In view of the large uncertainty and subjectivity in evaluating the toughness of ship power system， a method of FAHP-CM for evaluating the toughness of ship power system is proposed by combining cloud model （CM） and fuzzy analytic hierarchy process （FAHP） on the basis of establishing the evaluation index system of ship power system. The method uses FAHP-CM to calculate the weights of evaluation indicators， which makes the weights more objective and accurate， simplifies the calculation process and improves the evaluation efficiency. The results of example analysis show that the proposed evaluation method can reflect the toughness of ship power system well， and can effectively solve the evaluation uncertainty and subjectivity problems， so that the evaluation results are more scientific and reasonable.

The number of space targets in the LEO region is increasing， and the spacecraft orbital maneuvers are getting stronger and stronger. Combined with the demand for computational efficiency and accuracy of fast collision warning for LEO maneuvering targets， this paper proposes a short-term state error propagation method based on the state transfer tensor under the assumption of J2 model. The method introduces the second-order state transfer tensor to describe the nonlinear characteristics of error propagation from the perspective of spacecraft relative motion， gives the approximate analytical expression of error propagation， and completes the collision probability calculation on this basis. The simulation results show that the method proposed in the paper has good computational efficiency and accuracy for the short-term error propagation and collision probability calculation of LEO targets.

In view of the fact that some active precision-guided munitions in the world mainly use anti-photoelectric infrared jamming agents for effective countermeasures， the jamming principle and research progress of the main components of materials used for multi-spectrum jamming agents， such as copper powder， metal chaff， expanded graphite， graphene and carbon fiber， are introduced. On this basis， the research progress of three realization methods of multi-spectrum jamming agents is reviewed. The limitations of current research on combination charging technology， composite dispensing technology and material modification technology are analyzed. Focusing on the strong structural design characteristics of new materials， the research and development can effectively overcome the inherent contradictions and shortcomings of existing multi-spectrum realization technology， and the development prospect of multi-spectrum jamming agents is prospected.

To improve the low-elevation detection performance of ship-borne phased array radar， the low angle multi-path model， sea surface reflection model and elevation estimation model of phased array radar （PAR） are established. The relationship between low-elevation angle accuracy of ship-borne PAR and angle estimation method， radar frequency， beam direction， sea state and beam width is systematically analyzed through simulation. The results show that sum-sum angle estimation method， lower beam width by improved beam weight， higher beam direction of angle estimation sum beam， multi-frequency smoothing are benefit for low-elevation angle accuracy improvement. A low-elevation angle estimation method which takes advantage of all the factors above is proposed， which has achieved excellent real-world application results and significant engineering practical prospects.

In war， early warning and detection system as a typical complex system， the effective evaluation of its detection effectiveness has always been an important practical problem that needs to be studied and solved. The limitations of traditional effectiveness evaluation methods are break- throughed. On the basis of analyzing the basic principles of knowledge graph technology and Bayesian evaluation method， a new method of detection efficiency evaluation of early warning detection system based on their comprehensive application is proposed. The knowledge graph is constructed by using expert knowledge and experimental data， and the Bayesian network method is further used to implement knowledge reasoning， so as to realize the evaluation of system detection efficiency. The effectiveness of the proposed method by constructing specific combat scenarios is verified， and the evaluation of the proposed method based on deduced data is analyzed.