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Omega Navigation in the Shadow of Antarctica

Published online by Cambridge University Press:  21 October 2009

R. Barr  and
K. B. Young
R. Barr
Affiliation:
Physics and Engineering Laboratory, DSIR, Wellington, New Zealand
K. B. Young
Affiliation:
Royal New Zealand Air Force, Whenuapai, New Zealand
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Extract

1. INTRODUCTION. Very-low-frequency radio waves were used to implement the Omega navigation system because of their low attenuation (2–4 dB/1000 km) when propagating globally in the waveguide formed between the Earth and the ionosphere. However, it became apparent in the early seventies, throughout the period when the majority of the stations of the Omega network were commissioned, that VLF signals propagating over permafrost or glacial ice could suffer anomalously large attenuations, of greater than 20 dB/1000 km, especially during the daytime. In the Northern Hemisphere problems have arisen with the heavy attenuation of Omega signals propagating over the Greenland ice sheet. In particular a very bad region for Omega coverage occurs around Winnipeg in Canada (the ‘Winnipeg Hole’). In this area Omega North Dakota suffers from ‘near field’ effects, Omega Liberia is contaminated by trans-equatorial modal effects and Omega Norway is removed by the attenuation of its signals when crossing the Greenland ice-cap. There have even been discussions on the feasibility of constructing extra VLF transmitters in Canada to alleviate this problem.

Type
Research Article
Information
The Journal of Navigation , Volume 42 , Issue 2 , May 1989 , pp. 236 - 247
Copyright
Copyright © The Royal Institute of Navigation 1989

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References

REFERENCES

1Crary, J. H. and Crombie, D. D. (1972). Antarctic ice-cap attenuation rates of VLF signals determined from short and long great circle paths. Radio Sci., 7, 233.CrossRefGoogle Scholar
2Field, E. C. and Greifinger, C. (1972). Transpolar propagation of long radio waves. J. Geophys. Res., 77, 1264.CrossRefGoogle Scholar
3Westerlund, S. and Reder, F. H. (1973). VLF radio signals propagating over the Greenland ice-sheet, JATP, 35, 1475.Google Scholar
4Burgess, B. (1972). Propagation of VLF radio waves over an ice-cap – some experimental observations. Proc. SCAR Symposium on ‘Antarctic Telecommunications’, Sandefjiord, Norway (Cambridge, England: Scientific Committee on Antarctic Research.)Google Scholar
5Kelly, F. J., Martin, A. J.Knowles, S. H.Byrd, E. S.Andrews, M., DeBlasio, L., Siegel, J., Clamons, D., Sheeley, N., Deebel, M., Priddy, T., Quinn, L. and Rhoads, F. J. (1988). Developments in Arctic long-wave propagation theory and experiments. Radio Sci., 23, 240.CrossRefGoogle Scholar
6Kershner, S. W., Raab, F. H., Reder, F. H. and Weike, V. I. (1986). VLF navigation system to supplement Omega coverage in Canada. Proc. of the 11th Annual Meeting of the International Omega Association, Quebec, Canada.Google Scholar
7Barr, R. (1987). The diffraction of VLF radio waves by the Antarctic ice-cap. JATP 49, 1.Google Scholar
8Barr, R. (1987). The effect of the Antarctic ice-cap on the propagation of Omega navigation signals. proc. of the 12th Annual Meeting of the International Omega Association, Hawaii, 1987.Google Scholar
9Galejs, J. (1972). Terrestrial Propagation of Long Electromagnetic Waves. Pergamon Press.Google Scholar
10Barr, R. (1986). The diffraction of Omega navigation signals by the Antarctic ice-cap. Proc. of the 11th Annual Meeting of the International Omega Association, Quebec, 1986.Google Scholar