Using a SPATIAL INS/GNSS MEMS Unit to Detect Local Gravity Variations in Static and Mobile Experiments: First Results

Area of Science:

• Geophysics
• Geodesy
• Navigation Systems

Background:

• Inertial Navigation Systems (INS) possess three-axis accelerometers capable of detecting periodic signals like solid Earth tides.
• Previous studies correlated INS data with gravimeter measurements on static points, showing potential for gravity field variations.

Purpose of the Study:

• To assess the feasibility of using a small INS for local gravity field variation measurements.
• To evaluate INS performance on a moving platform, specifically an unmanned aerial vehicle (UAV).

Main Methods:

• Utilized a SPATIAL INS with corrected temperature bias for static and UAV-mounted gravity measurements.
• Applied extensive filtering to GPS and accelerometric data to mitigate vibrations from the UAV.
• Compared second derivative of GPS altitude data with direct INS radial accelerometry to isolate local gravity signals.

Main Results:

• INS successfully detected periodic signals of solid Earth tides after temperature bias correction.
• Demonstrated a clear correlation between INS data and CG5 gravimeter measurements at various altitudes.
• Developed a method to isolate accelerometric signals related to topography and ground density variations from UAV-based INS data.

Conclusions:

• Small INS are feasible for measuring local gravity field variations, both in static and dynamic (UAV-mounted) configurations.
• Advanced data filtering is crucial for accurate measurements from moving platforms.
• This technique holds potential for high-precision gravity variation mapping influenced by topography and subsurface density.