Stationary Leveling and Gravity Vector Estimation in Inertial Units
Stationary leveling extracts pitch and roll by isolating the 1g local gravity vector, bounded by accelerometer bias stability and vibration rectification error.
Static Tilt Resolution
Resolution Limit
Measurement sensitivity of an accelerometer is defined by the smallest change in angular inclination it can detect when held in a fixed position. High-precision leveling systems depend on a low static tilt resolution to maintain precise alignment of structural components and machinery. This parameter is limited by the electronic noise of the sensor and the resolution of the analog-to-digital converter.
The static tilt resolution is typically specified in milli-g or milli-degrees, which describes the sensor’s ability to resolve very small angular changes.
Signal Amplification
Signal conditioning circuitry must be designed with low-noise amplifiers and high-resolution converters to capture the minute changes in capacitance generated by micro-degree tilts. These electronics must be shielded from electromagnetic interference to prevent high-frequency noise from masking the small tilt signals.
Calibration Accuracy
Establishing this resolution involves measuring the output of the sensor at different angles using a precision tilt stage in a temperature-stable, vibration-isolated laboratory. Sourcing specifications verify this parameter under controlled reference conditions before the sensor is integrated into the final application.
Environmental Stability
Thermal expansion of the mounting bracket and the sensor package can generate parasitic tilt signals that degrade the effective resolution of the system. To maintain accuracy, these thermal drifts must be compensated for by using local temperature measurements and correction coefficients.