The problem of how to design the multi-UAV formation autonomous reconfiguration is studied. Based on three kinds of cost functions,the nonlinear dynamic equations of UAVs and four inequality constrain conditions,a nonlinear multi-objective optimization model is constructed. After applying weighted sum method and separating all equality constraints from inequality constraints,the former nonlinear multi-objective optimization model is converted into a standard nonlinear single-objective optimization model. Then the interior point algorithm from operations research is used to solve the optimization problem. To avoid rank deficiency,some improvements are made in realizing the interior point algorithm. The equivalence property between multi-objective optimization through weighted sum method and single-objective optimization is proved. Finally,the efficiency of the proposed strategy is confirmed by the simulation results.

In order to improve the survival probability of missiles in attacking process,the trajectory of it should be designed properly.Based on the monopulse radar performance indexes,the RCS values of a cone-spheroid shaped warhead are calculated out by using electromagnetic computing software.And detection probabilities of the warhead at different launch angles and different altitudes are computed out respectively.Numerical simulation results show that there are two areas where detection probability stays at a high level.One is that the launch angle is in the range of 0°~90°,while warhead altitude locates in 20~60 km;the other is launch angel is in the range of 270°~360° while warhead altitude locates in 20~60 km.The detection probability keeps at al low level when the launch angle is in the range of 90° to 270°.It comes to us that launch angle of missile should be selected carefully to keep the detection probability stay at a lower level.

The continuous deepening of the application of UAVs in all fields raises higher requirements to the autonomy of the UAVs.Through the simulation to human emotion decision-making process,we established a decision-making method based on emotional intelligence,and used it in the decision-making problems of UAV path planning and threat avoidance.The simulation results show that the method of decision-making based on emotional intelligence has better effect than the traditional method.

According to the operation characteristics of the airdrop torpedo,three factors that have great effects on detection probability of the airdrop torpedo are studied in detail,including torpedo searching area,entry point dispersion and submarine dispersion.The interactions among the factors are also analyzed.Probability theory is used for constructing the analytical models of the detection probability respectively under accurate information source and fuzzy information source.The experimental results show that the calculation result of the analytical method is highly consistent with the result of the simulation method.

In view of the problems that increasing the sample number will reduce system attitude updating frequency and bring large coning error,while enhancing sampling frequency will increase the burden of navigation computer hardware,we proposed a modified conic error compensation algorithm.The angle increment information of the first two cycles' gyro output and the gyro sampling values of the current moment are used for coning error compensation by means of superimposed sampling,and the compensation factors are obtained according to the principle of minimum error.The algorithm not only improves system attitude updating frequency,but also reduces the coning error caused by equivalent rotation vector method.Therefore,the precision of attitude algorithm is improved.

Aiming at altitude-keeping of a tilt tri-rotor UAV in flight mode conversion,a new transition strategy was proposed,by which the UAV could implement the transition directly from hovering state without requiring an initial velocity.The Newton-Euler method was adopted for dynamics modeling of the transition mode.The relationship between tilting angle and flight speed,i.e.,the corridor curve of transition mode,was obtained according to the model analysis.Flight test was made to two different tilting modes by using the experimental prototype of tilt tri-rotor UAV.Analysis to the telemetering data obtained from ground station shows that the corridor curve of transition mode is effective for altitude-keeping.

The UAVs need to avoid the dynamic threat effectively while encountering it in the flight airspace.For solving problem of the cooperated UAVs' autonomous avoidance of dynamic threats,a cooperative parameter is introduced into collision avoidance strategy,and the optimization theory is used for computing the optimum collision avoidance strategy.Therefore,it can realize effective avoidance to multiple types of dynamic threats.Simulation result demonstrates that the method can implement the cooperated UAVs' real-time evading from dynamic threats.

To realize fast satellite selection for GPS/BD integrated navigation system,a selection algorithm based on the geometry layout is presented.According to the geometry layout feature of the optimal satellite selection result,the visible satellites are divided into different groups by their azimuth and elevation,and then cost function is used for selecting satellites in each group.Compared with the original optimum satellite selection algorithm,the fast satellite selection algorithm need less computation.The emulation result shows that it works well and can keep the Geometric Dilution of Precision (GDOP) within 2.5.It can satisfy the requirements to precision and real-time performance in the aerospace field.

