Silicon-based Gyroscopes and Their Accelerometer Siblings Are Increasingly Prevalent in Consumer-electronics Equipment. However, Inaccuracy in Reported Data May Produce an End-user Experience That’s Worse than Not Having a Mems-based System at All. by Mark Looney Analog Devices

Although MEMS gyroscopes are simpler to integrate into electronic systems than their mechanical predecessors, many factors still require consideration, including trade-offs among function, performance, and price. For many systems, a key performance metric is accuracy. Although off-the-shelf products may satisfy some design requirements, a gyroscope that appears to suit a system design may end up being too inaccurate. Over a population of parts, for example, you can expect sufficient variation in accuracy to negatively affect critical system goals. Gyroscope calibration offers an option for bridging this gap, enabling the use of an approach that may be more favorable due to price, package style, power dissipation, or other attributes. The purpose of calibration is to translate transducer behaviors into valuable bits at the system level. A well-designed calibration takes a population of transducer behaviors and produces predictable outputs over the important conditions for the end system. Translating MEMS-gyroscope behaviors into predicable perform ance at the system level requires you to cultivate an understanding of the transducer’s performance and behaviors, establish the impact that the sensor’s behaviors will have on critical systemperformance criteria, and develop a strategy and process for characterizing and correcting behaviors that can limit the transducer’s value in the system. For system developers in the initial prototype phase, justifying the investment in accurate motor stages, encoders, and stable mechanical structures can be difficult. Although this approach to calibration will not replace the need to invest in proper equipment for production-ready processing, it will speed development cycles and lower up-front investment requirements.