Comparison of the performance of medium and low level GNSS apparatus, with and without reference networks

The principle of mobile mapping is to combine some surveying techniques with results coming from a navigation apparatus. In this context there is a tendency to try to use cheaper and simpler devices, particularly for GNSS receivers. At the same time there is an increasing diffusion of reference networks of permanent GNSS stations. In this paper we investigate to what extent the differential positioning can alleviate the degradation of accuracy due to the use of medium and low level devices. Some experiments of RTK and kinematic positioning elaborated with and without corrections coming from permanent GNSS stations are described. It turns out that differential corrections significantly enhance the information acquired by medium level GNSS devices, although in some cases also stand-alone low level apparatus can have performances of unexpected good accuracy.