G05 GNSS++: Emerging Technologies and Applications

IAG (Geodesy)



25-Jun-2015, 08:30 - 10:00


 
Abstract content:

Simulated GNSS signal propagation paths during a severe troposphere weather event

The impact of transverse and downrange refractive gradients on Global Navigation Satellite Systems (GNSS) signal paths in the ionosphere and troposphere during a tropospheric storm event are investigated. The tropospheric refractive gradients from the storm event over Melbourne, Australia on 6th March, 2010 are used to determine the impact that this and similar storms have on GNSS signal paths. The traditional GNSS atmospheric retrieval methods typically assume spherical stratification of the refractivity in the atmosphere and do not take into consideration the transverse refractivity gradients acting on GNSS signals.

A three dimensional numerical ray tracing technique based on geometrical optics is used together with models of the ionosphere, lower atmosphere and magnetic field to simulate signal propagation from GNSS. The ray tracing technique involves tracing finite flux, or ray tubes and has accurate homing-in capabilities. In recent years GNSS has been increasingly used to remotely sense the Earth’s atmosphere and ionosphere using two approaches. This includes ground-based GNSS atmospheric sounding provided by a network of Continuously Operating Reference Stations (CORS) and space-based GNSS Radio Occultation (RO) using GNSS receivers on-board Low Earth Orbit (LEO) satellites. For both GNSS CORS and RO techniques 2-D signal paths are assumed and the signal path bending via transverse refractive gradients are ignored. The magnetic field effects on the signal paths are also ignored. The transverse and downrange displacements as well as the phase delay of the signal caused by the refractive gradients in the ionosphere and a severe tropospheric storm event will be presented.

 
Author(s):
R. Norman1, J. Le Marshall1,2, W. Rohm2, B. Carter1, S. Wu1, Y. Yuan1, K. Zhang1.
1RMIT University, SPACE Research Centre School of Mathematical and Geospatial Sciences, Melbourne, Australia.
2Wroclaw University of Environmental and Life Sciences, Institute of Geodesy and Geoinformatics, Norwida 25- 50-375 Wroclaw, Poland.

 

Keywords:
geometrical optics     tropospheric storm     refraction     satellites