# Performance Analysis of Ground Target Detection Utilizing Beidou Satellite Reflected Signals
## 5 Conclusions  
In this paper, the mechanism of detecting targets using BeiDou reflection signals was discussed, and validation tests were carried out using moving and stationary targets. The detection performance of targets was analyzed by parameters such as the I branch component data, phase difference information, and carrier-to-noise ratio information. By comparing the results from the two experiments, the following conclusions can be drawn: 1. When the target is completely in the first Fenier diffraction zone and in the footprint of the reflector antenna, the carrier-to-noise ratio of the BeiDou satellite reflector signal decreases, and it can be detected through the I branch component data and carrier-to-noise ratio information (as shown for the PRN9 satellite in the first experiment and the PRN8 satellite in the second experiment); 2. When  
Figure 23: Reflection points of each BeiDou satellite on (\(x\), \(y\)) planes in the second experiment. the target moves to different positions, the carrier-to-noise ratio of the BeiDou satellite reflection signal does not decrease due to the relative change between the positions of the target and the mirror point. When the mirror position does not appear directly below the antenna but is offset, and the carrier-to-noise ratio information of the BeiDou satellite reflection signal increases, the target can be effectively detected by using I branch compomemt data and carrier-to-noise ratio information, but there is no obvious change in phase difference information, as shown for the results of the PRN3 satellite in the second experiment. When the mirror offset distance increases, the target may appear in the second or third diffraction region of the satellite, and the reflected signal from the target can still be received. When the target moves, the change in the reflected signal is more complex than the two cases mentioned above, and a decrease and increase of the reflected signal occurs. The order of the reflected signal is related to the direction of the target motion and the position of the mirror point. In this case, the effective information of the target can be seen through the I branch component data and the carrier-to-noise ratio information; 3. In the second experiment, we can see the range of target detection using the BeiDou satellite reflection signals. Taking the second experiment in this paper as an example, the effective detection range was about 1 m in the antenna position, a range which was not available in the first experiment. 4. For the PRN23, PRN27 and PRN2 satellites, the movement direction of the target can also be related to the changes in the I branch component data. However, there are still several problems to be solved. First, it is unclear why the intensity of the reflected signal increases when the target appears. Secondly, in the second experiment, the detection range was in the direction of the target's motion, that is, about 0.5 m before the tripod with the antenna, and the detection range at other distances was not discussed. Thirdly, there has been no detailed theoretical explanation for the relationship between the direction of target motion and the changes in I branch compomemt data. Fourthly, the effective detection thresholds of different detection parameters have not been discussed in detail. In future work, the current author will focus on solving the above problems, improve the theory of using BeiDou satellite reflection signals to detect targets, and improve the practical application ability of the technology. [PERSON], [PERSON] and [PERSON] designed the experiments; [PERSON], [PERSON] and [PERSON] performed the experiments; [PERSON] analyzed the data and wrote the paper. This work was funded by the open fund project from the State Key Laboratory of Geographic Information Engineering (Grant No.SKLGIE2017-Z-2-3) and the open fund project from Aerospace Science and Technology (Grant No.105 HKTG2019102002). The authors would like to thank the Beijing Academy of Agriculture and Forestry Sciences for providing the experiment field.