# GNSS Multipath Detection Using Continuous Time-Series C/N0
## 3 Proposed Strong Multipath Detection Using C/N\({}_{0}\) Information
### Other Test for the Generalization of the Data  
To evaluate the presented method, 30 min data were used in Sections 2 and 3. To give a strict justification for the generalization of the data, we tested another two datasets of 1 h. One dataset was obtained from near many high-rise buildings that were likely to receive NLOS signals in Tokyo on 6 July 2020. The distance between buildings was approximately 37 m. Another dataset was obtained from near medium-rise buildings that were also likely to receive NLOS signals in Tokyo on 7 July 2020. The distance between buildings was approximately 15 m. As we mentioned regarding the proposed method, two parameters are important to detect the large pseudo-range errors. Based on the above new data sets, we verified if our presented threshold and period was suitable or not although we could not decide the best parameters. Similar to Section 3.1, satellites with pseudo-range errors over 15 m in the 90 th percentile of all errors were selected for investigation. Figure 11 shows the longest period of selected satellites for three different thresholds, 8, 10, and 12 dB-Hz, in the case of high-rise buildings. Figure 12 shows the longest period of selected satellites with three different thresholds, 8, 10, and 12 dB-Hz, in the case of medium-rise buildings. It is natural that the lower the threshold, the shorter the longest period. However, if we set a lower threshold, the number of used satellites in positioning will reduce. Thus, these settings have to be balanced. As can be seen in Figure 11, most satellites can be removed from positioning if we set 4 min as a period in the case of 10 dB-Hz as a threshold. However, GPS 11 and Galileo 03 cannot be removed from positioning because the longest period was over 300 s in the case of 10 dB-Hz as a threshold. Considering 8 dB-Hz as a threshold, GPS 11 can be removed but Galileo 03 is still left. If we set 4 min as a period and 8 dB-Hz as a threshold, the large pseudo-range error of Galileo 03 will be left for about 20 s. In reality, because pseudo-range residual checks are  
Figure 10: Flowchart of measurement check and positioning based on new concept.  
conducted after LOS/NLOS detection, as shown in Figure 10, the satellites that have large pseudo-range errors will be removed eventually if the number of satellites that have large pseudo-range errors is less. As can be seen from Figure 12, all satellites will be removed from positioning if we set 4 min as a period in the case of 10 dB-Hz as the threshold. From these two test results, although one or two satellites might be left after our new detection method of NLOS signals, most satellites can be removed from the positioning. In addition, pseudo-range residual checks after the new detection method will be effective to remove one or two satellites that have large pseudo-range errors because the residual check is basically effective when the pseudo-range error is large for only one satellite.  
Using these two datasets, we also verified the characteristics of NLOS signals in the relatively challenging areas, such as those mentioned at the beginning of Section 3. The C/N\({}_{0}\) of satellites affected by strong NLOS signals can easily reach 40 dB-Hz and above. In addition, the large pseudo-range errors of these satellites continue for a long time even though large fluctuations can be observed as shown in several satellites both in Figures 11 and 12. The C/N\({}_{0}\) values of satellites that clearly receive LOS signals do not decrease below 30 dB-Hz, and relatively high C/N\({}_{0}\) values of more than 40 dB-Hz are maintained.  
Figure 11: Longest period of selected satellites for three thresholds (high-rise buildings).  
Figure 12: Longest period of selected satellites for three thresholds (medium-rise buildings).