Agency
Geodetic payloads on GENESIS satellite
Geodetic payloads on the metre-scale GENESIS satellite, today used to fix the position of observing stations:
| Global Navigation Satellite System | Satellite navigation, otherwise known as satnav, is one of the most widely-used geodetic techniques. Positioning of a given site is fixed continuously, using multiple satnav constellations for added accuracy, and over time becomes more and more precise down to millimetre scale, additionally revealing gradual drifts due to Earth movement. |
| Satellite Laser Ranging | This measurement method involves bouncing laser pulses off a retroreflector aboard a satellite, then measuring its two-way travel time to fix the distance the laser light has shone, down to a few millimetres. |
| DORIS receiver | France’s Doppler Orbitography and Radiopositioning Integrated by Satellite or DORIS system has been in operation for the past three decades and has become a standard data source for the ITRF. DORIS signals from satellites are compared to those coming from 60-strong receiver station network spaced across the planet in terms of their ‘Doppler shift’ – rising in frequency upon approach and sinking when moving away – to fix their relative position down to centimetre scale. |
| VLBI | Very Long Baseline Interferometry, or VLBI, began as a radio astronomy technique where observations of celestial objects such as quasars from multiple radio telescopes are combined together precisely to yield resolution equivalent to a single giant telescope. For geodesy the technique can be reversed so that the precise timings of joint observations of celestial targets can derive the exact distance between the sites. An artificial radio source aboard GENESIS will therefore serve as a common target for multiple VLBI stations down on Earth, broadcasting on at least two frequency bands. |
One or more of these instruments, once duly qualified and characterised with the GENESIS mission, could also potentially be flown on future Galileo satellites.
