Dense Regional Active Networks and High Accuracy Positioning Services. A Case Study Based on the Andalusian Positioning Network (Southern Spain)

Today, a great number of regional-scale active networks are established all over the world for multiple applications. High accuracy real time positioning services are provided via Internet and continuous GNSS data from permanent stations are freely available through public data files for post-processing. Both solutions should be referred to a compatible realization of European Terrestrial Reference System when they are combined. This paper presents the current status of a regional active network in southern Spain (Andalusian Positioning Network, RAP) and analyzes the difference, in terms of availability, time required to fix ambiguities, precision, accuracy and repeatability of RTK positioning, between single-base Real Time Kinematic (RTK) and network RTK (NRTK) approaches, both based on this dense active network. To check the RTK performance an extensive process control was undertaken across Andalusia (Southern Spain). The initial results of the tests applied on 60 geodetic sites are presented. The tests results show that, in the case of regional active networks with distances “reference-rover” less than 30 km, NRTK and nearest single-base RTK solutions present the same level of precision and accuracy. The spatial distribution of RAP stations guarantees an effective coverage within the region, but their altimetric distribution should be adjusted to the actual terrain morphology in order to achieve reliable, homogeneous and high accuracy positioning across the network. The results achieved in this applied research may be of interest to RAP users and also to other regional and local networks covering a similar area and with analogous structural characteristics.