A multi-instrument technique for localization of scintillation-causing regions in the equatorial ionosphere

Scintillation of transionospheric radio signals is a phenomenon of great practical consequence for users of satellite communication and navigation systems, often rendering these systems inaccurate or simply useless for periods of time. In order to understand the occurrence and underlying physics of the plasma instabilities that generate scintillation-causing irregularities, it is necessary to study the scale and velocity of these irregularities as well as their distribution in altitude. Scintillation is a diffraction effect; hence the observed diffraction pattern at the Earth's surface contains information on these three parameters. Often, the range is taken at an assumed altitude, allowing the velocity and scale to be estimated. However, the accuracy of these estimates depends on the quality of the assumed altitude. In this paper, we introduce the combination of field-aligned airglow images and satellite-to-satellite occultation links as a method to independently estimate the altitude of scattering regions at low latitudes. During the September-October equinox period of 2006, observations in the American sector show most irregularities in the 200-375 km altitude range.