# Adaptive Satellite Navigation Anti-Interference Algorithm Based on Inverse Cosine Function
## 4 Simulation Analysis
### Navigation Interference Suppression Effect Analysis
#### 4.2.2 Experimental Verification of Interference Suppression Performance  
To verify the suppression effect of the algorithm on navigation interference signals, the algorithm anti-interference performance verification hardware system structure is shown in Figure 8, mainly using the satellite navigation signal simulator to generate normal satellite navigation signals and the vector signal generator to generate interference signals through the combiner into the IF signal collector, where the collected IF signal is subjected to a series of operations, such as capture, tracking, positioning, and decoding, after the anti-interference algorithm in the software receiver [42]. The signal source is the NSS8900 simulation source of Hunan Satellite Navigation Company (Changsha, China), and the  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Interference** & **LVS-LMS** & **VVS-LMS** & **NDVS-LMS** & **ICVS-LMS** \\
**Signals** & **Algorithm** & **Algorithm** & **Algorithm** & **Algorithm** \\ \hline Interference1 & 38.86\% & 37.99\% & 38.77\% & 46.40\% \\ Interference2 & 57.98\% & 58.71\% & 60.19\% & 69.13\% \\ Interference3 & 63.88\% & 65.09\% & 67.15\% & 76.10\% \\ \hline \end{tabular}
\end{table}
Table 2: Comparison of interference suppression performance of the four algorithms.  
Figure 7: Interference signal amplitude comparison diagram.  
interference source is the SMBV100 A Vector Signal Generator produced by Rohde & Schwarz Company (Munich, Germany).  
The satellite capture results serve as a more intuitive indicator to assess the algorithm's effectiveness in mitigating and suppressing interference signals. In the simulation experiments, the SNR of the navigation signal is deliberately set to \(-20\) dB. Figure 9 illustrates the acquisition outcomes of four distinct algorithms after they have processed the signals received by the receiver. The orange peak represents the acquisition peak of the navigation signal.  
The simulation results in Figure 9 reveal a distinct peak in the satellite capture outcome from this algorithm. The adjacent interference peaks have been effectively suppressed, minimizing their impact on the navigation signal. This reduction in interference during capture safeguards against potential disruptions to the target signal, ensuring the receiver's accurate capture of the navigation signal and decoding of precise navigation information.  
The Figure 9b-d show that the existing algorithm is less effective in suppressing interference when capturing satellite signals, and although there are peaks in the navigation signal, there are more interference peaks in the surrounding area, which can easily interfere with the target navigation signal in the process of capturing, thus, resulting in false capture and affecting the subsequent tracking and positioning solution. It shows that the proposed ICVS-LMS algorithm has a more effective interference suppression ability.  
Figure 8: Algorithm anti-interference performance verification hardware system structure.