A comparison of different tropospheric mapping functions by elevation cut-off tests

The uncertainties in the ground surface meteorological parameters should be introduced into atmospheric mapping function models, such as CfA2.2 and UNSW931, etc. Although these models have been developed by the ray-tracing method according to a given tropospheric profile, these kinds of atmospheric modelling errors will have an effect on the estimates of coordinates for very long-baseline interferometry (VLBI) sites. In this paper, several new mapping function models are examined. An analysis of VLBI data using different mapping function models indicated that the UNSW931 model has more powerful potential for the needs of extending VLBI measurements at low elevation angles below 5 deg.