Residual Error Model to Bound Unmodeled Tropospheric Delays for Terrestrial Navigation Systems at Very Low Elevation Angles

Shrivathsan Narayanan Gary A. McGraw Okuary Osechas, and Maarten Uijt de Haag

Peer Reviewed

Abstract:	This paper proposes a residual tropospheric error modeling methodology for terrestrial radio navigation systems used for civil aviation. The functional scope of this methodology ranges from elevation angles above 0.2° to zenith and aircraft distances up to 250 km. The tropospheric residual error model for aviation applications based on global navigation satellite systems (GNSS) employs a global constant to model only the variance of the zenith tropospheric delay error and is not directly applicable for terrestrial ranging. The proposed model encompasses errors from tropospheric mapping functions, zenith delay models, and atmospheric effects such as ducting. In addition, the residual error model variance is derived to consider the variability of tropospheric delay as a function of elevation angle and aircraft range. For a proposed tropospheric delay compensation model for terrestrial ranging, the resulting residual error model is still conservative and is accurate to 0.74 mm/km for elevation angles down to 0.2°, which will enable terrestrial systems to support increasingly demanding performance-based navigation systems.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 73, Number
Cite this article:	Citation Tools are available on the NAVIGATION open access site https://doi.org/10.33012/navi.732
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