Periodic Reporting for period 1 - GyroRevolution (A Revolution in Rotation Sensing)
Reporting period: 2023-07-01 to 2024-12-31
Rotation sensors, also called gyroscopes, are ubiquitous in consumer electronics, navigation, and environmental sensing. The most advanced gyroscopes are ring lasers that are based on the Sagnac effect. All current compact and transportable devices, however, show significant drift and limited sensitivity, which precludes their usage in fields of application where extremely small rotation rates in the nrad/s to prad/s range need to be measured. These limitations are of purely technical origin: they derive from residual movement of the gaseous laser medium, light scattering, and acoustic fiber noise.
In this project, we seek to mplement a disruptively different design of a ring laser gyroscope that circumvents these limitations, now allowing for a compact and transportable device with near-zero drift and improved sensitivity. Such a device is in high demand for example in seismology, where it would benefit earth quake and tsunami early warning systems. Sensing of environmental ground motion is imperative in the context of climate change, ever more frequently occuring landslides being a prminent example. Monitoring the structural health of bridges and other large-scale constructions is another pressing task, where highly precise acquisition of rotation and distortion will have a massive impact on the early and reliable detection of structural fatigue.
In this project, we seek to mplement a disruptively different design of a ring laser gyroscope that circumvents these limitations, now allowing for a compact and transportable device with near-zero drift and improved sensitivity. Such a device is in high demand for example in seismology, where it would benefit earth quake and tsunami early warning systems. Sensing of environmental ground motion is imperative in the context of climate change, ever more frequently occuring landslides being a prminent example. Monitoring the structural health of bridges and other large-scale constructions is another pressing task, where highly precise acquisition of rotation and distortion will have a massive impact on the early and reliable detection of structural fatigue.
Within GyroRevolution, we set up the first prototype of such a sensor and demonstrated a sensitivity to rotations in the 10 µrad/s regime, employing novel FPGA-based hardware and fiberized telecom-grade optics. This sensor can reconstruct the full 3D rotation vector. The sensor concept is based on the so-called Sagnac effect. As optical precision metrology has matured to stunning precision in recent decades, such an optical sensor is well positioned for highly precise rotation sensing. Here, we employ servo motors to rotate the optical table along three orthogonal axes, The current sensitivity is on the order of 10 µrad/s, but offsets (null-shift bias) are on the order of 100 µrad/s. The lock-in threshold is within the noise.
To prepare for operation of the sensor in the field, we operated a comparable (but commercially available) gyroscope in an observatory for more than 100 days, unattended. Rotation data was streamed flawlessly, together with GPS-generated timestamps and environmental data. Also, we tested most of our electronics in an underground lab near Munich.
To prepare for operation of the sensor in the field, we operated a comparable (but commercially available) gyroscope in an observatory for more than 100 days, unattended. Rotation data was streamed flawlessly, together with GPS-generated timestamps and environmental data. Also, we tested most of our electronics in an underground lab near Munich.
Small and transportable rotation sensors optimized for very small rotation rates are in high demand in the field of seismology, where the wakefield also includes rotations that need to be measured at high sensitivity in a large-scale array, possibly in boreholes.
In short, within this project, we demonstrated the concept of a new type of rotation sensor, performed measurement campaigns outside the laboratory, mapped out the relevant market with its key players and already available technology, and engaged with potential customers.
In short, within this project, we demonstrated the concept of a new type of rotation sensor, performed measurement campaigns outside the laboratory, mapped out the relevant market with its key players and already available technology, and engaged with potential customers.