Quality assessment of Locata positioning system

Abstract

AbstractGNSS has limitations or cannot be applied in specific environments with poor geometry like city streets, tunnels, bridges, quarries, mines, ports or in indoor environment in general. In 2003 Locata Corporation from Australia began with the development of a new, completely independent technology called Locata, which was designed to overcome the limitations of GNSS. Within the project “Wearable Outdoor Augmented Reality System for the Enrichment of Touristic Content” Locata system was implemented for the first time in the Republic of Croatia. The quality of the established LocataNet network and the quality of the Locata positioning are presented in this paper as the basis for future research of possibilities to use Locata in displacement measurement. Achieved positioning precision is in a range of few mm in the horizontal direction and up to a couple of cm in the vertical direction. Although high level of precision is achieved, the accuracy, i. e. the errors of positioning solutions are up to several cm. Among other things, the research presented in this paper is focused on the reasons for achieved lower accuracy that probably have their roots in the instability of the LocataLite transmitting antennas in the established LocataNet. They namely affect the estimated float ambiguities of carrier phase measurements. Potential of relative positioning is another topic of this research, because it could allow the fixing of ambiguities to integer values and result in increase of accuracy and precision of positioning.