## 4 Conclusions  
The development of GNSS mass-market receivers is very fast, and new technologies evolve continuously. In this context some GNSS mass-market receivers that also consider the GLONASS constellation were developed in these last few months. In this contribution, the authors decided to analyse the benefits of this constellation with respect to the results available with a receiver able to track only the GPS constellation. Different positioning methods were considered in order to understand the performances both in real-time and in post-processing, and the obtained results are quite strange.  
Considering the post-processing approach, we designed tests installing both a mass-market and a geodetic antenna on a pillar with well-known coordinates (obtained with a geodetic receiver after an adjustment with Bernese 5.0 software); different sessions lengths and inter-station distances between master (real CORS or Virtual Rinex) were considered in order to generalize the results as best as possible.  
Considering a CORS station as master, the behaviour of the two receivers is not identical; the results are quite the same if a session length of ten minutes is considered; however, when decreasing the time of the survey (5 min), the results became very different: the single constellation receiver continued to provide the same results in terms of accuracy while with the NVS receiver no reasonable results were obtained. If a Virtual Rinex is considered as master station, we obtain no improvement in terms of accuracy; in all cases the u-blox receiver allowed us to obtain the best results.  
Considering the real-time approach, if a geodetic antenna is considered, the accuracy obtained with two receivers with VRS correction is the same, but the fixing percentage is different. With the u-blox receiver, about 67% of epochs can be declared as fixed _versus_ only 33% with the NVS. If the Garmin(r) antenna is considered, no result comparison is possible with the VRS correction because the NVS receiver is not able to fix any epochs: in fact all epochs are defined as float solutions and the planimetric dispersion is about 80 cm at 95%. In order to verify if the GLONASS constellation can be dangerous for the real-time positioning with this type of receiver, the authors decided to repeat the same experiments excluding the Russian constellation. In this case, the NVS receiver is able to fix the ambiguity phase in 8% of cases with respect to 97% of the u-blox. We also demonstrate the quality of the positioning when the ambiguity can be declared as fixed; we have shown that the presence of a false fix is frequent, so it is possible to affirm that the VRS correction is not a good product for these types of instruments. If a single constellation is considered, we noted an improvement in results that, despite all, does not entail the use of these instruments.  
Analysing the results obtained with a geodetic antenna respect to the Garmin one, no substantial differences in terms of accuracy can be found for both receivers. It is not the same if we consider the noise of results: nevertheless it is not possible to reach the fixing of the GLONASS phase ambiguity even if a geodetic antenna is considered both for real-time and post-processing approaches.  
The authors would like to thank [PERSON] for his contribution to assembling the instruments and [PERSON] for providing the NVS receiver.  
The work presented in this paper was carried out in collaboration with all authors. [PERSON] has carried out a literature survey, performed the tests, conceived the Matlab code to analyse the results, and wrote the paper. [PERSON] has defined the research topic, guided the research goals, edited and reviewed the paper.  
The authors declare no conflict of interest.