Uncertainty Propagation

Mathematical Model

Combined standard uncertainty is calculated by applying the law of propagation of errors to the functional relationship between input quantities. In the context of uncertainty propagation, the sensitivity coefficients define how much each individual error contributes to the final result.

Measurement Traceability

Metrologists calculate the total system error by combining the individual uncertainties of the sensor, the cabling, the transmitter and the data acquisition unit. This works. The method for uncertainty propagation usually involves the root sum square of the independent error components to ensure a realistic estimate of the total variance.

In a custody transfer application, even a small error in temperature measurement can have a large impact on the calculated mass flow. The resulting budget provides a confidence interval. Regular calibration of every component in the chain is necessary to keep the propagated error within the limits defined by the contract.

Confidence Factor

Expanded uncertainty provides a range within which the true value is expected to lie with a specific level of probability. Applying uncertainty propagation ensures that the reported data is defensible during technical audits or commercial disputes.