Analysis of Global Positioning System (GPS) radio occultation measurement errors based on Satellite de Aplicaciones Cientificas-c (SAC-C) GPS radio occultation data recorded in open-loop and phase-locked-loop mode

The error characteristics are derived by applying dynamical error estimation, i.e., without using any external data. The computed error profiles show that the mean measurement errors are the smallest in the height range between about 5 - 7 km and 20 - 25 km, about 0.2 - 1% for bending angles and 0.1 - 0.2% for refractivity at all latitudes.

The largest measurement errors are found in the lower troposphere, where the mean bending angle measurement errors are within the range from 1 to 6%, whereas the mean refractivity measurement errors are within the range from 0.2% to 1%. From the error distributions, it is found that the occultation-to-occultation variability of the measurement errors generally spans one order of magnitude. The bending angle error correlation length is about 1 km and 100 m, at high and low altitudes, respectively, corresponding approximately to the cutoff frequency of the applied noise filters.