Since 1998, RSES has used remote Global Positioning System (GPS) equipment in the southern Prince Charles Mountains, Antarctica, to measure the present-day glacial isostatic adjustment that may be occurring there.
The GPS equipment records the phase of the incoming signals transmitted by the satellites, orbiting the Earth at around 20,000 km altitude. By estimating the satellite orbits and propagation effects that delay the incoming signal, it is possible to achieve sub-centimetre accuracy of daily coordinate positions.
The rate of change of height will provide valuable constraints on the present-day glacial isostatic adjustment and the amount and timing of melting of the Antarctic icesheet since the Last Glacial Maximum.
Each of the four sites are equipped with an Ashtech dual-frequency GPS receiver, an in-house designed and built power controlling system and low-powered computer and a satellite phone to transmit the data back to RSES on a daily basis. The systems are solar powered and hibernate during the winter when there is not sufficient solar power available to maintain operation, recommencing automatically in the spring when the levels of solar power increase.