Design and development of a field-deployable vector magnetometer prototype

Vector magnetic field measurement is required in several applications including magnetic surveys, navigation and anomalies detection. We have designed and developed a vector magnetometer prototype that can be deployed in the field to survey earth’s magnetic field. Vector operation is enabled in this prototype by using the phenomenon of synchronous coherent population trapping (SCPT), and combining it with a feedback compensation mechanism. The prototype utilizes a small rubidium cell which is placed inside a three-axis field coil. Magnetic field along each axis is measured by performing a peak-lock on one of the strongest resonances produced by SCPT and compensating the external magnetic field via servo control of the three-axis field coil. Under this locked condition, the feedback current applied to each coil in the three-axis system gives a real-time, single-shot measurement of the magnetic field components. Extensive testing of the prototype is being done by performing magnetic field measurements in the magnetically noisy environment inside the laboratory and in-comparison with that of a fluxgate sensor.