Sensorendrift

Sensorendrift, or sensor drift, refers to a gradual, time-dependent change in the output of a sensor that is not caused by changes in the measured quantity. Over time the sensor's baseline shifts, and the relationship between input and output can deviate from its original calibration. Drift can accumulate and degrade accuracy, sometimes leading to biased measurements if unchecked.

Drift is caused by aging of sensing materials, drift in electronics, temperature dependence, mechanical wear, moisture ingress, stress relaxation, supply voltage variations, and exposure to radiation or chemical environments that alter sensor properties. Some types of drift are bias drift (offset), others are gain/scale drift, and still others are nonlinear or hysteretic changes.

Drift is often characterized by long-term monitoring, reference measurements, and aids such as Allan variance for time stability. Many systems use redundant sensors or reference channels to separate drift from the measurand. Calibration against traceable standards at regular intervals is standard practice.

Mitigation includes temperature compensation, calibration scheduling, drift models, regression-based correction, sensor fusion, redundant sensing, robust hardware design, and protective enclosure. Selection of sensors with low bias stability and low aging is another approach.

Drift can impact process control, navigation, surveying, and medical instruments, triggering alarms if thresholds are surpassed. In practice, managing sensor drift combines hardware design, calibration strategy, and data processing to maintain accuracy over the sensor's service life.