Measuring instruments, systems and magnetic gradiometers

Abstract

Embodiments generally relate to a measuring instrument. The measuring instrument may comprise: a sensor to measure a property of the local environment; a mechanism configured to cause the sensor to move along a predetermined path relative to a fixed reference frame of the instrument; and a signal processing system configured to receive a processor sensor signal generated by the sensor, perform a Fourier transform on the sensor signal to identify frequency components of the sensor signal, and compare the frequency components of the sensor signal with frequency components associated with the predetermined path to determine a measurement of the property of the local environment. The mechanism may comprise a first member having a first axis and a second axis that is different from the first axis. The mechanism may be configured to cause the first member and the sensor to rotate about the first axis, and to cause the sensor to rotate about the second axis. The sensor may be spatially offset from the first axis. The sensor may be configured to measure one or more vector components of a local force field, such as a magnetic field, for example, and the measuring instrument may comprise a magnetometer or magnetic gradiometer, for example. The measuring instruments disclosed may be suited to downhole applications, such as in a measurement while drilling system, for example.