Micro displacement is precisely produced either directly by squirm movement, or indirectly by the enlargement effect from the lever with microstructure, driving by the external force, electric field or magnetic field on the micro displacement devices. For example, the piezoelectric transducer is driven by the voltage, to squirm with micro displacement, based on the converse piezoelectric effect. In this article, we summarize measurement and calibration methods of micro displacement of the PZT used as phase shifter of the interferometer to guarantee a phase-shifting step of λ/8(λ=632. 8nm), based on the researches of our group in recent years. The precise positioning with resolution better than 10 nm is achieved by displacement sensing utilizing the feedback of a capacitor on the PZT.

Considering the problems of the accuracy decline and the divergence of integrated filtering during outages of satellite signal in GNSS/INS integrated navigation, we proposed a new integrated navigation algorithm. With only two visible satellites, the algorithm can obtain stable and reliable positioning result by utilizing the position information and discontinuous pseudo ranges of the two satellites, and the relative movement information at different moments. The positioning result is independent of the existing inertial navigation errors. The correctness and effectiveness of this algorithm are verified through simulations.

The distribution characteristic of the target spatial state changing with the time is defined as the time spectrum of the target. By using the time spectrum information of the target, including its trajectory, speed, maneuverability, and the space coordinate information, the accuracy of ship to air target threat assessment can be improved. In this paper, the objective approach is used together with the subjective one to judge the state of the aerial targets and achieve the purpose of threat sequencing. Examples show that, the proposed method for warship air defense threat assessment can make reasonable use of reconnaissance information, and provide an effective assistant means to the naval commanders for making decision timely.

Aimed at the statistical property estimation of measurement noise in the adaptive Kalman filtering, a method based on α-β-γ filter and second order mutual difference estimation is proposed to estimate measurement noise variance.By constructing a virtual redundant measurement sequence with α-β-γ filter, the second order mutual difference method only adaptive to redundant measurement is extended to single measurement.Based on which, the calculation precision is improved through selection of data and optimization of α-β-γ filter.Experimental result indicates that: compared with traditional adaptive Kalman filter, this method can compute the measurement noise variance more accurately, and restrain the filtering divergence.

In multiple Unmanned Aerial Vehicles (UAVs) cooperation for target area coverage searching, the traditional searching strategy can not make effective detection to moving targets. To solve the problem, a multi-UAV oblique line cooperative searching strategy is proposed, aimed at reducing dead zone and improving the effective coverage area of UAV formation. The UAV sensor model is given, analysis is made to the principle of moving target searching, and the scanning probability model is built up. Simulation results show that the improved searching strategy can accomplish the searching task more effectively. Comparison proves the advantages of the proposed method.

Consensus problem for multi-agent systems has become a hot topic in the control community, and many research achievements have been reported. Most of the literatures mainly consider the case of linear algorithms and measurable agent states, but it is difficult to measure states of the agents directly in some real applications. Consensus problem for second-order, multi-agent systems with nonlinear output network is studied in the paper. To the multi-agent system difficult to measure directly, a consensus protocol design method is proposed respectively for second-order, multi-agent systems with a leader and without a leader. Consensus convergence is proved by using invariant set theorem, and the decision value is derived for the case of multi-agent system without a leader. Finally, the numerical simulations and analysis on different conditions are given to verify the effectiveness of theoretical results.

An optimal Linear Quadratic Gaussian (LQG) control method under event-triggered sampling mechanism is proposed for the linear, discrete stochastic process with white Gaussian noise in networked stochastic system. Considering the joint design of optimum control law and optimum event-trigger law, it is proved that an optimal LQG control law based on event-triggered sampling mechanism can also satisfy the separation theorem. Then, performance cost function is derived, and based on which the optimum event-trigger law and the minimum value of the cost function are obtained by deterministic dynamic programming. Simulation results show that, compared with the optimal time-triggered LQG control under the same conditions, the proposed optimal event-triggered LQG control can save communication resources, decrease the transmission times, and improve the whole control performance at the same time.

As the basis of deterministic delivery of Time-Triggered Ethernet(TTE), the accurate clock synchronization is influenced by synchronization mechanism, clock drift and receive window. A model of node and switch supporting synchronization service was designed to transmit multi-class messages. The time determinability of TTE was studied by theoretical analysis and computer simulation, which verified that TTE could be a deterministic network. Through the study of the effect of clock synchronization accuracy on time triggered communication, the synchronization cycle boundary and receive window boundary of TT message loss event were find, which forms a basis for TTE synchronization parameter settings.

