# An Indoor DFEC Ranging Method for Homologous Base Station Based on GPS L1 and BeiDou B1 Signals
## 3 Implementations and Evaluation
### Wireless Environment Test  
A. Test Environment Introduction  
In this section, we will carry out further tests in a wireless environment. The test scenarios are selected in our pseudo-satellite navigation test field, as shown in Figure 10. The upper left corner of the picture is our transmitting base station, the upper right corner is our multi-scenario analog antenna array, and the lower left corner is our test area. This area can simulate a variety of scenes such as viewing scenes, semi-occluded scenes and fully-occluded scenes. We carry out testing under a variety of conditions to verify requirements. The lower right corner is our test equipment. In order to avoid the introduction of human behavior jitter to evaluate the ranging results, we choose to use a small cart to evaluate the ranging effect of each characteristic test point. Figure 7: Phase difference between L1 channels after three cold starts of the receiver. Figure 8: phase difference between B1 channels after three cold starts of the receiver. Figure 9: The distance based on the phase difference is estimated by the whole number of wavelengths. Figure 11 is a floor plan of the test hall environment on the first floor. Here we selected five feature points, of which 21 and 23 are the two points in the viewing area, which are used to simulate the ranging effect in different positions in the viewing environment. Point 30 is the boundary area for viewing. In the existing tests, the positioning accuracy of this point is usually difficult to guarantee. As a feature point, we want to further evaluate whether the distance measurement method can solve the positioning problem at this point in the future. Point 1 is a semi-shielded area of the signal, but since the area is close to the stairs, the multipath phenomenon at this point is usually obvious. Point 26 is a fully shielded area, in which we can't see the position of the transmitting antenna at all. Through the analysis of the five characteristic points, we hope to find out whether the current dual-frequency ranging method can improve the impact of cycle slip and multipath on ranging to some extent. At the same time, in order to further verify the generality of the algorithm, we divided the process into two rounds during the test. After completing the data collection of five points in the first round, the second round of data collection was performed. This can reduce the probability of receiving the same signal at a fixed point. See the following sections for specific test analysis. B. Results of Wireless Environmental Testing  
Figure 12 is an estimated value of the distance difference between channels obtained by analyzing the three-point data of the through-view area 21, 23, and 30 collected in the first set of tests according to the whole number of wavelengths. Figure 13 is an estimated value of the distance difference between channels obtained by analyzing the three-point data of the through-view area 21, 23, and 30 collected in the second set of tests according to the whole number of wavelengths. It can be found from the figure that the estimated value of the whole cycles obtained in the wireless case is significantly more frequent than that in the wired case. The two estimates of 21 points, 23 points, and 30 points each have a ranging error of \(\pm\) 2 cycles. Figure 10: Wireless test environment. Figures 14 and 15 are the estimated values of the whole cycles of the channel distance difference in the two sets of tests of the signal half-shielded area 1 test point and the full-shielded area 26 test point. By comparison, it can be found that because the signal is affected by occlusion and signal multipath, the estimated value of the whole cycles is more fluctuating relative to the viewing environment, and the more severe the occlusion is, the more frequent the estimated value is. There is a ranging error of \(\pm\) 3 cycles at 1 point, and a ranging error of plus or minus 5 cycles at 26 points.