# Sampling Rate Impact on Precise Point Positioning with a Low-Cost GNSS Receiver
## 4 Conclusions  
The performance of a multi-constellation low-cost GNSS receiver was evaluated at high sample rates for kinematic- and static-PPP modes. The coordinates of different scenarios were calculated using the online post-processing service CSRS-PPP in its new version of ambiguity resolution PPP-AR. According to the results presented, the following statements can be concluded:  
1. The low-cost GNSS receiver presented high horizontal accuracy, nevertheless, the vertical component was the most affected. In both components, the obtained results were  
Figure 16: Convergence time achieved for solutions of the PPP method in static mode.  
Figure 17: Convergence time achieved for solutions of the PPP method in kinematic mode.  
calculated without considering the low multipath suppression of the antenna of the low-cost GNSS receiver. Likewise, the antenna of the low-cost GNSS receiver did not have an IGS calibration or circular polarized antenna (irregular gain pattern and low multipath suppression), this affected the convergence in some circumstances making it slow (if the antenna is compared with geodetic-grade hardware).
2. The results obtained at different sampling rates show that the low-cost GNSS receiver had a better performance (obtained positioning) by using PPP-static mode when the sampling rate was at 1 and 15 s.
3. As was presented in Figures 14 and 15, the low-cost GNSS presented data loss at 5, 15 and 30 s, and lower precision at 5 and 30 s. On the other hand, when the data were processed at high frequencies (0.1 and 0.2 s), the precision that was achieved was low in comparison with a 1 s sampling rate.
4. An improvement of convergence time is clearly seen (Figures 16 and 17) for the sampling rates of 0.1, 0.2 and 1 s. In the same way, the convergence time was reached at \(\sim\)50 min in static mode. In the kinematic mode, the convergence time at each interval time was variable and constant with the behavior presented. The convergence was affected by the cycle slips presented or by a high multipath, nevertheless, it was faster than the static mode.
5. For the high frequencies a low-cost GNSS receiver is a viable option for obtaining cm solutions if the project allows it.
6. According to the results obtained, the low-cost GNSS receiver could be implemented in structural health monitoring systems, mainly due to the centimeter precision achieved in positioning. In addition, it could represent a potential economic alternative by replacing high-cost instruments used in SHM processes.  
Finally, the use of low-cost GNSS receivers is suitable for applications such as: monitoring, mapping and positioning. The use of them depends on the characteristics of the project. The impact of the antenna in the low-cost GNSS receivers is one of the most important factors when processing GNSS observations, thus it is important to evaluate the performance and accuracy that can be achieved with a low-cost GNSS receiver with a geodetic grade antenna. Likewise, it is important to analyze the capability of new low-cost GNSS receivers in tracking more signals and other constellations, this could improve the obtained positioning and coverage.  
Conceptualization, R.R.-A. and D.H.-A.; methodology, R.R.-A.; software, R.R.-A., J.R.V.-O. and D.H.-A.; validation, R.R.-A., D.H.-A. and J.R.V.-O.; formal analysis, R.R.-A. and D.H.-A.; investigation, R.R.-A. and J.R.V.-O.; resources, R.R.-A.; data curation, R.R.-A., [PERSON] and [PERSON]; writing--original draft preparation, R.R.-A.; writing--review and editing, D.H.-A.; visualization, J.L.C.-Z.; supervision, M.E.T.-S.; project administration, D.H.-A.; funding acquisition, R.R.-A. All authors have read and agreed to the published version of the manuscript.  
This research was funded by CONACyT (Consejo Nacional de Ciencia y Tecnologia) and the Autonomous University of Sinaloa, in Mexico, grant number CVU: 429125.  
Not applicable.