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Hardware Overview

Hardware in operation at the SGF is listed below.

GNSS sites

The HERS site uses a Septentrio PolaRx3 receiver and a Leica AR25 antenna. HERT uses a LEICA GRX1200GGPRO receiver with a Leica AT 504 GG choke ring antenna.

Digital Levelling

The levelling run uses a Leica DNA03 digital level that, once adjusted to make its bubble level, scans a barcode on a staff and can measure height difference to 0.3mm.


The backscattered light from SLR laser firings is recorded by a Hammamatsu PMT. A National Instruments data acquisition card samples the PMT at a rate of 100Mhz to collect data through the atmosphere.

Absolute Gravimeter

The Micro-g LaCoste FG-5 in the SGF basement was upgrade at the end of 2012 to a FG-5X with an extended dropping chamber, new dropping mechanisms and upgraded electronics.

Virtual Radar

A Kinetic SBS-3 is being tested at the SGF which listens to the ADS-B broadcasts from planes and acquires their instantaneous positions.

Meteorological station

The temperature, pressure and humidity at the SGF is recorded by a met device, housed in a Stevenson screen 3m above ground on the HERS tower.


To observe variable brightness, due to spinning of the geodetic spheres or tumbling of inactive satellites, the light from the second telescope port can be sent to a Hamamatsu photometer.


The site hosts a British Geological Survey broadband seismometer (HMNX) that automatically contributes in realtime to BGS' British Isles seismic network.


The SGF operates an iMaser from T4Science. Installation required a thermally stable room, high quality, low-loss cabling and a large 'battery wall' to maintain power to the unit should there be a power cut. The frequency source is supplied directly to a Septenrio PolarX 3ETR GNSS receiver connected to the HERS site.

Energy Monitor

To measure and monitor the laser pulse energy a Gentec Solo 2 energy monitor is used.

Beam Profiler

A Spiricon beam profiler gives a picture of the quality of the laser beam wavefront.