Abstract:The universal quality characteristics of traditional equipment, such as reliability, maintainability, etc., can be characterized by the quality characteristics in a certain aspect of an equipment from different sides. In order to analyze the equipment quality, some parameters are put forward, such as Reliability, Maintainability, safety, Supportability etc. But, each of these parameters only reflects one attribute of the equipment partially. Hence a compound parameter is necessary to show the comprehensive quality attribute of the equipment during the operational process. In this study, an Equipment Operational Integrity (EOI) is put forward, and defined as the attribute existence when equipment is sound and unimpaired while providing the desired level of equipment safety, performance, durability, supportability, survivability and recoverability. Then, a quantitative measurement method is proposed, which uses Equipment Operational Integrity Degree (EOID) to measure EOI, Io=f(U,A,S,C,Su,Rc), linearly simplified as Io=UASCSuRc. And Io is evaluated based on durability degree U, availability degree A, safety degree S, livability degree C, survivability degree Su and recoverability degree Rc. Also, the Equipment Readiness Rate R can be used to express EOI, R=Eintact/Etotal, here Eintact is intact equipment amount and Etotal is total equipment amount. And the connotation of the EOI is discussed in details, which reveals that the Equipment Operational Integrity tells if the equipment is capable to operate, the Equipment Operational Suitability tells if the equipment is suitable to operate, the Equipment Operational Effectiveness tells if the equipment is effective to operate, and all of them compound the three basic attributes of equipment. Meanwhile, the durability, survivability and recoverability of equipment are explained carefully, including the concepts and measurement methods. And the interference model of equipment CapabilityLoad is presented to show the equipment failure probability due to the weak loadbearing capabilities comparing with the acting loads during equipment operating process.

Abstract:The equivalent system method is one of the important methods for evaluating the flight quality of aircraft. The least square method and the maximum likelihood method are widely applied in the formulation of equivalent systems, but both of them require highly of the initial value and are easy to fall into a local optimal solution leading the fitting accuracy to be low. In view of the abovementioned facts, the core formula of traditional differential evolution algorithm is improved, and a new idea of equivalent system fitting based on average differential evolution algorithm is proposed. In addition, because there is a certain percentage of noise interference in the data, the ideal 3211 signal and the 3211 signal mixed with 10% and 30% white noise are used as system inputs, respectively. The difference between the differential evolution algorithm and the traditional equivalent matching method is studied, and the results show that the average differential evolution algorithm has a strong antinoise interference ability, good robustness, good identification effect, and at the same time the processing ability of noise is strong.

Abstract:In order to solve the misjudgment and timeconsuming problem in manual identification of aeroengine working condition, and to improve the accuracy of the recognition, an intelligent recognition method based on principal component analysis（PCA）and a random forest（RF）is proposed. Firstly, PCA is used to reduce the dimensionality of the original flight data preprocessed, and the processed data on the basis of aeroengine working condition are grouped, and then RF are constructed. Secondly, the recognition effect of several classification methods is made in comparison with each other. At last, the method is used to recognize the working condition of one sort. The experiment results indicate that the recognition accuracy is 97.89% by this method. And this method is able to recognize the aeroengine working condition fast and accurately, and simultaneously is able to apply to the research related to the aeroengine working condition.

Abstract:Based on the analysis of signal transmission mechanism of track circuit combined with its electrification characteristics, this paper proposes a new method of adding track signal acquisition points to realize fault location of track circuit compensation capacitor and estimate its residual life. Firstly, a hidden semi-Markov model of each compensation capacitor acquisition point is constructed by combining historical data with simulation test data, and the realtime operation status of compensation capacitor is monitored by the trained hidden semi-Markov model. Secondly, through the analysis of track circuit compensating capacitor operation data offset state, the normalized shunt current of each monitoring point is analyzed by safety offset distance, the leakage location of compensation capacitor beyond the safe offset state is carried out, and the residual life of compensation capacitor is estimated by combining the monitoring data with the hidden semi-Markov model after training. Finally, combined with the simulation test data, the rail acquisition point of compensating capacitor can be used to locate the leakage of compensating capacitor and estimate its residual life, and the accuracy of residual life estimation is more than 90%, optimizing the maintenance mechanism of compensating capacitor.

Abstract:In view of the open circuit fault diagnosis of threephase inverter, a fault diagnosis method based on residual theory with dynamic reference quantity is proposed. This paper is to utilize the existing phase voltage sampling signal of the inverter closedloop control system, take the phase voltage waveform with one period delay as a dynamic reference, and obtain the voltage residual waveform by comparing the dynamic reference voltage signal with the current phase voltage signal through setting a reasonable fault detection threshold for realizing the accuracy diagnosis of the open circuit fault of the inverter. The simulation results show that this method has the ability to resist unbalanced load and the load mutation interference, and the diagnosis time is less than one cycle, and has the advantages of low complexity and easy implementation.

