Aiming at the problem that radar is easy to be damaged when being attacked by HPM weapons， this paper theoretically analyzes the relationship between the farthest protection boundary to antenna gain and receiving front-end limiter’s capability， and compares the capability of reflector radar and active phased array radar against front door coupling attack from the perspective of spatial filtering. The analysis shows that only when the HPM weapon is near the main lobe range of the reflector radar antenna， its front door coupling attack effect is stronger than that of the active phased array radar； on the contrary， it is weaker than active phased array radar. Because the main beam of the reflector antenna radar is very narrow， the attack time window is very short， so the reflector antenna radar has stronger protection ability when facing HPM weapons.

An improved unmanned aerial vehicle （UAV） low altitude penetration model based on safe flight space is presented to solve the problem of lack of combination with the characteristics of UAV after terrain preprocessing. A safe flight space is constructed to reduce terrain constraints and ensure the safe flight of UAV in low altitude penetration. The trajectory planning model is improved by combining with the characteristics of UAV to increase the stability of UAV flight process and the smoothness of planned trajectory. The particle swarm optimization （PSO） algorithm is used to simulate the two models before and after the improvement in complex elevation map to verify the rationality and effectiveness of the improved model.

The analysis of radar fault cause text is helpful to locate the fault location， facilitate equipment maintenance and analyze equipment performance. Knowledge extraction， representation and management of radar fault cause text using knowledge graph technology can effectively improve the utilization efficiency of the text， quickly locate the fault location and analyze the equipment performance in time. On the basis of summarizing the characteristics of radar equipment fault cause text， radar equipment fault cause knowledge graph is constructed by a method combines both the scheme layer and the data layer. The scheme layer of the knowledge graph in the top-down style is designed， which defines the knowledge framework， the concept types， and the relationships between the concepts of the knowledge graph. For the text characteristics， the data layer of knowledge map is constructed in the bottom-up style： in order to solve the problems of small sample size and compound words entity recognition， entity naming recognition is carried out by Att-AlBERT-BiGRU-CRF model. The ALBERT-BiGRU-Att model is used for relationship extraction. Experiments show the effectiveness of the above extraction method. Based on the entities and relationship， the knowledge graph of radar fault causes is constructed.

With the advances in reconnaissance and reconnaissance-strike integrated technology， the transparency of the battlefield in modern warfare is increasing. The survival of military targets faces serious threats， and camouflage protection is an important prerequisite to ensure the survival on the battlefield. The inception， emergence， development and maturing of camouflage technology applications are reviewed； summarizes the research status of certain camouflage technologies such as stealth， sheltering， disruptive pattern-making， and faking. The analysis suggests that future camouflage technologies may incorporate multispectral compatibility， intelligent adaptation， and integrated designs. The paper provides important and valuable references to the R&D of military target camouflage technologies.