• Energy Research

When used at sea, satellite compasses are capable of determining the course of a sailing vessel with high accuracy. It is difficult to verify the accuracy declared by the device manufacturer under such conditions, as it is difficult to define a reliable reference. This study analyses the accuracy of the satellite compass in an urban setting, with the satellite signal being obscured to various extents. It is an important point in the study to refer the measurement results to a reference route, which is the axis of a tramway track, determined by the precise GNSS RTK method. The measurement data were processed in the original software developed by the authors. The results demonstrate a high 2D positioning accuracy with low height determination accuracy. The course determination errors exceed the limit values declared by the manufacturer. However, specific measurement conditions must be taken into account, which differ considerably from the typical applications of a satellite compass.

Mobile Global Navigation Satellite System (GNSS) measurements carried out on the railway consist of using satellite navigation systems to determine the track geometry of a moving railway vehicle on a given route. Their purposes include diagnostics, stocktaking, and design work in railways. The greatest advantage of this method is the ability to perform measurements in a unified and coherent spatial reference system, which effectively enables the combining of design and construction works, as well as their implementation by engineering teams of diverse specialties. In the article, we attempted to assess the impact of using three types of work mode for a GNSS geodetic network [Global Positioning System (GPS), GPS/Global Navigation Satellite System (GLONASS) and GPS/GLONASS/Galileo] on positioning availability at three accuracy levels: 1 cm, 3 cm and 10 cm. This paper presents a mathematical model that enables the calculation of positioning availability at these levels. This model was also applied to the results of the measurement campaign performed by five GNSS geodetic receivers, made by a leading company in the field. Measurements with simultaneous position recording and accuracy assessment were taken separately on the same route for three types of receiver settings: GPS, GPS/GLONASS and GPS/GLONASS/Galileo in an urban area typical of a medium-sized city. The study has shown that applying a two-system solution (GPS/GLONASS) considerably increases the availability of high-precision coordinates compared to a single-system solution (GPS), whereas the measurements with three systems (GPS/GLONASS/Galileo) negligibly increase the availability compared to a two-system solution (GPS/GLONASS).