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Eurofix: Test Results of a Cost-Effective DGNSS Augmentation System

Published online by Cambridge University Press:  23 November 2009

G. W. A. Offermans
Affiliation:
(Delft University of Technology)
A. W. S. Helwig
Affiliation:
(Delft University of Technology)
D. van Willigen
Affiliation:
(Delft University of Technology)

Extract

Eurofix is an integrated navigation system, which combines Differential GNSS and Loran-C. The Loran-C system is used to provide differential corrections for the GNSS pseudo-range measurements and integrity information by additionally modulating the transmitted signals. This modulation, however, is not allowed to degrade normal Loran-C operations. As data transmission is hindered by the aggressive Loran-C signal environment, special modulation patterns and Forward Error Correcting codes are designed to fulfil the requirements. Compared to other DGNSS services, Eurofix has a number of advantages: It covers a large area, its implementation in an already existing infrastructure is basically low-cost, it offers enhanced datalink availability in urban and mountainous environment, it has wide-area capabilities and, finally, it provides a free backup navigation system in case either Loran-C or GPS fails.

The paper describes the Eurofix system, focusing on the Loran-C data channel. A modified RTCM type-9 message format is used with special Forward Error Correction. At Delft University a real-life test set-up has been built to evaluate the Eurofix performance for different scenarios. The results on datalink and DGNSS performance are presented. It is shown that metre-level DGNSS performance is achievable with low bit rate data channels, using Loran-C stations at up to 1000 km distance.

Type
Research Article
Copyright
Copyright © The Royal Institute of Navigation 1997

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References

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