## 2 Materials
### Study of the GNSS Receiver Convergence Time for a Specified Accuracy of the RTK Solution
During 36 completed observation sessions more than 9700 of repetitive coordinate determinations at a static checkpoint were made. For each measurement, the following information was recorded in the automatic mode with an interval of 10 s, in accordance with:  
- the name of the base point  
- the name of the measuring point  
- solution type  
- date and time of measurement  
- the height of the antenna  
- components of vectors: ECEF: \(\Delta\)X, \(\Delta\)Y, \(\Delta\)Z related to the base reference station  
- the value of the PDOP parameter at which the position was determined  
- the total number of tracked satellites, on the basis of which the position was determined  
- detailed list of satellites of particular navigation systems (GPS, GLO, GAL, BDS) that were involved in the position determination  
- coordinates (\(x\)-north, \(y\)-east, \(h\)-height) in the Polska/CS2000 system  
- horizontal and vertical precision obtained when determining subsequent positions. Figure 3: View of: (**a**) Reference station KRUR; (**b**) Skylplot satellites KRUR. Figure 2: (**a**) Static measuring point, Trimble R10 antenna; (**b**) Measurement screen of the TSC3 controller. In the experimental measurements, the Real Time Kinematic (RTK) measurement technique was used with On-The-Fly initialization (OTF), which allows the position to be determined in the \"near\" real time with the centimeter accuracy. The OTF initialization consists in a quick solution of the problem of the uncertainty of phase measurements by a mobile receiver (rover) on the basis of data telemetrically transmitted from the reference station corrections to the pseudoranges and raw data for the phase measurements. The measurements used a single KRUR reference station, which carried out continuous observations and sent corrections in the CMRx format via mobile Internet to the rover receiver. The paper includes only measurement results, in which a full solution of the ambiguity of measurements by the rover receiver was obtained. Time delays in providing correction data from reference stations to a real-time rover receiver are generally unavoidable. The size of this delay affects the accuracy of the position being determined. As demonstrated in the work [17] in the Real-time differential positioning (RTD) simultaneous use of several GNSS systems can compensate for longer time delays of delivered corrections in relation to positioning with the use of only one positioning system (e.g., GPS or BeiDou) while maintaining the same positioning accuracy. In the present paper, it is assumed that the magnitude of this delay cannot be greater than 1 s due to the fact that the positioning used the single Galileo system. The location of the base station relative to the rover receiver is shown in Figure 4. The distance of the base station from the rover receiver that performed RTK measurements was approximately 13.9 km. Both the base station and the rover receiver were located in places with favorable conditions for satellite measurements. It was assumed that the reference station and the rover receiver received the same signals from the Galileo satellites (E1, E5-A, E5-B, E5-AltBOC).