[en] In order to compute inter-frequency Differential Code Biases (DCBs), the Geometry-Free combination of a GNSS signal pair needs to be corrected from the ionospheric refraction effect. Such information is obtained using either Global Ionospheric Maps (GIMs) or local models. In this work we investigate the influence of GIMs on the final value and precision of DCB solution. The study covers different ionospheric conditions, ranging from very quiet ionospheric background up to a severe ionospheric storm. In a first step, the Slant Total Electron Content (STEC) between GIMs is assessed as a function of receiver latitude, elevation mask and ionospheric conditions. Then, daily DCBs are estimated using these different GIMs, receiver and satellite contributions being separated using a zero-mean constraint.
At last, an independent estimation of DCBs is performed using Low Earth Orbit (LEO) observations (such as JASON's GPS data). This solution is compared with our ground network solution and with DCBs coming from Analysis Centers (ACs) of the International GNSS Service providing ionospheric and DCB solutions.
Research center :
Centre National d'Etudes Spatiales, Collecte Localisation Satellites
Disciplines :
Space science, astronomy & astrophysics Physical, chemical, mathematical & earth Sciences: Multidisciplinary, general & others
Author, co-author :
Wautelet, Gilles ; Université de Liège > Département de géographie > Unité de Géomatique - Géodésie et GNSS
Lestarquit, Laurent; Centre National d'Etudes Spatiales