In aero anti-submarine warfare,submarine is always in an unfavorable condition.It is very important to improve the engagement capability of submarine against antisubmarine plane.This paper analyses two methods of submarine localization on sonobuoys array using towed integration buoy or ESM: the method of mono-static two point direction finding location and the method using bearing rate of change.The effect on localization error of submarine's bearing,bearing rate of change and velocity is also analysised.A model of submarine estimating sonobuoys array's localization is established,and then an evasion strategy of submarine to break through sonobuoys array is proposed.The result shows that submarine can localize sonobuoys array,which can offer reference to submarine in ASW.

在航空反潜战中,合理有效地布放被动浮标阵是提高探测概率的关键.该文将遗传算法应用于优化被动浮标布阵,合理设计了交叉算子,变异算子和适应度函数等.仿真分析了按经验布放的传统浮标阵和GA优化阵形的探测效能,结果表明该算法在复杂水声环境条件下,能有效提高被动浮标阵的探测概率.

According to the course of airdropped lighted torpedo to attack submarine,the models of noise jammer,self-propelled acoustical decoy,torpedo and submarine in acoustical warfare were built.Furthermore a typical anti-torpedo counterplan was discussed.On this basis,a novel counterplan was brought forward,that is,to use two self-propelled acoustical decoys to seduce the torpedo to run after.Simulations were made to analyze the effect of the release time and course of the second decoy,and that of submarine＇s second evasion on submarine＇s survivability probability.The simulation results show that the novel counterplan can improve the countermeasure efficiency significantly.It is of practical guiding significance for submarine to properly use countermeasure equipments to fight against the torpedo.

When a torpedo is coming towards a submarine,the vessel has to properly maneuver and in the mean time using countermeasure equipment to achieve the optimal defensive position.In relation to the study of anti-torpedo defense,a typical anti-torpedo counterplan was studied,the movement and detection models in a countermeasure course were built,and on this basis a novel counterplan was optimized by a genetic algorithm.The algorithms were then designed,and lastly simulations were conducted.The comparison results show that the optimized counterplan can improve a submarine's survival probability by 10%,which is vital for submarines in anti-torpedo defense.

When a torpedo is coming towards a submarine,it may launch mobile acoustic decoy to improve defence effect.According to the countermeasure procedure of submarine launching mobile acoustic decoy to fight against the torpedo,optimized trajectory model of mobile acoustic decoy,maneuver evasion model of submarine,search and attack trajectory model of torpedo and acoustic detection models in countermeasure course were built,and on this basis the parameters of direct sailing turn-corner trajectory of mobile acoustic decoy on submarine's survival probability were simulated and analyzed.The results show that by properly designed direct sailing distance and turn angle it can improve submarine's survival probability obviously.

To solve the problem that the countermeasure effectiveness of submarine defending against the torpedo can only be analyzed qualitatively and not quantitatively,the quantitative models for analyzing the countermeasure effectiveness of anti-torpedo solution is proposed,including the model of submarine evasion,the model of noise jammer,the model of acoustical decoy,and the model of torpedo search and attack.Monte-Carlo simulations show that,the model is capable to evaluate the countermeasure effectiveness of anti-torpedo solution of submarine quantitatively and is consistent with the qualitative analysis result.

根据空投轻型鱼雷反潜的工作过程,对潜艇使用噪声干扰器对抗鱼雷的作战效能进行了仿真研究。建立了水声对抗过程中噪声干扰器、鱼雷、潜艇的对抗模型,讨论了主动声自导鱼雷的探测模型和噪声干扰器的声对抗模型,并进行了仿真,得到了鱼雷可能再次发现目标时的时间节点。结果表明:噪声干扰器的合理使用和潜艇的快速反应可显著降低鱼雷对潜艇的探测性能,这为潜艇指挥员正确使用噪声干扰器、取得好的鱼雷对抗效果提供了参考依据。

This paper researched models of helicopter searching submarine in spiral curve and dipped sonar detecting targets,and also studied the mathematical models of submarine evasion.Basing on the models,it discussed the effects of different speeds and evasion strategies on searching probability of dipped sonar.Lastly simulation results show that searching probability of dipped sonar decreases with the increase of submarine's speed,and that the effect on the searching probability of dipped sonar in active mode is also larger than that in passive mode,and that when submarine evades with full speed far away from the current dipped point the searching probability will be reduced obviously. It is of practical guiding significance for submarine fighting against dipped sonar.

According to the background of helicopter searching submarine,the mathematical models of dipped sonar searching submarine in active mode was built. The effect of thermocline on the submarine stealthiness was then discussed,and the simulations were also made. The results showed that thermocline has an important effect on submarine stealthiness. It is of practical guiding significance for submarine to use underwater environment to improve its stealthiness in acoustical warfare.

According to the course of active sonobuoy searching submarine,the effects of submarine evasion on combat effectiveness of active sonobuoy is studied.The mathematical models of active sonobuoy detecting targets are established.According to the theory of smooth averaged sound field in shallow water,the searching scope of active sonobuoy is deduced when the depth of submarine is changed.Basing on the presented models,the searching scope and detection probability of active sonobuoy are estimated,and the effects of different evasion angles,depth and sea environment on searching submarine are amalyzed.Lastly simulation results show that under certain condition the combat effectiveness of active sonobuoy for submarine can be reduced by proper evasion strategy.

