## 1 Introduction
The U-blox ZED-F9P receiver and ANN-MB-00 patch antenna were used, and the collected data were processed with RTKLIB software (demo5_b33b). The study concluded that displacements above 10 mm could be determined with low-cost equipment on short baselines, but accuracy was often insufficient. In the study by [27], the performance of low-cost GNSS equipment in determining horizontal displacements was examined using two different antenna types (low-cost patch and survey) and the PPP method. The results indicated that, with the survey antenna and PPP method, displacements of 20 mm within 3 h could be determined with an RMSE of 6 mm. It was also noted that the low-cost patch antenna was highly sensitive to multipath effects, and with 6 h of measurements, displacements of 30 mm could be determined with an RMSE of 15 mm. Ref. [28] conducted a study testing the performance of low-cost GNSS receivers in monitoring dynamic movements. In the study, the U-blox M8T receiver and patch antennas were utilized, and it was noted that low-cost GNSS receivers could determine the modal frequencies of bridges within the range of 0.362 Hz and 1.680 Hz. Ref. [29] investigated the accuracy of low-cost GNSS receivers in position determination using the RTK method applied in geodesy. The study reported accuracy values of \(\pm\)5.5 mm for the horizontal position and \(\pm\)11 mm for the vertical position. In the study by [30] low-cost GNSS receivers were employed to monitor displacements. The U-blox Neo-7P, a single-frequency and low-cost GNSS receiver, was used in the study. It was mentioned that on short baselines, displacements exceeding 15 mm in the horizontal direction could be determined using single-frequency and low-cost GNSS receivers. In the study conducted by [31], the per formance of low-cost GNSS receivers and antennas was tested in urban areas, and the positioning accuracy of the RTK method was reported to be between 10 and 30 mm in the open-sky and urban areas. In [32], the performance of the low-cost GNSS system in positioning using the PPP-RTK method was tested. The results demonstrated that the u-blox ZED-F9P GNSS module could achieve centimeter-level positioning accuracy. The objective of this study is to investigate the accuracy of determining horizontal displacements using low-cost GNSS receivers and antennas through the relative positioning method. To achieve this goal, displacements of different magnitudes were generated using the simulation equipment described in the following section. The data collected for determining displacements based on the measurement time with the low-cost GNSS receiver and antenna were processed using the GAMIT/GLOBK (v10.7) GNSS software [33]. Unlike previous studies, this research specifically explores the accuracy of determining horizontal displacements with low-cost GNSS equipment using the relative positioning method. Additionally, this study aims to identify the range of detectable displacements using GNSS relative positioning and to assess the impact of measurement time. Thus, the aim is to determine whether low-cost GNSS systems can serve as alternatives to geodetic GNSS systems in engineering measurements such as monitoring landslides and tectonic movements, where high accuracy is required. During the processing stage, IGS points were specifically chosen as reference points, similar to the approach used in studies monitoring tectonic movements. This was aimed at determining the performance of low-cost systems especially in monitoring tectonic movements. This study consists of three main sections prepared for this purpose: Materials and Methods, Results and Discussion, and Conclusions. In the Section 2, the GNSS equipment used in this study, the test environment, and the conducted test procedures are described. The Section 3 examines the displacement values and their accuracies obtained through the processing of GNSS data. Finally, the Section 4 interprets the displacement determination accuracy using low-cost GNSS systems.