# Intelligent Target Design Based on Complex Target Simulation
## 1 Introduction  
International warfare has gradually developed from a backward pure weapon combat method to a systematic and information-based intelligent combat system. Therefore, it is very important in this era to improve a country's scientific and technological levels and strengths relating to national defense. In modern radar electronic warfare, the position and role of a radar in electronic communication warfare are particularly prominent. The radar technology has seen very rapid development until now. A variety of anti-jamming and anti-radiation missile technologies are applied in modern radar systems. This is a very beneficial development for the radar system itself. However, it is a huge threat for military operations and national defense security. At the same time, new radar systems and technologies have emerged and developed rapidly, increasing the prominence of the role of passive interference in information electronic warfare. Passive jamming [1] is an important field in the current anti-radar technology and it is widely used. The passive reflectors, which are often called the passive echo enhancers, are important simulated targets in military exercises. Due to the high cost of military equipment, passive radar targets are often used [2] to simulate the radar cross-section (RCS) of actual objects or equipment as well as their maneuvering characteristics in order to meet the needs of daily military training. A passive radar target mainly refers to the target or device with specific requirements of RCS spatial distribution and maneuvering characteristics, such that the incident radar wave is concentrated within a certain spatial angle range and reflected back according to the direction of the incident radar wave. At present, the highest reflection is used forscaling. The structure of the reflector used for the passive radar target can include a ball, Luneburg ball, trihedral corner reflector, or their combination. Passive false targets made with trihedral reflectors can serve as low-cost simulated targets during self-training [3, 4] for sensitivity testing of radar systems. Trihedral reflectors are used as camouflage [5], whereby the actual equipment being simulated is covered with a bigger RCS. A Luneburg ball is also called a Luneburg lens [6, 7, 8, 9]. Its outstanding features include a high RCS value and a wide coverage angle of secondary radiation direction. It is mostly used as stealth material against radars in military fighter jets or military ships. For example, the American F-22 and F-35 stealth fighters use Luneburg balls as radar scatterers. The University of Electronic Science and Technology of China [10] carried out related optimization research on the layered design of Luneburg balls for Ku, Ka, and other frequency bands. The National University of Defense Technology [11] designed and optimized a compressed all-dielectric plane Luneburg lens antenna using optical transformation and analyzed its multi-beam performance. The existing local and international application technology for simulated targets is relatively mature. Usually, a single corner reflector or an array of multiple corner reflectors is used for simulation. It is sufficient to have strong reflection states at different angles, but corner reflector is only used to simulate objects with a relatively simple structure. Objects with relatively simple shapes are used to simulate the RCS spatial distribution characteristics of the discovery direction, as carried out in [12]. The radar station antenna simulates its radiation pattern [13]; however, the RCS value of a single angle inversion can simulate the RCS of the radar antenna station. Nevertheless, the RCS of the radar antenna station distribution characteristics is considerably larger than the main beam range of the radar antenna station. Detection and identification techniques tend to focus on saliency, i.e., global rarity or local contrast.