A mems gyroscope is Micro-Electro-Mechanical Systems type of gyroscope. It usually ranges from 1 micrometer to 100 micrometers and makes use of a vibrating element or device for its system of rate measurement. The principle behind it is that body that vibrates has the obligation to continue the vibration it gives off into its unique plane.
If the platform it is attached to changes, the vibration will therefore exert a force on the platform which can be measured and them used as an output. This system is very useful in space as you can imagine because of the plane changing. As more is discovered about the science of gyros, the more useful the devices become. They are simple devices but are quite helpful in many areas like in space and navigatiion.