Instrument Metrology
Accelerometer performance under stable conditions defines the statistical consistency of output offsets when the device undergoes repeated power cycles. sub-micro-g bias repeatability measures the standard deviation of these gravitational offsets as the sensor remains undisturbed between test cycles. Mechanical noise or thermal gradients introduce variations that limit the precision of the output. Engineers verify this parameter by isolating the housing from seismic vibrations while maintaining a constant temperature environment.
Measurement Protocol
Test operators calculate this characteristic by performing sequential gravity alignment procedures on a dedicated rate table. The sensor resides on a high-stability fixture to ensure the input axis aligns precisely with the local gravity vector during each iteration. Environmental controls reduce convective airflow that otherwise introduces thermal drift into the bias data.
Data acquisition systems record the static output over extended periods to establish a baseline for long-term stability.
Performance Limitation
Electronic circuitry and internal stress relief in the proof mass assembly dictate the achievable bounds of this repeatability. Dielectric charging or gas damping variations often mask the inherent resolution of the transducer. Thermal expansion coefficients create shifting zero points that complicate the separation of bias shift from noise floor irregularities.
Small mechanical offsets persist despite rigorous calibration efforts because the material structure retains slight hysteresis across temperature transitions.
Certification Requirement
Calibration laboratories confirm the stability of sub-micro-g bias repeatability to satisfy high-precision navigation system specifications. Manufacturers state this value on data sheets as a definitive limit of the sensor measurement capability. End users verify these figures by correlating laboratory results against performance observed during operational deployment cycles.
Sensor reliability depends upon maintaining this statistical alignment across the entire service life of the hardware.
