Regional Egypt tropospheric mapping function model

It’s essential to find out the delay caused by the troposphere layer to be able to get more accurate results. The precise positioning is very essential for accurate geodetic applications e.g., Crustal deformation and military purposes. The delay is usually modeled as a zenith value and a mapping function to map it to the observed angle. The current research develops a new mapping function model for Egypt through a least square analysis using ten radiosonde stations. The proposed model is a development of Herring continued fraction equation for dry case and wet case separately. The developed model coefficients depend on latitude and day of year. The produced model as well as Niell, Vienna and Chao models are all evaluated using Precise Tropospheric Delay database (PTD). The test data are 36 days over the year 2015 representing winter, spring, summer and fall. The obtained results clearly showed the proposed model is more accurate for Egypt than other models for both dry and wet cases.