Grad-03-500M Three Axis Marine Gradiometer
The Grad-03-500M marine magnetic gradiometer can operate in high gradients which are detrimental to other types of magnetic field sensor. It is designed for ROV mounting and operation to a depth of 5000 metres. The gradiometer contains two triaxial fluxgate elements spaced 500m apart on a stable support beam housed within a carbon fibre pressure enclosure. The unit operates from a supply of ±12VDC and provides six analog outputs representing the field in each of the six sensing elements.
The gradiometer has a dynamic range of ±100µT, a bandwidth of 2kHz and a resolution of better than 1nT.
The gradiometer outputs are trimmed during manufacture to provide good matching between corresponding channels for gain, offset and orthogonality. However, most vehicles will have a significant magnetic signature and, depending upon the application, the data may require some matrix correction processing to eliminate these effects. The matrix correction coefficients can be determined by recording data during rotation of the vehicle in a suitable low magnetic gradient area.
A separate analog correction unit, Grad-03-500ACU, is available for use with the instrument to provide a bipolar supply for the gradiometer and produce three analog outputs representing the gradient in each axis. The three gradient signals are corrected for gain, offset and mechanical alignment using 12 potentiometers. The unit operates from a supply of 9-18VDC and provides a visual readout of the gradients with a resolution of 1nT.
For some applications an array of sensors may be appropriate. The gradiometer can be used for depth of bury measurements and geophysical surveys where three-axis information will have a particular advantage in determining the direction of an anomaly.
A datalogger with cable to connect to the ACU can be provided, for connection of the system to a computer and logging of the collected data.
The gradiometer has a dynamic range of ±100µT, a bandwidth of 2kHz and a resolution of better than 1nT.
The gradiometer outputs are trimmed during manufacture to provide good matching between corresponding channels for gain, offset and orthogonality. However, most vehicles will have a significant magnetic signature and, depending upon the application, the data may require some matrix correction processing to eliminate these effects. The matrix correction coefficients can be determined by recording data during rotation of the vehicle in a suitable low magnetic gradient area.
A separate analog correction unit, Grad-03-500ACU, is available for use with the instrument to provide a bipolar supply for the gradiometer and produce three analog outputs representing the gradient in each axis. The three gradient signals are corrected for gain, offset and mechanical alignment using 12 potentiometers. The unit operates from a supply of 9-18VDC and provides a visual readout of the gradients with a resolution of 1nT.
For some applications an array of sensors may be appropriate. The gradiometer can be used for depth of bury measurements and geophysical surveys where three-axis information will have a particular advantage in determining the direction of an anomaly.
A datalogger with cable to connect to the ACU can be provided, for connection of the system to a computer and logging of the collected data.