A new path planning method is proposed for the electronic warfare UAVs to find the optimum interference path. The model of a UAV's interference to radar early warning is established. Then, according to the angular velocities of the UAV and the aircraft for penetration relative to the early warning radar and other constraints, the optimum path for a single UAV is obtained. The simulation results show that: the method makes full use of the UAV's speed for covering the aircraft penetration, and can save UAV resources greatly.

To the optimization problem of control parameters for the lateral channel of small UAV(SUAV), H2/H∞ robust optimization design is studied with bandwidth as the control quality index and singular value as the robustness index, and analysis is made to the law of parameter optimization of H2/H∞ robust control. An optimization control objective function is constructed by using Gram stability method, and the weighting coefficients of the objective function are optimized. The feasible region of the objective function is restricted by penalty function to obtain the unique solution for system control parameters. Simulations verify the feasibility and validity of the proposed method, and there can be a trade-off between flying control quality and robustness. The controller designed for lateral channel of small UAV utilizing this method has very good control quality and high anti-disturbance performance, which reaches the expected goal.

In attitude control of quad-rotor aircraft, the conventional Proportion-Integration-Differentiation (PID)closed-loop algorithm has the problems of complex parameter tuning, and large overshoot due to closed-loop zero. According to the system dynamic performance requirements, and by improving the traditional PID control algorithm, an optimal PID algorithm with pre-filtering performance is designed based on the time and the Integral Absolute Error (ITAE) indicators. Matlab-Simulink is used for making contrast experiment to the traditional PID control and optimal PID control with pre-filtering algorithm. The results showed that: 1) The optimal PID control with pre-filter has an adjusting time less than 0. 5 s, and overshoot less than 5%, which can effectively suppressing the impact of closed-loop zero on the overshoot while guaranteeing rapid system response; and 2) The proposed method has higher control quality, and is better than traditional PID control.

This paper briefly introduces the characteristics and test status of active decoy system, as well as decoying efficiency test requirements. The main problems of test pattern of active decoy hardware-in-the-loop simulation are discussed based on existing simulation resource extension. On the basis of the design idea of the overall process closed-loop countermeasure and situation simulation using real active decoy system and anti-radiation missiles, the active decoy hardware-in-the-loop simulation test pattern is established.

In order to improve the capability of low-light-level imaging system for image processing of moving object, a self-adaptive image enhancement algorithm was proposed. This method is based on the combination of multi-frame image processing and target speed estimation, which can decrease the image flicker noise effectively, improve the image contrast, and is applicable for moving target image processing. Test was made to the method on a platform with a Field Programming Gate Array(FPGA) as the core device. The result shows that: With the help of this processing method, the Signal to Noise Ratio (SNR) of images improves a lot from 2. 1 dB to 11. 5 dB when target is still; and the SNR will not decrease as dramatically as general methods do when the target is moving

To solve the problem of long time north-finding of gyroscopic theodolite, a new composite, rapid and accurate amplitude limiting scheme was designed. Taking a certain type of gyroscope theodolite as the prototype, we added a liquid cup on lock-release cup, and installed a damper under pendulous to limit the amplitude roughly. Through monitoring the amplitude of swing, the stepped limiting method was used to accomplish accurate amplitude limiting when it reaches 20′. This method can shorten the north-finding time of the gyroscope theodolite and guarantee the precision, which can accomplish the amplitude limiting in 120 s with an accuracy of 1′.

Aiming at the problem that the tracking data of visual head posture tracker involve time-varying noise, a method for cockpit head posture tracking based on data fusion is designed. According to the corresponding relationship between the space points and image points, orthogonal iteration algorithm is used at first to solve PNP problem. Then, the problem of the time-varying noise is solved by using Sage-Husa adaptive filter instead of EKF. Finally, a linear weighted fusion algorithm is used to fuse head posture data of the Outside-in tracker and Inside-out tracker to obtain head posture with more stable accuracy. Empirical data are used in a series of simulation, the results show that the tracking accuracy of the system is greatly improved and the system is stable and reliable.

A new type of circularly polarized antenna based on Substrate Integrated Waveguide (SIW) is introduced. HFSS simulation software is used for the optimization of the antenn The maximum gain is 7. 3 dB, and the Axial Ratio (AR) is 1. 03 dB when central frequency is 12 GHz. The simulation result shows that the new antenna has high gain and low AR, and also has the advantages of cheap and easy to fabricate.

