Did you know that, even while you’re sitting at your desk, you’re still highly dependent on satellite navigation systems (e.g. GPS, Galileo) working correctly?
Apart from the location info as used by the satnav in your car, any GPS receiver also provides accurate timing information. This synchronization to the satellites' on-board atomic clocks is usually accurate to just several nanoseconds (1x10-12). Timing functionality from satellite navigation systems (GNSS) is nowadays highly integral in systems and networks we use continuously throughout the day.
Examples using this information include the electrical power grid, international money transfers and mobile phone networks. Loss of timing and/or positioning information could bring all these systems down, potentially causing big problems for society.
Due to the increase in crowdedness of the radio frequency spectrum and the decrease in costs of (digital) radio equipment, the probability of incidents caused by radio signal interference on the GPS and Galileo frequencies is growing by the day. Typical incidences range from jammed frequencies due to wrongly tuned transmitters, to also deliberate ‘spoofing’ of receivers causing them to output wrong times and positions.
GRATE is a team effort between Astron (The Netherlands Institute for Radio Astronomy), NLR - the Koninklijk Nederlands Lucht- en Ruimtevaart-centrum or Netherlands Aerospace Centre in English - and S[&]T.
To provide reliable positioning and timing, the consortium, is working towards the creation of a GNSS receiver with a smart antenna.
Using ASTRON’s knowledge of so-called phased arrays, the GRATE (which stands for GRound-station Array TEchnologies) receiver will use advanced beam forming techniques to focus the antenna on the visible navigation satellites. This makes it possible for the antenna to become ‘selectively deaf’ to other directions such as towards sources of interference.
Future
With the project recently passing the System Requirements Review for ESA, GRATE is well on its way in helping essential infrastructure to become more reliable!