Ionospheric Mapping with the GPS/MET

George Hajj and Larry Romans

Abstract:	The GPS/MET experiment, which placed a GPS receiver in a low-Earth orbit tracking the GPS in an occultation geometry, has collected thousands of occultations since its launch in April of 1995. Each occultation can be inverted to give an electron density profile in the ionosphere, temperature and pressure profiles in the lower mesosphere, stratosphere and upper troposphere, and water vapor density profiles in the lower troposphere. This paper gives a summary of the ionospheric effects on the GPS/MET signal and examines some of the retrieved electron density profiles. We examine the bending induced by the ionosphere on the occulting signal and the resulting separation of the two GPS links corresponding to the Ll and L2 phase signals. We also examine the amplitude scintillation caused by sharp layers at the bottom of the ionosphere. We briefly describes the Abel inversion method for obtaining the index of refraction and show several examples of electron density profiles and comparisons to profiles derived from the Parametrized Ionospheric Model (PIM) and to incoherent scatter radar measurements.
Published in:	Proceedings of the 52nd Annual Meeting of The Institute of Navigation (1996) June 19 - 21, 1996 Royal Sonesta Hotel Cambridge, MA
Pages:	539 - 545
Cite this article:	Hajj, George, Romans, Larry, "Ionospheric Mapping with the GPS/MET," Proceedings of the 52nd Annual Meeting of The Institute of Navigation (1996), Cambridge, MA, June 1996, pp. 539-545.
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