BOLLETTINO DELLA SOCIETÀ ITALIANA DI FOTOGRAMMETRIA E TOPOGRAFIA
Abstract
NRTK technology, in its different solutions, is today’s most advanced application of the topographical satellite positioning. Compared to the traditional solution of post-processing, it aims to offer the users accuracy independent from the base-rover distance, minimum occupation time at the point of observation, and immediate availability of the measurement result. Thanks to these merits, the NRTK services are rapidly spreading within the networks of permanent stations: between Veneto and Friuli, for example, a user can now choose between five distinct networks, capable of delivering a total of over 30 independent services.
This has suggested a series of tests carried out on the different network services available in the indicated area, designed primarily to ensure their reliability, both in terms of accessibility and availability of service, accuracy and repeatability.
The evaluation of these aspects is essential for the acceptance and for the establishment of a certification procedure of the NRTK measures, which hasn’t been universally recognized by the scientific and technical literature yet.
The tests described in this work consist of repeated determinations of the position of a vertex located at the intersection of the networks of Veneto and Friuli, by use of all the network services available, and was based on the making of 436 observations, divided into 25 sessions between January and April 2010.
The results are in agreement with the planimetric accuracies reported in literature, highlighting significant dispersion of the elevation component, however some critical issues in the reliability and availability of certain network services have been discovered, with possible repercussions on their use.
