A method for conflict detection of collision avoidance and assessment of collision threat levels are presented in this paper.The principle of collision avoidance was introduced firstly.In order to obtain an effective result different strategies for collision avoidance were established based respectively on heading control velocity control height control and the combination of heading and velocity.The models of multi-objective cost function and the methods of optimal decision-making for automatic collision avoidance were also established.The simulation results demonstrated the effectiveness and practicability of the proposed methods.

In order to improve the warship formations effectiveness on air defense early warning the ellipse forming principle was introduced and the ellipse plane of the air attack course was determined based on analysis to the counter-situation factors between friend and foe. Then a method for assessing the potential air threat to the warship formation was proposed by use of the analytic geometry approach. According to the information about the disposition of air assault forces the potential air assault direction sector and the interval of time can be assessed by the proposed method before air threats are formed. The application example and the simulation show the feasibility accuracy and validity of the methods.

The structural design and optimization method is directly relevant to the avionic system as well as the survivability expansibility and maintainability of the whole aircraft system.The design process is analyzed and the design steps are confirmed to construct system conveniently.A concept of the directed graph of system structure is proposed and the mathematical description is also presented based on directed graph theory.On this basis an optimization method is further introduced.The structural directed graph of the system structure is decomposed vertically and horizontally and a hierarchical association structure is set up for the system resources which may supply a theoretical basis for structural design.Finally an example demonstrates the effectiveness of the proposed method.

In order to implement rapid recognition of the moving attributes of offing remote target a fast recognition method based on T1R1 system of nearspace platform is put forward.The method can be used to judge the moving attributes of the target only according to the statistic characteristics of Time Difference of Arrival (TDOA) values based on single receiver station without calculating the position of the target.Simulation results indicate the effectiveness of the method.

As a typical cooperative control problem tight sequencing arrival of multiple unmanned aerial vehicles (UAVs) has great potential significance for the UAVs in cooperative searching tracking attacking and evaluation.Laguerre diagram was introduced from computation geometry for path planning．When any two closest threats do not intersect the generated initial paths will pass through the interspaces between them.Velocity was periodically adjusted to improve the time precision of arrival.Simulation results show that the tight sequencing arrival of multiple UAVs can be realized with preferable robustness and precision by the proposed control method.

Accompanying escort antisubmarine with shipborne antisubmarine helicopter is an important method to ensure the security of surface ship formation.A new method of triangle search method was proposed according to the actual needs of flanking escort antisubmarine and the characteristics of antisubmarine helicopter when searching submarines with dipping sonar.The synchronization model was established and the synchronization between patrol searching line and the formation was realized effectively.The searching effectiveness of the triangle search method was simulated by using the simulation models established.The specific operational application of the model was optimized with the simulation result.This method can offer a theoretic foundation for the helicopter flanking escort antisubmarine operating application.

Research on risk propagation is an important direction of information system security risk evaluation.We redefined the original load of information system network and the concept of node breakdown/ failure based on risk propagation and risk propagation model as well as considering the mutual effect between the adjacent nodes.The local preferential redistribution rule of the load was proposed and the information system network node breakdown and the number of effective nodes were used to reflect the resisting ability of information system to risk propagation.Two attacking strategies deliberate attacking with known network information and random attacking without network information were designed.Information system security risk propagation under conditions of different node breakdown was analyzed through simulation.The results show that node breakdown caused by a deliberate attack is more likely to cause the rapid global propagation of information system security risk.

An aero tactical data link distributed simulation system was designed based on HLA/pRTI1516 and OPNET by combining HLA distributed simulation technology with OPNET network simulation platform. The problem that OPNET doesnt support HLA underlying software pRTI1516 was solved and OPNETs pRTI1516 communication interface was achieved. The data interaction between external simulation system and OPNET simulation platform was completed and the modeling and simulation of the physical node of the external system in the OPNET was implemented. Finally the performance of Link16 network protocol JTIDS was tested and the feasibility of the system was verified.

Bias registration is an essential process for correcting the system bias of sensors. In order to estimate the sensor system bias without cooperation targets a three-dimensional bias registration algorithm was proposed based on linear Kalman and least squares. This algorithm takes the curvature of the earth into account and can estimate the system bias of elevation angle that cant be calculated with the traditional 2D method. The system bias of sensors and the motion of target are combined into the same measurement equation by constructing a system model. Then the estimation of system bias is completed by using the linear Kalman and least squares. Simulation results show that system biases can be estimated effectively including elevation angle bias.

The nonlinear system recursive maximum likelihood (RML) estimation method was derived based on Unscented Kalman Filter (UKF) and real-time joint estimation of parameters and states for missiles with incomplete information was realized.First the guidance law was introduced into the missile state estimation model and a state filtering model was established.Then the classical RML method for parameter identification was presented based on which the nonlinear RML was developed through UKF.Finally the parallel calculation of parameter identification and state estimation was completed.The numerical simulation result shows that this method has fast convergence speed good real-time performance and high estimation accuracy.

A three-dimensional track initiation algorithm was proposed based on combinatorial Hough transform and traditional method to solve the problem about 3D radar track initiation. First the measurement data was projected on three planes then the combinatorial Hough transform was used to the points on three projection planes respectively. When the same point trail was initiated successfully in two projection planes at least after comparing the results on the three projection planes the straight-line track initiation was judged successfully. In the data processing, the real track initiation probability was increased using the three-step combination method and a plane kinematics speed was used to depress the combination number and reduce computational complexity greatly. Simulation in allusion to precise approaching radar data characteristic shows the effectiveness of this algorithm.

