### Low-Cost Devices in High-Precision Kinematic Terrestrial Positioning  
The group of low-cost devices that currently provide high-precision positioning based on carrier-phase GNSS or GNSS/INS measurements includes devices from u-blox (Thalwil, Switzerland), Septentrio (Leuven, Belgium), VectorNav (Dallas, TX, USA), ComNav (Surveying Hub B.V., Hilversum, The Netherlands), and others. These devices are already installed in various road vehicles, drones, boats and satellites, and they have dramatically improved processing chains in real-world data collection. The group of low-cost devices also includes some smartphones, tablets and wristwatches with a production date of 2018 and beyond. As for testing low-cost GNSS devices in kinematic terrestrial surveys, many studies have already been conducted since the introduction of multi-constellation and dual-frequency smartphones in 2018. [PERSON] and [PERSON] showed that a low-cost real-time mobile geolocation service provides centimetre accuracy up to 15 km from the base station [13]. The problem was further investigated by [PERSON] and [PERSON] [14], who used ZED-F9P for stop-and-go topographic real-time kinematic (RTK) surveys under difficult measurement conditions. [PERSON] et al. (2022) [26] followed up on previous studies by testing the kinematic performance of RTK and post-processing of two vehicles in two different environments: once in a non-urban area with a long baseline of about 30 km with varying visibility and screened locations and once in an urban area within a radius of about 10 km with some buildings and open areas. Their experiences, especially the conclusions that the real-time kinematic solutions matched well with the post-processed solutions, served as the basis for this research. In addition, the authors' previous research relating to the interference of ZED-F9P receivers should be noted when several ZED-F9P receivers were tested under vertical and horizontal L1/E1 chirp jamming [27; 28], while the study by [PERSON] et al. [29] was extended to the L1/E1 interference of the kinematic vehicle with several geodetic receivers and two u-boxes on board, namely ZED-F9P and ZED-F9R. The year 2016 represented the first milestone in the use of smartphones in high-precision GNSS positioning. At that time, the extraction of raw observation data for post-processing (i.e., pseudorange, carrier phase, Doppler shift, and carrier-to-noise ratio (C/N0)) was introduced under the Android Nougat operating system [30]. Until then, the outputs of GNSS chipsets in smartphones were only PVT (position, velocity and time). The very next year, the first two smartphones--the Samsung S8 and the Huawei P10--were launched that could perform single-frequency carrier phase measurements. However, the most important milestone was the launch of the Xiaomi Mi8 in May 2018 with the new Broadcom BCM47755 GNSS chipset [31], which enabled the acquisition of dual-frequency carrier phase data on L1/L5 and E1/E5a for GPS and Galileo, respectively. These advances led to several studies being carried out on raw GNSS measurements on smartphones, aiming at a comprehensive analysis of the observations of the positioning quality and performance of various dual-frequency smartphones, starting with the Xiaomi Mi8 [4; 5; 7; 9; 18; 30; 32; 33; 34; 35; 36; 37]. [PERSON] et al. [38] reported that the carrier-to-noise density ratio (C/N0) of a smartphone is about 10 dB-Hz lower than that of a geodetic receiver, but the multipath is much higher. They reported that frequent cycle-slips and loss of lock already limit the accuracy of high-precision positioning in static mode but even more so in kinematic mode. In addition, the authors proposed that the duty cycles should be turned off, which resulted in better carrier phase measurement accuracy and much higher positioning accuracy. [PERSON] et al. [39] followed up this study in 2019 and investigated the quality of raw GNSS observations from smartphones in terms of C/N0, noise, carrier-phase tracking and velocity estimation.