Improved Accelerometer-Based Calibration Method for High-Precision Horizontal Guidance

The precision of attitude determination in horizontal directional drilling relies significantly on accelerometer-based inclinometers. Effective calibration is essential to mitigate sensor errors, including scale factor, bias, and misalignment. In this study, deterministic errors are modeled within a unified calibration matrix framework, enabling strategic selection of reference positions to improve accuracy. Each element of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times 3$ </tex-math></inline-formula> calibration matrix is shown to depend on the spatial orientation of the sampling points, revealing a directional sensitivity in calibration accuracy. To address this, A novel calibration approach, termed equal angle interval balance correction (EABC), is proposed to minimize these orientation-dependent calibration matrix errors and to evenly distribute calibration errors across selected reference orientations, substantially reducing systematic deviations.