Introducing Alpha Correction

The issue of start-up drift

All high-precision gravimeters require some stabilisation after power-up. During this period, the sensor reaches thermal equilibrium and small internal mechanical effects settle. This can appear as drift in the gravity signal.

Linear drift is manageable. It can be corrected using standard survey methods such as repeat readings, base station ties and drift modelling.

Non-linear drift is more difficult. If the drift changes shape during the early warm-up period, a simple linear correction may not fully remove it. This can reduce confidence in early readings and force users to wait longer before starting useful survey work.

Our Alpha Correction reduce this non-linear start-up behaviour.

How Alpha Correction works

SMG's VBA MEMS sensor uses two resonating beams arranged above and below a proof mass. Under acceleration, one beam is placed in tension and the other in compression. The gravity signal is calculated from the difference between the two resonator frequencies.

Because both resonators are measured independently, the instrument has more information than a single gravity output. It can also monitor how the resonators behave relative to each other during warm-up and settling.

At microGal-level sensitivity, small differences between the two resonators can become visible. These may come from device-specific scale factor differences, thermal response, package relaxation or other internal settling effects. Without correction, these effects can contribute to non-linear drift in the gravity output especially during warm-up and stabilisation phases.

Alpha Correction uses the relationship between the two resonator signals to suppress this non-linear behaviour. The correction is characterised during factory calibration and applied automatically as part of the measurement process.

What the correction improves

Alpha Correction does not eliminate all drift, and it does not replace good survey practice.

Instead, it improves the shape of the early drift response. The aim is to convert complex, curved start-up behaviour into a smaller and more predictable linear trend.

That matters because linear drift is much easier to manage in the field.

In the example below showing data from 4 hours after a cold-start, applying Alpha Correction reduced the residual scatter after linear drift fitting from approximately 274 µGal down to 7 µGal.

Cold start Results with no Alpha Correction

Same cold start Results with Alpha Correction.

The most important result is not just the lower residual value. It is that the corrected data behaves much more like a clean linear drift trend, making it easier to use within normal geophysical survey workflows.

Benefits for field users

Alpha Correction gives GAIA a practical operational advantage:

• Faster readiness after power-up
• • Useful, drift-correctable data can be achieved within approximately 6 hours from cold start.
• Less unproductive stabilisation time
• • Users spend less time waiting for the instrument to settle before collecting useful data.
• Cleaner early survey data
• • Reducing non-linear drift improves confidence in readings taken earlier in the operating cycle.
• Better compatibility with standard drift correction
• • The remaining drift is more linear and easier to correct using established gravity survey methods.
• Improved field productivity
• • Particularly useful where instruments are transported, powered down, redeployed or used in time-limited survey windows.

Why this matters

Alpha Correction is an example of how SMG uses MEMS sensor architecture to improve real-world gravimeter usability, as well as our commitment not only to introducing new gravity measurement technologies but also driving forward the real world benefits our unique technology can give to field operations.

GAIA-FIELD is not only measuring gravity from a unique compact MEMS device. It is also maximizing the sensor design to improve the quality of the gravity output.

By reducing non-linear cold-start drift, Alpha Correction further demonstrates the capability of this technology in harsh field operations.

The result is a gravimeter that is easier to deploy, faster to trust and better suited to real-world geophysical survey workflows.

In Summary

Alpha Correction is a built-in, factory-calibrated feature of GAIA’s MEMS gravimeter.

It uses the instrument’s dual-resonator architecture to reduce non-linear start-up drift and produce cleaner, more linear gravity data earlier after power-up.

For users, this means: Faster survey readiness. Cleaner drift correction. More productive field operations.