Geometrics G-823RBS Caesium “Cs” Magnetometer Base Station

A complete high-performance base station magnetometer system that includes:

  • High sensitivity cesium vapour magnetometer with the CM- 201 Mini-Counter providing 0.004 nT/√Hzrms performance
  • Magnetometer data and GPS time coordinates recorded as ASCII data file on high capacity removal compact flash card
  • Low power consumption (30w) and operable from 10-36 VDC or 110-240 VAC 50-60hz external power sources
  • System includes nonmagnetic, collapsible tripod sensor stand with attachment hardware for magnetometer sensor, sensor driver/counter module, GPS antenna/receiver, and data logger
  • System comprised entirely of weatherproof components and packed in a durable watertight shipping/storage case ready for immediate use
  • Automatic measurement triggering by integrated NovAtel V1 GPS antenna/ receiver. Each magnetometer reading is concatenated with the GPS trigger time. The G-823 also accepts an external input for synchronising its measurements and the ability to concatenate its measurement data with the output of other RS-232 serial devices.

Time-stamped magnetic field measurements are presented as a serial data stream in the RS-232 ASCII format and logged by serial data logger included in the G-823RBS and are also available for recording by other external devices.



Magnetometer Self-oscillating split-beam Cesium Vapour (non-radioactive)
Magnetometer Operating Range 20,000 to 100,000 nT
Operating Zones The earth’s field vector should be at an angle greater than 10° from the sensor’s equator and greater than 10° from the sensor’s long axis. Automatic hemisphere switching.
Sensitivity <0.004 nT/√Hzrms. Typically 0.02 nT P-P at a 0.1 second sample rate (90% of all readings falling within the P-P envelope)
Absolute Accuracy <3 nT throughout range
GPS Receiver Time accuracy; 20ns, RMS, max. data rate; 20hz
Data Logger Serial logger, removable flash data storage card.
Data Format ASCII, MS Windows PC compatible, FAT16 file format.
Capacity 44 days using 2Gbyte Flash card while recording at 10hz rate with GPS receiver output set to provide GPZDA data sentence (UTC). Logger will accept 64Gbyte Flash card with FAT32 file format.
Mechanical/Environmental Shipping weight: 12.7kg
Operating Temperature -35° C to +50° C
Storage Temperature -45° C to +70° C
Altitude Up to 9,000 m
Weatherproof O-Ring sealed for operation in the rain and/or 100% humidity
Power 10 to 36 VDC, 30 Watt. or 110-220VAC (50-60hz)
Standard Accessories 110-220 VAC (50-60hz) power supply, Flash card reader, shipping/storage case, Geometrics MagMap2000 data processing and display software.


Record of magnetic field variation measured with G-823RBS at 10hz rate.

Product Brochure
Product Brochure