# Intelligent Simulation Technology Based on RCS Imaging
## 3 Target Simulation Modeling and Analysis  
An aircraft's RCS is mainly composed of three parts: sharp angle RCS distribution characteristics, stationary spatial distribution region, and some fluctuations caused by multiple scattering. It becomes very complicated to directly simulate the entire horizontal \(360^{\circ}\) space region of an aircraft. Therefore, the typical characteristics of the aircraft's horizontal position, including nose, wing and tail, are described in the following. The design of these three parts can help to effectively realize the target drone simulation [29].  
(1) Nose \(-30^{\circ}\)\(\sim\)\(30^{\circ}\) scheme design.  
The nose simulation assembly is mainly composed of a \(60^{\circ}\) variable corner reflector and two Luneberg lens reflectors, wherein the vertical side length of the corner reflector is \(600\) mm and the diameter of the Luneberg lens is \(83\) mm. The scanning angle range is as follows: azimuth dimension \(-90^{\circ}\)-\(90^{\circ}\), pitch dimension \(0^{\circ}\), angular scanning interval \(1^{\circ}\). Figures 7 and 8 show the composite simulation model and the RCS distribution characteristics, respectively.  
As Figure 8 shows, the RCS distribution characteristics of the assembly have an error of about \(0.3\) dBsm at the maximum RCS of \(0\) degrees compared with the distribution characteristics of the head, which meets the requirements. Meanwhile, the sharp angle range of \(-3^{\circ}\)\(\sim\)\(3^{\circ}\) is also consistent, which fulfills the design requirements.  
\begin{table}
\begin{tabular}{c c} \hline
**Fidelity Score** & **Parameter Indicator** \\ \hline
90–100 & Most realistic \\
80–90 & Very realistic \\
70–80 & More realistic \\
60–70 & General fidelity \\ Less than 60 & Unreal \\ \hline \end{tabular}
\end{table}
Table 1: Fidelity evaluation index.  
Figure 7: Head combination simulation model.  
(2) Wing \(-30^{\circ}\)\(\sim\)\(30^{\circ}\) scheme design.  
The wing assembly is mainly composed of a tetrahedral variant assembly with a side length of 780 mm and two metal balls with a diameter of 192 mm. These balls are mainly used to reduce the edge diffraction of the corner reflector. The scanning angle range is as follows: azimuth dimension \(-90^{\circ}\)\(\sim\)\(90^{\circ}\), pitch dimension \(0^{\circ}\), angle scanning interval \(1^{\circ}\). Figures 9 and 10 show the composite simulation model and the RCS distribution characteristics, respectively.  
As Figure 10 shows, the RCS distribution characteristics of the assembly have an error of about 0.02 dBm at the maximum RCS of \(0^{\circ}\) compared with the distribution characteristics of the head, which meets the requirements. Meanwhile, the sharp angle range of \(-3^{\circ}\)\(\sim\)\(3^{\circ}\) is also consistent.  
Figure 8: Comparison results from \(-30^{\circ}\) to \(30^{\circ}\) of aircraft’s head and head combination.  
Figure 9: Wing combination simulation model.  
(3) Tail \(-30^{\circ}\)-\(30^{\circ}\) scheme design.  
The tail simulation assembly consists of a \(60^{\circ}\) variable corner reflector, a Lombo ball reflector and two metal balls. The vertical side length of the corner reflector is 540 mm, and the diameter of the Lombo ball is 83 mm. The scanning angle range is as follows: azimuth dimension \(-90^{\circ}\)-\(90^{\circ}\), pitch dimension \(0^{\circ}\), angle scanning interval \(1^{\circ}\). Figures 11 and 12 show the composite simulation model and the RCS distribution characteristics, respectively.  
As Figure 12 shows, the RCS distribution characteristics of the assembly have an error of about 0.05 dBsm at the maximum RCS of \(0^{\circ}\) compared with the distribution characteristics of the head, which fulfills the requirements. Meanwhile, the sharp angle range of \(-3^{\circ}\)-\(3^{\circ}\) is also consistent.  
Figure 11: Tail combination simulation model.  
Figure 10: Comparison results from \(-30^{\circ}\) to \(30^{\circ}\) of aircraft’s wing and wing combination.