Global High Resolution Population Denominators Project - Funded by The Bill and Melinda Gates Foundation (OPP1134076). The dataset is available to download in Geotiff format at a resolution of 3 arc (approximately 100m at the equator) . The projection is Geographic Coordinate System, WGS84. The units are number of people per pixel. The mapping  approach is Random Forest-based dasymetric redistribution.  The methodology used to estimate the annual subnational census-based figures can be found in Lloyd et al , while the information and sources of the input population data are available here.