What is DFOG?

DFOG

DFOG, short for Digital Fiber Optic Gyroscope, is patent pending technology which has been developed over 25 years involving two research institutions. DFOG was created to meet the demand for smaller and more cost effective FOGs, while increasing reliability and accuracy.

This technological breakthrough enables new opportunities for commercial and defense applications requiring always available, ultra-high accuracy, orientation and navigation. 

The next generation of fiber optic gyroscopes

Fiber optic gyroscopes have set a high standard for inertial navigation. Their performance and accuracy have been recognised for several decades, with each generation offering innovative improvements. 

The first generation of FOG made available in 1976 used analog signals and analog signal processing. The second generation was developed in 1994 and is still used to this day. It improved upon the first generation with a hybrid approach using an analog signal in the coil with digital signal processing. 

In 2021, FOG has evolved into DFOG. This third generation of FOG sets itself apart by being completely digital, providing higher performance and reliability while enabling a 40% reduction in size, weight, power and cost (SWaP-C). 

 

How does DFOG work? 

The innovations that make DFOG possible are three different, yet complimentary, technologies that have been developed to improve the capabilities of fiber optic gyroscopes.

1. Digital Modulation Techniques

DFOG Digital Modulation

DFOG uses a specially developed digital modulation technique passing spread spectrum signals through the coil. The new digital modulation technique introduced in DFOG technology allows in-run variable errors in the coil to be measured and removed from the measurements. This makes DFOG significantly more stable and reliable than traditional FOGs. It also allows a smaller FOG with less coil length to achieve the accuracy of one with a longer coil.
 

2. Revolutionary Optical Chip

DFOG Optical Chip

By integrating 5 sensitive components into a single chip and removing all the fibre splices, the size, weight and power is reduced considerably while significantly improving reliability and performance.

Distinguished Professor Arnan Mitchell, the Director of the Integrated Photonics and Applications Centre at RMIT University, was a key partner in developing DFOG technology with Advanced Navigation. Professor Mitchell is a noted authority on microtechnology and nanotechnology whose work on shrinking components of a fibre optic gyroscope onto a single chip proved to be one of the key components of DFOG’s revolutionary technology. This innovation is what allows DFOG to have a significantly lower SWaP-C (Size, Weight, Power and Cost) than other similar FOGs, all the while delivering higher accuracy and reliability. 

“By printing optical components onto a tiny chip, we are creating more compact and reliable fibre optic gyroscopes with Advanced Navigation'' says Professor Mitchell. 

 

3. Specially Designed Optical Coil

DFOG Optical Coil

DFOG employs a specially designed closed-loop optical coil, developed to take full advantage of the digital modulation techniques. The design allows for optimum sensing of in-run variable coil errors using the new digital modulation technique. It also provides a very high level of protection for the optical components from shock and vibration. 

 

What are the benefits of DFOG? 

During the last two decades, FOGs have been the gyroscope of choice for high performance Inertial Navigation Systems (INS). But their prohibitive cost and large size made them unsuitable for many applications. DFOG mitigates these limitations, while significantly improving accuracy and reliability.

DFOG makes high accuracy inertial navigation affordable and suitable for a larger number of applications, including subsea, surveying, marine, robotics, aerospace and space.