Published online by Cambridge University Press: 23 November 2009
Any device having a property which varies as a result of its being rotated in space can, in principle, be used as the primary sensor of an inertial navigation system. A wide range of devices and properties has received attention with this aim in view. The spinning-wheel gyroscope has, to date, proved the most fruitful but a number of ‘exotic’ types of gyro show promise. The discovery that the atomic nucleus can, under certain conditions, behave like a spinning mass gave birth to ideas of a nuclear gyro of some sort. The further discovery that some nuclei possess magnetic properties opened the way to nuclear magnetic resonance and offered a method of communicating with the minute spinning masses.