Jan Khan, an established expert in the field of optical sensors and fiber optic gyros (FOGs), worked at one of the world’s leading optical fiber producers before joining KVH. The author of numerous published papers and patents on fiber optic gyro technology, he shared his knowledge about FOGs and his vision of the autonomous future with us.
KVH: When it comes to fiber optic gyro technology – what’s the most important factor for people to understand?
Jan Khan: People should understand that fiber optic gyroscopes offer an elegant and simple approach to providing a very high-performance rate sensor. The FOG offers many advantages to comparable technologies because of its strengths in performance such as low error characteristics, environmental stability, higher bandwidth, better bias stability and angular random walk.
It’s important to realize that while conventional FOG technology has been well established over the last 40 years, in the last two to three years the integration of new photonic technologies has started a renaissance of the fiber optic gyroscope.
KVH: How would you explain bias stability? And why is it a key parameter for inertial sensor performance?
JK: Essentially, a completely motionless FOG should have a rotation rate of zero but in the real world, all sensors drift slightly as though they were rotating. The lower that drift, the greater the long-term accuracy.
Bias stability can be defined as how much deviation or “drift” the sensor has under zero rotation rate from zero with respect to time. Having a lower bias stability means that the gyro will output its rate with lower deviations over time. The deviations are constantly integrated; therefore, the error is cumulative during the mission time.
For inertial navigation systems (INS) applications, the fiber optic gyro’s advantage in low bias stability errors (drift) means higher precision is achievable during GNSS outage periods, and lower distance travelled error over longer GNSS outage times. Therefore, navigation applications that sustain long duration missions (days to months) require ultra-low bias stability gyroscopes.
KVH: What trend in the field of unmanned and autonomous systems are you enthused about?
JK: This is a dawn of a new era where the dream of large-scale autonomy in the automobile market is being realized. I am enthused to see how autonomous navigation development for on-road use may be utilized for other large-scale commercial applications.
The recent technological developments in the field of autonomous guidance and navigation for the commercial market can only be realized by the inclusion of low cost, high reliability, high performance sensors.
KVH: What’s being talked about today that you think won’t happen the way people expect?
JK: The ultimate solution for autonomy will be realized via high performance, low cost sensors. This includes fiber optic gyroscopes seamlessly integrated with other sensors and road infrastructure to provide a safe and efficiency autonomous environment. I think the integration of autonomy will be faster than expected, with commercial freight and shipping being the early adopters and paving the way for automotive use.
KVH: What’s being talked about today that you think will happen sooner than people believe?
JK: The integration of novel photonic solutions with realizable commercial sensors is well underway. I believe we will see high performance sensors in ultra-small footprints sooner than most people believe. Placing a low cost, high performance fiber optic gyroscope in your family’s minivan is something that until recently would have been a dream.
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