Eurofix system and its developments

The existing Loran-C and Chayka infrastructure can, with some minor changes , become a very powerful augmentation system for GNSS (GPS, GLONASS and the future Galileo). Delft University initially proposed the Eurofix concept i n 1989. Although the necessary modification to the LF navigation systems ar e minimal, the GNSS user may get significant benefits from the Eurofix sign als in terms of accuracy, integrity and availability. The reason is the hig h signal structure, signal propagation, and the operations dissimilarity of both systems. The broadcast correction and integrity data improves GNSS ac curacy down to the metre level. In this way, the measured Loran-C and Chayk a ranges are continuously updated. Thus, in the case of GNSS signal interru ptions, highly calibrated Loran-C/Chayka may take over the navigation funct ion. Tests carried out in Europe at the Loran-C station at Sylt (Germany) d rew large international attention, leading to further tests in the USA by t he US Coast Guard in 1998. Recently, a Dutch-Russian consortium implemented Eurofix on the Chayka transmitter at Bryansk (Russia) which is now success fully broadcasting DGPS as well as DGLONASS correction data. This paper hig hlights some on-air Eurofix DGPS performance experiments carried out in Eur ope and the USA. With all the European Loran-C and Chayka transmitters modi fied, Eurofix can be used all over the European continent. As multiple stat ions can normally be received simultaneously, the user may locally apply ne tworked DGNSS, which may reduce spatial decorrelation effects significantly . Postprocessed results of this Regional Area Augmentation System are prese nted.