# GNSS Multipath Detection Using Continuous Time-Series C/N0
## 4 Testing and Results
### Test Results in Third Location  
The experiment was performed at our Etchujima campus in Tokyo, Japan, on 17 April 2020. The configuration of the receiver and antenna used in this test was same as that described in Section 4.1. The car was parked near a two-story building, and the standard patch antenna was attached to the car rooftop. There was a seven-story building on the other side. Therefore, it was likely that reflected NLOS signals from the side of the seven-story building would be received. Furthermore, diffracted NLOS signals were often received from the side of the two-story building. The main difference between the first two tests and this test was that the distance from the buildings was short and the buildings were not very tall. The sampling rate of the measurement data was 1 Hz. The satellite systems and frequencies used in this test were also the same as those described in Section 2.1. The total data recording period was 1800 s. The postprocessed RTK positioning was used to estimate the precise reference position. The configuration of the target location is depicted in Figure 19.  
Figure 19: Location of car and detailed images around antenna.  
Figure 18: DGNSS horizontal errors using the new method.  
The horizontal errors of the DGNSS are depicted in Figure 20. The standard deviations in the horizontal direction for E and N were 1.62 and 1.87 m, respectively. The average errors in the horizontal direction for E and N were 11.76 and \(-\)10.37 m, respectively. The maximum absolute horizontal error in the DGNSS was 22.45 m, and the 90 th percentile value obtained was 18.43 m. The accuracy was not substantially improved in the case where different minimum C/N\({}_{0}\) values were set, namely 35 and 40 dB-Hz. In reality, the fix rate was 44.4%, but the correct fixes out of the total epochs totaled only 7.5%. It was difficult for the RTK-GNSS to resolve correct ambiguities and to maintain the corrected ambiguities because the absolute position deduced from the pseudo-range based on the DGNSS was always deviated.  
The horizontal errors of the DGNSS using our new method are illustrated in Figure 21. The deviations of the horizontal error were reduced significantly from the beginning to the end, although several jumps could be observed. This indicates that the selection of multipath-contaminated satellites was effective when using our new method, particularly in mitigating NLOS signals. The maximum horizontal error was 22.33 m, and the 90 th percentile value obtained was only 4.89 m. The standard deviations in the horizontal direction for E and N were 2.62 and 2.45 m, respectively. The average errors in the horizontal direction for E and N were 2.32 and \(-\)1.55 m, respectively. The accuracy in terms of the deviation was improved using the new satellite selection method. Regarding the RTK-GNSS, the fix rate was 97.9%, and the correct fixes out of the total epochs totaled 97.1%. The standard deviations of the RTK-GNSS with correct ambiguities in the horizontal direction for E and N were 0.012 and 0.013 m, respectively.  
Figure 20: DGNSS horizontal errors.