Holes

Ionospheric scintillation of GPS signals threatens navigation and military operations by degrading performance or making GPS unavailable. Scintillation is particularly active, although not limited to, a belt encircling the earth within 20 of the geomagnetic equator. This belt also hosted roughly half of the completed U.S. military operations in the last decade. We examined scintillation data from Ascension Island, U.K. and Ancon, Peru, in the Atlantic and Americas longitudinal sector at as well as data from Parepare, Indonesia and Marak Parak, Malaysia in the Pacific longitudinal sector. From these data, we calculate percent probability of occurrence of scintillation at various intensities described by the S4 index. Additionally, we determine Dilution of Precision at one minute resolution. Diurnal, seasonal and solar cycle characteristics are examined. Latitudinal and longitudinal comparisons are made. Our findings are consistent with previous research. Unlike previous research, however, we attempt to replace, or impute, missing S4 values in order to better capture the extent of scintillation. In doing so, we study data gaps, or holes, and characterize them.