The establishment of an evaluating index system for C4ISR to realize system effectiveness evaluation is very important during in the whole life cycle of C4ISR construction.There are a lot of partitioning methods for the index system and their characteristics applicable ranges and conclusions are all different. In this paper three partitioning methods of ability oriented course oriented and quality oriented are analyzed.The advantages disadvantages and applicable ranges of each method are presented.An index system architecture of C4ISR is given by using the three methods synthetically.

The Head-Up Display (HUD) is an aviation product appeared in 1960s which is mainly used on the fighting aircrafts. Now it has been widely used in the automotive industry. Firstly the history and working principle of the automotive HUD are presented. Then the current situation and typical structures of automotive HUD technology are summarized. The future development of the technology is also described.

The relative advantages of fluxgate sensor applied to the geomagnetic navigation system were discussed by comparing its performance index with that of the commonly used magnetic sensors.The basic principle of the fluxgate sensor was analyzed.Then Nyquist sampling theorem was used to verify the feasibility of the fluxgate sensor applied to the subsonic low-altitude aircraft by spectrum analysis to the measured magnetic anomaly data in a county.A frequency response indicator was proposed for applying to the subsonic low-altitude aircraft i.e. when the response frequency of fluxgate sensor reach 40.8 Hz to 68.0 Hz it will be able to satisfy the response frequency requirements.

A model of image motion velocity vector was deduced based on vector calculation and coordinate transformation. This model is suitable for both airborne and spaceborne camera. The influence of attitude angle attitude angular velocity and ellipticity of the earth on the image motion was taken into account in the model and a digital simulation was completed. The results indicate that: 1) The image motion velocity increases with the velocity of aircraft and decreases with the height of aircraft for the airborne camera; 2) The ellipticity of the earth plays an important part for image motion of the spaceborne camera and the error caused in near-polar is up to 4.60%; and 3) The attitude parameters have greater influence on the spaceborne camera than on the airborne camera.

This paper presents a new approach of the Interacting Multiple Model (IMM) algorithm by introducing a non-linear guidance model from the guidance law.Unscented Kalman Filter (UKF) is applied to deal with the non-linear models in the IMM algorithm.Factor of Trajectory Convergence (FTC) is introduced based on the basic characteristic of the missile trajectory to adjust the transition probability online.The simulation results demonstrate that the guidance model based FTC adaptive IMM-UKF algorithm works perfectly in the tracking system.

Analysis is made to tracking and pointing accuracy requirements of the airborne laser weapons the control structure of the compound-axis is given and the error sources of tracking and pointing are concretely analyzed. The compound-axis servo-system was simulated with Matlab/Simulink. The simulation results show that: 1) the system has good dynamic performance high tracking accuracy and fine disturbance suppression effect; and 2) compound-axis of tracking and pointing of the airborne laser weapon is a quite effective control technology.

The principle of wave-gate tracking and the demand of adaptive wave-gate were introduced.The adaptive wave-gate tracking algorithm based on the Snake model was proposed according to the GVF Snake model in the active contour models and adaptive centroid tracking algorithm.Then the position and size of the wave-gate were ascertained on the basis of the convergence contour of the Snake model and the updating of the wave-gate was determined by the proportion of the background pixels in it.The experiment and simulation show that the algorithm can change the size of the wave-gate adaptively and track the target well.

The new generation air-to-air missile for short range dogfight has the characteristics of high maneuverability and high guidance precision which can be used as shipborad short range antimissile missile.A 3-DOF mathematical model of the vertical-launched missile was built up.In order to solve the problem of detection and guidance when a short range dogfight air-to-air missile is used to intercept anti-ship missile a practical guidance method was proposed.Using the target direction information a virtual target that moved on the detection line was introduced to guide the vertical-launched missile to fly to the target by the proportion guidance law.In approaching process the IR seeker could capture the weak and small infrared target stably and then change to the terminal guidance state in time.Finally an intercept simulation with the 3-DOF mathematical model illustrates the effectiveness of the guidance method.

The sidelobes of the planar antenna with multiple subarrays (MSPA) are caused due to its dispersed aperture.This paper analyzes the factors of peak sidelobes level forming for the antenna at different elevation angles and proposes some suppression methods.In order to reduce the peak sidelobe level of the MSPA in the working range the effect of the antenna aperture element directivity and amplitude attenuation are studied by using genetic algorithm and the peak sidelobe optimization is realized.The simulation results show that the integration of the MSPA orientation diagram needs only to consider the minimum subarray spacing constraint.Furthermore the element directivity and amplitude attenuation should be also taken into account in the optimization process.The methods and results can be used as a reference to the MSPA design.

With the increasing of collision accidents among Unmanned Aerial Vehicles (UAVs) the collision avoidance has become a critical problem in free flight airspace of multi-UAV.Firstly a multi-UAV cooperative collision avoidance system was designed and then a novel model predictive control method(MPC) was presented.In the method Extended Kalman Filter (EKF) was used to predict trajectories of obstacles and target in uncertain environment the environment information was shared among UAVs by inter-UAV communication and multi-UAV cooperative collision avoidance guidance strategies were made based on MPC.The simulation results demonstrate the validity of the method and the obvious effect of cooperation mechanism.