Constellation based DORIS receiver network for ionospheric data

Study of the upper and lower atmosphere has advanced to the point where a compelling need has emerged for global real-time specification of the most important observations as inputs to climate models. For the ionosphere, plasmasphere and magnetosphere this is the local free electron density (ED); for the troposphere it is the local water vapor content (WVC). We describe a proposal made to the GEOScan geoscience collaboration for a DORIS receiver to be flown on the Iridium-NEXT constellation that would provide precise, real-time measurements of both bulk ED WVC, as well as ionospheric scintillation; and precise orbit determination to the 1-3 cm level, thus valuable to the Earth gravity science community. Iridium-NEXT is a constellation of 66 satellites in six polar orbit planes, to be deployed starting in 2015. We describe how the DORIS frequency lever arm is superior to that of GPS for ionospheric purposes, and how DORIS data is currently being used to generate TWV data sets of comparable precision to GPS and VLBI data. GEOScan data would be persistent, global and real-time. Its data would be made available publicly in near-real-time.