00000nam 2200000zi 4500 9.876737 CaOODSP 20221107164803 m o d f cr cn||||||||| 190718t20182018onca ob f000 0 eng d CaOODSP eng rda CaOODSP n-cn--- M103-3/42-2018E-PDF Ghoddousi-Fard, Reza, author. Characterization of apparent GPS ionospheric delay gradients over Canada / R. Ghoddousi-Fard. [Ottawa] : Geomatics Canada, 2018. ©2018 1 online resource (11 pages) : colour illustrations. text txt rdacontent computer c rdamedia online resource cr rdacarrier Open file ; 42 Cover title. Includes bibliographical references. "Differential GNSS augmentation systems require reliable knowledge of spatial and temporal variations of ionospheric effects on GNSS measurements. In addition, recent developments in Precise Point Positioning observation models can benefit from ionospheric constraints from nearby stations. This requires an understating of ionospheric delay spatial de-correlation under different ionospheric conditions. In this study vertical ionospheric delays estimated from GPS stations in Canada and adjacent regions are employed for studying spatial and temporal ionospheric gradients during periods of quiet and disturbed ionospheric conditions. Ionospheric delay differences at each pair of ionospheric pierce points from different stations and satellites are used to characterize apparent spatial ionospheric gradients over the studied region. Temporal variations were also studied by differencing vertical ionospheric delays from the same satellite and station over specified periods"--Abstract, page 1. gccst Global positioning systems Canada. Natural Resources Canada. Geomatics Canada. Open file (Geomatics Canada) 42. (CaOODSP)9.821474 PDF 711 KB https://publications.gc.ca/collections/collection_2019/rncan-nrcan/m103-3/M103-3-42-2018-eng.pdf 308444