In angle measurement, the rotation of measured vector may cause cable winding. To solve the problem, a wireless angle measurement system is put forward based on CC1101 Radio Frequency(RF) chip. The tilt sensor is used to collect the angle data in real time, and data transmission is realized by wireless module. Finally, analysis and processing are made to the data received, and the real-time moving state of turntable or platform is obtained. The composition and working principle of the system are presented, a wireless inclination measurement prototype is established based on CC1101 RF chip. The wireless communication module drive program and measurement system application program are given, and angle measurement test is made. Experimental results verify the feasibility of the measurement system.

An adaptive backstepping controller is exploited for a hypersonic vehicle in the presence of uncertain parameters and flexible dynamics. The control laws of velocity subsystem and altitude subsystem are proposed respectively based on dynamic inversion and backstepping design procedure. Low-pass first order filters are introduced to obtain the time derivatives of virtual control laws in altitude subsystem, thus to avoid the explosion of differentiation terms in traditional backstepping design. The uncertain parameters are updated adaptively by using a projection operator, and the possible parameter drift problem is eliminated. Simulation results show that the developed controller is robust to the model uncertain parameters and the flexible effects, and moreover, it can provide fine tracking performance of the velocity and altitude reference trajectories.

The video is composed of many shots, which may have different brightness and main gray level. To effectively increase energy saving rate of different video, a backlight dimming algorithm based on shot characteristics is proposed. The shot segmentation is implemented by using brightness and main gray level. Then classification is performed for each shot based on its brightness and contrast. Different dimming parameters of backlight control are applied for different type of shots. The simulation results for different kinds of video show that the average detection rate is 67. 21% and the average precision is 81. 81%. An engineering prototype was developed to test different kinds of video．The result shows that the overall average energy saving rate is 24. 89%．

Digital remote sensing images have the features of real-time processing and huge amount of data. To meet the needs of high-capacity and high bandwidth in image processing system, DDR3 controller in spartan6 FPGA is used to realize reading/writing operation to DDR3 memory, which converts the complicated timing operation into a simple user interface. The features of DDR3 memory and the principle of DDR3 controller are introduced, and the hardware test to the DDR3 controller shows that it can work steadily. The controller is used successfully in the real-time image compression system by parameter configuration and interface design. With high-capacity and high bandwidth, DDR3 memory has found a wide application.

The speed and the precision are the two most important criteria for the result of image registration. Scale Invariant Feature Transform (SIFT) is a classical algorithm for feature extraction and description. The SIFT has the characteristics of scale invariance and rotation invariance, while the 128D descriptor has a big adverse effect on the speed of image registration. To improve the time-consuming descriptor, we propose a novel method. The SIFT feature points are extracted at first. Then, ORB algorithm is used to define the main orientation of the points. Based on the moments features of the feature points'neighborhood image block, a 8D descriptor is formed for describing the SIFT feature points of the image and realize SAR image registration. The experimental results demonstrate that the proposed method can improve the registration speed greatly while keeping the image registration precision.

The high complexity of shape, attitude and size of the infrared images of the aerial aircrafts may result in low recognition rate and processing speed to the classical infrared target recognition methods. To solve the problem, we proposed a method for the aircraft target recognition based on infrared images and feature fusion. The proposed method made full use of the algorithms of scale invariant feature transform and singular value decomposition. The recognition features of infrared image were extracted at first, and then the fusion feature vector was constructed. The aircrafts were recognized by BP neural network. Based on infrared image database of five types of aircraft, we made experiments for comparision of our method with the classifical methods. The result show the effectiveness and feasibility of the method.

A large number of false positives and false negatives may emerge when using traditional kernel principal component analysis to make fault diagnosis to dynamic systems. To solve the problem, a step auto-regression Kernel Principal Component Analysis (KPCA) algorithm is proposed. The method establishes a fault diagnosis model based on step dynamic strategy. Based on sliding window mechanism and exponential weighting idea, it updates the diagnosis model by continuously adding weighted, real-time data. T2and SPE statistic are used to detect whether the system has faults or not. The method is applied to fault detection of diesel engine valve, and the results indicate that the algorithm can not only make full use of original data and real-time dynamic information to update the model automatically, but also reduce the calculation cost, detect abnormal working status earlier, and improve the accuracy of fault diagnosis. Furthermore, the method can make diagnosis result more accurate and reliable by increasing the fault sensitivity.