# Investigation of Static and Kinematic Surveying Performance of Handheld GNSS Receiver +
## 3 Performance Analysis Results and Discussions
### Kinematic Scenario  
The collected Garmin kinematic data was first processed with the relative method. The ISTA IGS reference station, a few hundred meters away, was used as the reference station. The coordinates of each measurement epoch were calculated as an ambiguity-fixed solution using carrier phase data with Topcon MAGNET Tools GNSS software. It should be noted that the coordinates were calculated under two different satellite configurations, i.e., G-only and G&R&E combination. The observations on the L1&L5 frequencies for GPS, L1 frequency for GLONASS, and E1&E5 for Galileo constellations were used. In order to assess the attainable accuracy with the Garmin receiver, the reference trajectory should be established. In this frame, the known coordinates were calculated by processing the kinematic data collected with the geodetic receiver that was attached to the same measurement pole using the relative method. The baseline length varied from 400 to 520 m between the rover and the ISTA reference station. The differences in 2D position and height components between the Garmin receiver and known coordinates are given in Figure 5a,b as a time series.  
The kinematic dataset was also processed with the CSRS-PPP online service in kinematic mode. As mentioned before, the CSRS-PPP service produces single-frequency solutions for Garmin receiver. The PPP coordinates calculated by the service were compared with known coordinates, and the differences are plotted in Figure 5c.  
The result of all these findings for the kinematic test is given in Figures 2 and 5, the following concluding remarks could be stated:  
* When Figure 2c was examined, it was seen that the number of satellites varied between 7 and 10 for GPS (9 on average), 4 to 6 for GLONASS (6 on average), and also 3 and 6 for Galileo (4 on average). With the combination of GPS, GLONASS, and Galileo, the maximum number of satellites increased to 21, and the average number of satellites significantly increased to 14 compared to the single system. As seen here, multi-constellation observations significantly increased the number of satellites compared to single-system observations.  
Figure 5: (**a**) The differences between Garmin relative solutions and known coordinates for G-only; (**b**) for GRE combination; and (**c**) The differences between CSRS-PPP Garmin PPP solutions and known coordinates for GR combination.  
* When looking at the PDOP values (Figure 2d), it was seen that the maximum PDOP value reached 2, 5, and 8 for GPS, GLONASS, and Galileo satellites, respectively. Unlike static measurements, it was seen that GLONASS satellites had better PDOP values in kinematic measurements. It was also observed that there were fluctuations in Galileo PDOP values. In triple-configuration, an average PDOP value of around 1 was reached, with significant improvements compared to single systems.
* When Figure 2e,f were examined, it was seen that the majority of SNR values were above 35 dBHz. When we looked at the multipath values, it was seen that the multipath values were in the order of 1-2 dm for L1/E1 signals. On the other hand, it seemed that the multipath effect was greater for L5/E5 signals.
* Looking at the differences given in Figure 5, it can be seen that there were cm-level differences in both the 2D position (as a maximum of \(\sim\)8 cm) and the height (as a maximum of \(\sim\)5 cm) in the initial (static) part of the kinematic measurements for the G-only relative solution. For the kinematic chain (started after the static time period), it was seen that the differences reached to a couple of decimeters in horizontal and height components. However, it has been observed that the solution made with the GRE combination improves the solution's performance.
* Looking at the kinematic CSRS-PPP results given in Figure 5c, it can be seen that the performance of the kinematic PPP technique is far from meeting the requirements of many geodetic applications.