Abstract:Aimed at the problem that the traditional multiple reference consistency check (MRCC) algorithm based on maximum likelihood estimation criterion is failure to effectively distinguish the fault sources of reference station receivers in ground based augmentation system(GBAS), the MRCC algorithm of GBAS ground facility is studied. The theory of GBAS B Value is analyzed, and by a processing flow of MRCC algorithm effectively detected the failed receiver is given, and then a calculation method of B Value threshold based on Gaussian overbounding is proposed. The validation experiments are carried out by using the GBAS prototype. The results show that when there are no faults in the ground facility receivers, the calculated Bvalue of each reference station is within the detection threshold and the consistency check is passed. Once a receiver fails, the trouble can be effectively identified, and when the failed receiver is removed, the B value of the remaining reference stations can be restored to the normal range, and the effectiveness of the proposed algorithm is verified.

Abstract:Aimed at the problem that the satellite signals in integrated navigation have an effect on error, a new robust Kalman filter algorithm based on chi-square on test and Newton interpolation is proposed. The algorithm is to improve the positioning accuracy of chi-square test to the fault measurement value by taking the residual error of the measurement value disobeyed the Gaussian distribution with the mean value being zero as a theoretical basis and the simulation experiment as a basis through designing a method to select the threshold of chi-square test to meet the significance level requirement. On the basis mentioned above, the Newtonian interpolation polynomial is constructed by using the observed values at the past time and donated to get the new measured values at the current time, and measurement noise is improved by introducing improvement factor, making measurement noise more close to normal value, and finally improving navigation accuracy. The experimental results show that the algorithm proposed in this paper reduces the position error by about 75％ and the speed error by about 80%, compared with the general filtering algorithm, and can also effectively suppress the influence of observed faults and improve the reliability of integrated navigation system.

Abstract:In order to further enhance the detection performance of radar for moving targets on the ground and to achieve spectral coexistence between radar and communication systems, the waveform design is studied for spectral coexistence of airborne Multiple-Input Multiple-Output (MIMO) radar under condition of the environment of ground clutter. Firstly, the peak-to-average-power ratio (PAR) constraint is exerted on the waveform,and then both the global spectrum design and the local spectrum design are considered. Finally, a novel cyclic iterative algorithm is proposed. In process of each iteration, the original nonconvex optimization problem is transformed into a solvable convex optimization problem through the convex approximation, and then the optimal solution of the waveform is obtained directly by using the Feasible Point Pursuit Successive Convex Approximation（FPP-SCA）algorithm. The simulation results show that compared with the existing algorithm, the algorithm not only has still faster operation speed, but also can play a role of PAR constraint in waveform.

Abstract:Aimed at the problems that the radar waveform multicriteria optimization target function is difficult to establish, and in order to reduce the uncertainty of target response and to improve the radar detection performance, a radar waveform design method based on deep neural network is proposed. First, deep neural networks (DNNs) are designed according to the radar echo data. Then, the signals generated based on the SignaltoNoise Ratio (SNR) and the Mutual Information (MI) criteria are randomly mixed, and the corresponding environmental information is used to form a training set, and the DNNs are trained. Finally, taking another part of the signals generated based on the mutual information criterion and its corresponding environmental information as test sets, this paper utilizes the DNNs for generating signals and testing. The experimental results show that if the signals generated by the method taken as a radar emission waveform compares to the signals generated based on the MI criterion alone taken as a radar transmission waveform, the mutual information of the radar echo and the target is increased by 21.37 nat, and the signals of the radar receiving signals are improved. The noise ratio is increased by a maximum of 1.35 dB. Compared with the chirp signals, the corresponding mutual information is increased by 950.76 nat, and the corresponding signaltonoise ratio is increased by 18.23 dB.

Abstract:Firstly, the difficulties and problems of applying time inversion technique to nearfield power synthesis of moving array are analyzed theoretically, and the feasibility of applying time inversion technique to farfield power synthesis of moving array is also discussed. A mathematical model of farfield power synthesis of moving array based on time inversion technique is established. On the basis of this model, by simulating the beam pointing of the retrospective signal when the beacon signal is incident from different directions, the TR signal radiated by the array can achieve adaptive retrospective and is more concentrated beam energy than that of the synthesized beam formed by the traditional phased array method. The 3dB width of the main lobe beam of the synthesized signal when the unit antenna is set as omnidirectional antenna and directional antenna is obtained by simulation. The possibility that the target point is separated from the coverage of the main lobe beam of the synthesized beam due to the relative tangential motion between the array and the target point is eliminated. The influence of random phase error and beam pointing error on the synthesized beam pointing of backtracking signal is analyzed. The simulation results show that the random phase error has little effect on the synthesized beam pointing of backtracking signal, but has a certain of effect on the synthesized signal. The beam pointing error caused by Doppler shift of signal has little effect on the adaptive backtracking of signal. The conclusions can provide a theoretical basis for the practical application of time inversion technology in far-field power synthesis.

