Noise Characteristic
High-frequency white noise on the output rate signal of an inertial sensor accumulates into an unbounded uncertainty in orientation over time. In rate gyroscopes, angular random walk quantifies the standard deviation of angular position error generated per square root of operating time, expressed in degrees per square root hour. The metric isolates broadband phase-independent thermo-mechanical noise within sensor pickoff circuitry and resonant structures, setting the fundamental limit on short-interval integration precision before low-frequency drift dominates.
Extraction Method
Allan variance computation isolates this parameter by identifying the slope of minus one-half on a log-log plot of cluster time against root Allan variance. The value at an integration time of exactly one second yields the coefficient directly. Test procedures require stable mounting on an isolated seismic foundation within a thermally shielded enclosure to prevent external micro-vibrations from corrupting broadband white noise observations.
Qualification Standard
Procurement specifications reference IEEE standard 952 for fiber optic gyroscopes or IEEE standard 1431 for Coriolis vibratory gyroscopes during baseline qualification. The manufacturer certifies the value under fixed laboratory ambient conditions, yet mechanical acoustic noise, external vibrations, supply rail ripples and digital sampling jitter can degrade the operational figure in field installations. Acceptance screening requires multi-hour stationary continuous recordings across the full operating temperature envelope.
Integration Penalty
Dynamic navigation filters rely on verified white noise bounds to assign state covariance weights during sensor fusion. Underestimating this stochastic rate error causes dead reckoning algorithms to over-trust rapid gyro measurements during aggressive vehicle maneuvers, resulting in uncorrected attitude heading dispersion.
