# Localization of GNSS Spoofing Interference Source Based on a Moving Array Antenna
## 4 Simulations and Results
### Simulation Scenario  
In this section, we describe a simulation scenario where four real satellites and one spoofing jamming source are set up. The coordinates of the real satellites are set to \([0\;0\;20,200,000]\), \([4,430,168\;18,898,507\;20,200,000]\), \([7,920,758-1,265,592\;20,200,000]\), and \([-15,905,180\;5,155,887\;20,000,000]\), respectively, with the coordinate units being  
Figure 7: Flow chart of the proposed method. meters. The subsequent coordinates in the article are also in meters. The simulation experiments employ the GPS L1 C/A signal (with a carrier frequency of 1575.42 MHz), while the four satellite transmission signals are denoted as Sta1-Sta4, respectively. The satellite signals emitted by the spoofing interference source are consistent with the real signals. The receiving antenna array adopts the \(6+1\) array antenna model in Section 2.1, and the spacing between array elements, denoted as \(R\), is set to \(\lambda/2\), where \(\lambda\) represents the wavelength corresponding to the carrier frequency. The schematic diagram of the simulation scenario is presented in Figure 8, with the interference monitoring area set to \(1\) km \(\times\) 1 km \(\times\) 200 m. To evaluate the method's location effectiveness under various monitoring paths, five typical array antenna-based signal monitoring paths are set in combination with practical application. Path 1 moves in a straight line from the initial coordinate \([0\;0\;50]\), along the same height, to the final coordinate \([1000\;1000\;50]\), with no relative displacement on the \(z\)-axis of the coordinate system. Path 2 proceeds in a straight trajectory from the initial coordinate \([0\;0\;0]\), following the diagonal direction within the monitoring region, to the termination coordinate \([1000\;1000\;200]\). Path 3 is a circular trajectory of radius \(500\sqrt{2}\), centered at \([500\;500\;50]\), which exhibits no displacement along the \(z\)-axis. Path 4 is an elliptical trajectory that covers the entire surveillance area. The center of the ellipse is \([500\;500\;100]\), and the normal of the plane of the ellipse is perpendicular to Path 2. Path 5 moves in a straight line from coordinate \([0\;0\;0]\) to coordinate \([1000\;1000\;0]\) and then from coordinate \([1000\;1000\;0]\) to coordinate \([1000\;1000\;200]\). The five paths are each divided into 41 evenly spaced observation points to collect data, resulting in a total of 205 observation points. In practice, we find that the monitoring path has a larger impact on the signal location and search effect, but the relevant study content is smaller. Thus, typical monitoring paths are established in this paper to test the performance of the algorithm under different paths and, thus, guide the practical application of the method. The set of five paths are common paths in engineering practice that have relatively acceptable monitoring performance under the conditions of a given monitoring area. The characteristics of each path are described as follows:  
* Path 1 corresponds to the setting of covering the monitoring area with the shortest path at a fixed monitoring height under the condition that the monitoring platform  
Figure 8: Schematic diagram of the simulation scenario. height cannot be raised (such as limited airspace height or ground monitoring equipment scenarios). * Path 2 corresponds to the setting of covering the monitoring area with the shortest path under the condition that the height of the monitoring platform can rise. * Path 3 corresponds to the setting of covering the monitoring area with the maximum circular area under the condition that the monitoring platform height cannot be raised. * Path 4 corresponds to the setting of covering the monitoring area with the maximum elliptical area under the condition that the height of the monitoring platform can rise. * Path 5 corresponds to only supplementing the displacement setting in the z-direction on the basis of Path 1 under the condition that the height of the monitoring platform can rise.