## 1 Introduction
### Follow-Up on Previous Research  
In the previous study of the research team of reference [17], the parameters of three RTK receivers during static measurements were investigated. The obtained results were compared with the findings of other studies [18; 19]. It was confirmed that the \(SSR\) indicator had a significant effect on the positioning accuracy. This indicates the ability of the RTK receiver to reliably process the correction signal, which has a significant effect on the accuracy of positioning. It was concluded that the phenomenon of \"false fixed solution\" can occur for several reasons: the already mentioned erroneous estimation of phase ambiguities and the noise in the correction data from the base station, as well as the influence of the environment in which GNSS operates [20]. The evaluation of the \(SSR\) indicator was described in the study of reference [6], where it was clear that the distance of the base station from the receiver can affect the ability of the RTK receiver to resolve the ambiguity of the integer part of the carrier wave. The investigation confirmed the dependence on distance. In the study of the authors of reference [20], experimental rides with a robot following a predefined path were conducted, comparing two low-cost RTK receivers (both single-frequency multi-GNSS). These devices demonstrated a \"fixed solution status\" of 94% for the u-blox Neo-M8T RTK receiver (using open source RTK processing software named RTKLib) [21] compared to the result of 71.5% of RTK receiver SkyTra NS-HP. The experiment findings of the authors of reference [22] showed that, during measurements between buildings, the success of the \"ambiguity resolution fixing rate\" (referred to as \(SSR\)) was improved from 48.4% to 85.3%. RTK receivers are more often used as reference systems providing positions or trajectories for other studies [7; 12; 23; 24], a so-called ground truth. However, the major challenge is to ensure the real accuracy of the reference system (ground truth). The ground truth must be provided by a more precise method than using a verified system. In our opinion, ground truth can be considered as very reliable if it is determined in reference to one point anchored to the ground static measurement [17]. The authors' study from reference [25] compared four types of RTK receivers also using SBAS, with one of the verified RTK receivers whose actual accuracy was burdened by the entire dynamic measurement result. Moreover, the dataset for evaluation here was significantly reduced to the selected 50 samples of each pairwise comparison. The authors of reference [22] obtained a reference trajectory using a self-developed dual-frequency high-precision postprocessing GNSS software receiver. The experiment results showed that, in the given test environment, the three-dimension precision of the relative positioning under open sky conditions was within 0.02 m. However, the study presented an evaluation of data from only two short periods of time (both approximately 6 min), where the movement speed of the measuring platform was given as approximately 5.5 m s\({}^{-1}\) without specifying the definition of the acceleration performed. The evaluation of four RTK receivers against a postprocessed trajectory with a stated accuracy of 0.005 m was described by the authors of reference [26]. Among other things, this study provided specific values describing the accuracies depending on the artificially induced delay of the correction signal. The study presented an evaluation of the RMS error (\(RMS_{err}\)) in the individual ENU components, where the horizontal error was no greater than 0.013 m in the fixed mode. The study defined a measurement scenario with a duration of 10 min but did not define the limiting speeds and acceleration of the measuring platform (only mentioned the specifications of the UAV used). Using the Oxford Oxford OxTs RT3002 reference system, the authors of reference [19] verified cheap versions of the RTK receivers, emphasising the complexity of evaluating their dynamic properties.