More robust satellite navigation
Current Global Navigation Satellite System (GNSS) receivers provide navigation with accuracies to within a few metres, under ideal conditions such as clear weather and outdoors. However, elements such as bad weather, noise, radio interference or large buildings degrade the signal, especially in urban and indoor environments. The user community for GNSS-based services is growing and diversifying, with location-based services used by more and more sectors. The EU-funded 'GNSS reconfigurable antenna based enhanced localization' (GRABEL) project developed an enhanced GNSS receiver to provide the more rapid, reliable and accurate localisation needed by increasingly sophisticated applications. To improve signal reception, GRABEL's system combines an array of reconfigurable antennas with beam forming, a technique used in military GNSS receivers to block intentional 'jamming'. The research team successfully produced and tested a prototype with several antenna arrays (triangular, square and hexagonal) and combined this with baseband beam-forming algorithms. The main advantage provided by this setup is much better spatial filtering, thereby reducing the effect of other signals and interference. These innovative techniques enable receivers to approach their theoretical performance limits and achieve much higher performance levels. Further development will be needed to adapt this technology to mainstream consumer products — at the moment, the equipment is both expensive and bulky. However, GRABEL has opened the door to a new generation of high-performance location-aware services, especially those used by emergency services such as ambulances and rescue crews.