Temperature Transition
Rapid changes in the environmental temperature of a device over time can induce transient errors that do not appear during steady-state operation. During thermal rate slewing, the internal components of a sensor are in a state of constant flux. This prevents the system from reaching thermal equilibrium.
Rate Specification
Manufacturers specify the maximum degrees per minute that a sensor can handle while staying within its error budget. If thermal rate slewing exceeds this limit, the compensation algorithms may fail to track the bias shift. This is particularly problematic for sensors with large thermal masses.
Error Mechanism
The lag between the external temperature and the internal sensor die is the primary cause of errors during these transitions. As the heat moves into the device, thermal rate slewing creates temporary gradients that distort the mechanical structure. These distortions appear as spikes or drifts in the output signal.
For high-precision accelerometers, this can look like a constant acceleration. Standard polynomial compensation is often ineffective because it only accounts for the temperature value, not the rate of change. Advanced models must include a derivative term to account for the speed of the transition.
Testing Protocol
Verification involves subjecting the device to various ramp rates in an environmental chamber. Minimizing the impact of thermal rate slewing is a requirement for sensors used in aerospace environments.
