Calibration of a rotating accelerometer gravity gradiometer using centrifugal gradients

Area of Science:

• Geophysics
• Instrument Calibration
• Gravimetry

Background:

• Rotating accelerometer gravity gradiometers (RAGG) require precise calibration for accurate measurements.
• Existing calibration methods often necessitate test masses, complicating implementation.
• Equivalent zero biases in RAGGs are influenced by intrinsic biases and self-gradients from surrounding masses.

Purpose of the Study:

• To develop and validate a novel calibration method for scale factors and equivalent zero biases of RAGGs.
• To introduce a self-gradient model accounting for surrounding mass effects and intrinsic RAGG biases.
• To establish a calibration procedure independent of external test masses.

Main Methods:

• Scale factors are calibrated by analyzing the relationship between centrifugal gradient excitation and RAGG response.
• A self-gradient model is proposed, incorporating RAGG attitude and surrounding mass parameters.
• Equivalent zero biases are calibrated by determining the parameters of the self-gradient model.
• A RAGG physical simulation system and point masses were used for calibration and validation.

Main Results:

• The proposed calibration method for scale factors is easier to implement than traditional approaches.
• Validation experiments demonstrated consistency between the self-gradient model's predictions and simulated RAGG outputs.
• The self-gradient model accurately predicts self-gradients based on RAGG attitude and surrounding mass parameters.

Conclusions:

• The presented calibration method is effective and valid for RAGGs.
• The self-gradient model successfully accounts for gravitational gradients produced by surrounding masses.
• This approach simplifies RAGG calibration by eliminating the need for test masses.