Warning and detecting artisubmarine aircraft by submarine is studied. Aiming at the information dissymmetry in the rivalry between submarine and antisubmarine aircraft, Doppler-Shift Frequency effect and underwater acoustic propagation from aircraft are modeled. The underwater detection method of air acoustic source is proposed. And, the problem about how to enhance acoustic early-warning ability of submarine against antisubmarine aircraft is discussed, which has guiding signigicance for changing dissymmetry in countermeasure.

An airborne vision recording and replaying system has been developed.It uses MPEG-2 compression standard to compress the video and audio data,and prolongs the recording time greatly.By channel selection it can record the data from different sensors;by software control it can easily manage the recorded data(such as download,delete,replay).Dynamic procedure of instruments and sounds in the aircraft cockpit and operations of the pilot all can be truly recorded by the developed system.By downloading and replaying,it can recur the scene in the air completely.Thus it can supply reliable references for evaluating flight,improving flying qualities and reforming maintenance service capability.From performance test and practical experiments,it is proved that the system reaches the standard of the design function and satisfied the demands of performance index.Nowadays the system has been also equipped in the army.This paper mainly discusses the system scheme,hardware structure and software flows.

According to the tactical background that submarines use thermocline to escape active sonar,the effect of thermocline on active sonar searching submarine was studied.The mathematical models were built firstly;and according to smooth averaged sound field in shallow water the transmission loss was given out.On these bases,the detection probability of active sonar was then deduced.The effects of thermocline's depth,thickness and sound velocity change on searching submarine probability were discussed,and lastly simulations were made.The research results show that thermocline has an important effect on the searching submarine effectiveness of active sonar.It is of practical guiding significance in antisubmarine battles and training.

潜艇辐射噪声的声源级大小会直接影响潜艇的隐蔽性,潜艇的辐射噪声与航速密切相关.分析了目前主要模型的不足,在此基础上对其中一个模型进行了改进.新模型考虑了临界航速的影响,兼顾了不同潜艇类型噪声大小差别较大的特点.仿真结果表明:该模型更好地符合潜艇噪声随航速变化的实际情况,更具有普遍适用性.

The hard-kill technology in acoustic warfare is capable of destroying the coming torpedo directly, and avoiding the second research and attack of the torpedo, to eliminate the dangers to our navy vessels. It is also one of the main developing trends in acoustic warfare. This paper introduces the presently main hard-kill countermeasure equipments, and then analyses their performance and characters, and lastly discusses their key techniques.

According to the designed characteristics and demands of aeronautic image compression system, lifting scheme wavelet and SPIHT algorithm was selected as the key part of software implementation, which was introduced with details. In order to improve execution efficiency, border processing was simplified reasonably and SPIHT (Set Partitioning in Hierarchical Trees) algorithm was also modified partly. The results showed that the selected scheme has a 0.4dB improvement in PSNR(peak-peak-ratio) compared with classical Shaprio's scheme. To improve the operating speed, the hardware system was then designed based on DSP and many optimization measures were then applied successfully. Practical test showed that the system can meet the real-time demand with good quality of reconstruct image, which has been used in an aeronautic image compression system practically.

Radial acceleration of radar target is characteristic of relative motion between radar and target, and is significant for maneuvering target recognition and tracking. To estimate radial acceleration from radar echo, fractional Fourier transformation (FRFT) was used in this paper. The acceleration estimation formula was deduced firstly, and then its estimation flow was given out. Differences in antinoise interference capability between FRFT, WVD-HT (Wigner-Ville distribution and Hough transformation) and WVD (Wigner-Ville distribution) in estimating chirp signal parameters were analyzed. Then the relation between acceleration measurement accuracy and angle search step was deduced, and lastly simulations were made, proving that the method can improve operational speed, control operational precision and be also of better antinoise interference capability than other methods.

When a radar works in the pulse mode,the traditional methods for Doppler information extracting need multiple pulse echoes to extract Doppler.To solve this problem,a new method is proposed to extract Doppler information based on single pulse echo. The wavelet transformation is used to process the possible envelope aberrance in practical situation.Simulations are lastly conducted to show the feasibility and effectiveness of the method.

An airborne vision recording and replaying system has been developed to satisfy the military needs. It used MPEG-2 compression standard to compress the video and audio data, and prolonged the recording time greatly. By channel selection it can record the data from different sensors; by software control it can easily manage the recorded data (such as download, delete, replay and etc). Dynamic procedure of instruments and sounds in the aircraft cockpit and operations of the pilot were all able to be truly recorded by the designed system. By downloading and replaying, it can recur the scene in the air completely. Thus it can supply reliable references for evaluating flight, improving flying qualities and increasing maintenance service capability. From performance test and practical experiments, it has been proved that the system reached the standard of the design function and satisfied the demands of performance index. Nowadays the system has been also equipped in the army. This paper mainly discusses the system scheme, hardware structure and software flow.

This paper discusses the distribution characteristic of the Wigner-Ville crossing item and deduces relation of the position from crossing items and itself in Time-Frequency, and the method has been given that identified crossing items from distribute the characteristic and adding identify the signal. Finally the simulation experiment is done.