Weapon-Target Assignment for attacking ground targets (BTG-WTA) is an important issue in modern warfare,which has larger scale and is more complicated than the ordinary weapon-target assignment.Particle Swarm Optimization (PSO) algorithm is used for solution of the BTG-WTA.The key issues,such as particle initialization and inertia weight selection,are improved for adaptable to BTG-WTA model,and simulation is made to an example.The results of simulated experiment indicate that PSO is more efficient than the classical algorithm for BTG-WTA,and thus has great application value.

A target tracking method based on BRISK feature matching and CamShift is proposed under the framework of CamShift target tracking.In this method,both the color features and local features are used to locate the targets for realizing accurate target tracking.Compared with traditional CamShift,this method can keep the real-time performance,while improving the sensitivity to the changes of background,dimensions,rotating and shading,and the oneness of the characteristics of the target tracking.The contrast experimental results show that: 1) The tracking method proposed is faster than the method based only on the feature matching; 2) Compared with CamShift,it has higher robustness to the changes of background,dimensions,rotating and shading; and 3) The precision of tracking is improved.

This paper focuses on the attitude tracking control problem of spacecraft formation flying under unmeasured angular velocity and saturation input.By combining the unknown saturation effect with the external disturbance into a compounded disturbance,a novel finite-time observer was designed to estimate the angular velocity and compounded disturbance.Based on which,a finite-time sliding-mode cooperative control protocol was proposed.The stability of the system was verified theoretically by constructing an appropriate Lyapunov function.Simulation result shows that the method can implement accurate estimation and cooperative control to the attitude in limited time.

In order to solve the ambiguous acquiring problem for Binary Offset Carrier (BOC) modulated signals caused by multiple peaks of its autocorrelation function,we put forward a new acquisition algorithm based on combined correlation functions for BOC(n,n) signals through analyzing the autocorrelation function of the BOC modulated signal and the existing acquisition algorithms,and by use of the traditional acquisition algorithm of parallel code phase search acquisition.The algorithm is realized by adopting the autocorrelation of BOC(n,n) signal and cross-correlation of BOC(n,n) with Pseudo Random Noise(PRN) code,and through the operations of shifting ±Tc/2,summing,modulus and squaring.The theoretic analysis and simulation results show that:The proposed algorithm can remove the related side-peak,significantly improve the main-peak value and keep the autocorrelation peak width,while having an ideal acquisition performance,less computation cost,and is easy to implement.

Due to the complexity of the airborne system,it is difficult to implement exhaustive testing.To assure the system airworthiness,relevant sets of standards have been issued by SAE and RTCA,defining the development process.However,the standards are established in the way of “what” rather than “how”.Consequently,it requires the users to not only understand,but also formulate a localized procedure in order to apply these standards effectively.The airborne electronic system is a typical complex system,thus a localized procedure is needed for establishing the system airworthiness standard.This paper proposes a method to construct customized development process for the airborne electronic systems.The method considers both management requirements and engineering approach to target an integrated,flexible and efficient process.

When tracking noisy signals with traditional adaptive tracking differentiator,disturbance may be introduced into rate factor and filtering factor of the differentiator and leads to disorder and tracking to the noise.To solve this problem,the cause of noise was analyzed,performances of adaptive tracking differentiators were studied,and an Improved Adaptive Tracking Differentiator (IATD) was proposed.By using the adaptation function taking the Moving Window Standard Deviation (MWSD) estimation of track spacing as input,the IATD could adjust the rate factor and filtering factor optimally.Simulation indicates that IATD can adjust factors more accurately and rapidly with noisy input,and has better noise restraining ability in wide range of signal noise ratio.

Different solutions of maintenance and operation should be taken for equipment at different health levels.The current testing and evaluation of equipment is still realized by the “true or false” method,which can only describe whether the equipment is normal or not,and the health level can't be evaluated.Aiming at this problem,a health status assessment method based on improved evidence theory is proposed,taking a certain type of servo mechanism as the research object.Firstly,a set of parameters is proposed to represent the health of the servo mechanism comprehensively,and a normalization method is used to process the test data.Furthermore,the membership of each processed parameter is fused based on the improved evidence theory,and thus the health status level of the servo mechanism is obtained.Finally,the proposed method is verified by the case study to a certain servo mechanism.It is demonstrated that the proposed method is valid,with certain application value.

The influence of atmospheric transmission and object reflection on polarization properties of circularly polarized laser beam was studied.Based on the Monte Carlo method and with Stokes-Mueller matrix form,we used Mie scattering theory and polarized bidirectional reflection function model to trace the polarization state of each photon,made statistics and analysis to Stokes vector and polarization information of the final polarized light.The result of simulation shows that:With visibility of 23 km,distance of 100 km,target refractive index of 1.44+5.23i and surface roughness of 0.1 mm,the atmosphere has less influence on the polarization properties,while the target reflection has greater influence on the polarization properties;and the circular polarized light turns into elliptical polarized light at the receiving end.

