronics have improved the gyro’s accuracy to point where it typically “drifts” only 0.0035 degrees per hour, which equates to about a mile of drift per hour of flight.

We also have made significant reductions in size, weight and power consumption. Reliability is a hallmark of our RLGs, and are designed to perform under the most rugged conditions imaginable. Our factory is a showplace for the use of robotics, automation and our unique Honeywell Operating System processes that help our skilled technical workforce achieve unprecedented levels of safety, quality and efficiency.

Robust factory test,  calibration capabilities, and a commitment to understanding performance of the gyroscope with exquisite and rigorous life testing are critical to producing navigation sensors that deliver the kind of performance customers have come to expect from Honeywell, a company that has been in the navigation business for more than a century. We started in the days when “spinning iron” gyros were used to guide ships and airplanes. Modern RLG-based navigation systems are proof positive that we’ve come a long way since then.

I’m proud to be part of the Honeywell team that is building on our past successes to advance the science of inertial navigation. We’ve come a long way and have achieved a lot, but we’re excited about the future and are already working on the next generation of ring laser gyros.

For more information about our GG1320AN Digital RLG, please click here.