Aiming at node deployment optimization in wireless sensor networks,an effective chaotic glowworm swarm optimization was proposed.On the premise that connectivity among nodes was guaranteed,we established a mathematical model to achieve the coverage of objective area with wireless sensor networks,and transformed the node-deployment optimization problem into finding the largest value of a function.The glowworm swarm optimization with the strong search performance was used to search the optimal node deployment.And the cubic mapping chaotic operator was introduced to enhance the ability of local search and robustness and to keep the diversity of population.Then,the proposed algorithm was verified through the numerical benchmark functions and coverage simulation.All the results showed that the proposed algorithm has the ability to jump out of local optimum and has good optimization results,nice stability and strong robustness.Hence,it can satisfy the requirement of optimal node deployment in wireless sensor networks.

The reconfigurability metric standard of control moment gyro of satellite actuator was studied,and a reconfigurability metric standard under energy consumption constraint was proposed.Based on the satellite attitude control dynamics equation and kinematic equation,a linear dynamics equation was established in the form of state space.Failure fault factor vector was introduced into the linear dynamic equation.The reconfigurability metric standard was established based on Gram matrix.Finally,simulation was made for control moment gyro group with pyramid configuration,and the result show that this method is correct and effective.

A large F/number (F/#) cooled infrared optical system based on warm diaphragm was designed.The influences of thermal radiation of the warm diaphragm itself,the external environment stray radiation and the narcissus reflection on the system performance were eliminated by optimizing the design parameters of the warm diaphragm.The system achieved the design requirements of high thermal imaging performance,long focal length and small volume.Performance tests and imaging results show that:the reflective warm diaphragm will not bring significant change to the performance of the system through reasonable optimization design,which verifies the correctness and feasibility of the design method.

Nodes moving with high speed can bring rapid topology change in tactical communication network,which may invoke new route discovery processes and lead to network performance degradation.To alleviate this problem,a novel Stable Wrapped Multi-path Routing (SWMR) protocol is proposed,which uses source routing approach to establish node-disjoint primary routes,and builds up several backup paths among each primary route synchronously by utilizing overheard route reply packets.By constructing such multi-path routes,the protocol not only provides higher network stability,but also reduces route discovery latency and routing overheads.Simulation results show that:compared with AOMDV and AODV,SWMR has a better routing performance in packet delivery ratio,average delay and normalized load metrics when the network topology changes rapidly.

It is usually difficult to design and manufacture the gratings of single plate with single reflecting surface,thus we proposed a two-dimensional,L-shaped extended configuration with single plate.This configuration consists of two specular reflecting surfaces and three holographic gratings with the same period and groove orientation,which makes gratings design and fabrication easier.According to the calculation and analysis to the optical path of configuration,the size of the turning grating is no larger than 40 mm×40 mm.The simulation result demonstrates that the display configuration is reasonable and correct,and can realize the display effect with 30°×30° field of view and 30 mm large exit pupil.This configuration can be applied to an augmented reality display or a Head-Mounted Display (HMD).

A software security module is designed,which is an external hardware module,and can provide such functions as copyright authentication,kernel data encryption,stable operation monitoring and so on.The external module uses USB to connect with host PC,and a free driver portable data channel is achieved by taking the microcontroller of security module as a virtual USB mass storage device.A communication protocol is designed for use between the security module and PC based on packets layered communication protocol stack,and thus to implement safe and reliable data communication.The usage of the security module is illustrated by taking the software for cable ampacity analysis as an application example.

Based on the characteristics of time delay and frequency shift of linear frequency modulation radar,the traditional intermittent sampling jamming is improved,which makes up for the shortcomings of traditional methods in dealing with some new type of anti-interference modes. The improved method uses the product of time domain signals and signal delay conjugate,and false target position controlling model is given through theoretical derivation. It is found that position of false target is unrelated to the frequency modulation slope. So it is proved that the improved method is superior to the traditional method. Finally,the effectiveness of the improved method is verified through simulation experiment. The simulation analysis and discussion are carried out from two aspects of the interference power and the flexibility of the false target position setting. The results show that it would be better to determine firstly the number of extended order and then calculate the required delay,which can not only obtain a larger signal gain,but also more flexible in the false target setting.