Abstract:In view of the flow features, a threedimensional wind field model of airflow over mountain in consideration of the ground friction and the leeward vortex are established based on the theory of potential flow. Taking a certain empennage rocket of 122 mm as an example combined with 6DOF ballistic model, this kind of empennagerocket is studied on its ballistic performance of prior trajectory influenced by the airflow over mountain wind shear. The results show that the airflow over mountain wind shear has a certain impact on the flight time, the range, the side-slip, the falling velocity and the angular motion of a rocket, particularly on the lateral movements of a rocket. The wind field strength is positively related to the influences on a rocket by the airflow over mountain; The changing regularity of ballistic performance when the rocket launched on the windward slope is opposite to that of leeward slope and the ballistic performance is more affected when a rocket is launched on the leeward slope. Within the range of middlelow elevation, the incremental elevation of a rocket is enabled to influence on the range of a rocket by the airflow over mountain, meanwhile the influence on the sideslip may increase correspondingly.

Abstract:Aimed at the problem that the traditional twostage Kalman filtering can only deal with single or part of complex noises, a twostage Kalman filtering fusion algorithm based on sequential decorrelation of noise is proposed in full consideration of the modeling of colored noise and four kinds of noise correlation in multiradar tracking system. First, this paper is to give the order of noise decorrelation which can effectively avoid the coupling of noise correlation, and then to obtain a target tracking fusion model uncorrelated among the colored noise, the process noise and the measurement noise by using the equivalent transformation technology. Finally, the centralized Kalman filtering fusion of multiradar measurement noise correlation system is realized by using the square root decomposition and the unit lower triangular matrix inversion technology.

Abstract:The near space hypersonic gliding target (HGT) is characteristics of highspeed, highmobility motion. In order to improve its tracking accuracy, an improvement on the existing Jerk tracking model is made. In this paper, the idea of firstorder AR model is applied to the real-time estimation of model parameters. The relevant parameters are introduced in the target state equation and measurement equation. And then the parameter adaptive Kalman filter algorithm is constructed based on the improved Jerk model to make the target state, and the model parameters adaptively adjusted at the same time. Finally, based on the HGT simulation trajectory, the proposed model is compared with the traditional Jerk model, and the effectiveness and advantages of improving the Jerk model for HGT tracking are proved.

Abstract:In regard to the typical search route of the antiradiation UAV in the execution of SEAD mission, there are two kinds ofrunwayshaped and “8”shaped. In this paper, the "field coverage rate" index is established to measure the suppression effect of two typical search routes on the target radar, and the optimization of these two typical search routes is realized. For this reason, firstly, the field coverage of the two search routes is obtained by establishing a mathematical model, and then the influence of the turning radius of the UAV and the linear length of the route planning space on the coverage of the two search routes is analyzed. The influence of the horizontal mechanical field of view of the UAV seeker on the theoretical calculation of the field coverage of the two search routes is considered. The calculation results show that the field coverage of the two typical search routes is less than 50% when the planning space size of the route and the turning radius of the drone are fixed, but the field of view coverage of the “8” shaped search route is significantly higher than that of the runwayshaped search route. The “8” shaped search route has a good suppression effect on the target radar.

Abstract:Multi-UAV(unmanned aerial vehicle) cooperative work mode will have important application prospects in future communication. In consideration of the shortage of spectrum resources, this paper establishes a cognitive drone network model, studies the spectrum sensing performance of multiUAV cooperative work, and proposes an optimal fusion criterion to optimize the detection performance. A fast and efficient cooperative spectrum sensing algorithm is proposed to compare the performance of two algorithms under condition of Rayleigh fading and Nakagami fading channels. The simulation results show that: 1) The total error rate of cooperative spectrum sensing can be minimized by using the optimal fusion criterion. 2) The fast cooperative spectrum sensing algorithm can utilize the fewer UAVs for ensuring the detection accuracy of cooperative spectrum sensing, avoiding unnecessary sensing process, reducing the number of secondary users participating in cooperative spectrum sensing, reducing cooperative sensing time, and saving the cost of sensing process. Moreover, compared with the Rayleigh fading channel, this algorithm has better performance under condition of the Nakagami fading channel.

Abstract:Aimed at the problems that both the time-consuming and laborious measures are in existence for making a measurement on the quality of the existing military airport flight area, and there is no reasonable measurement method for the rationality of the airport facilities layout, an idea of satisfaction survey is introduced, and the improved item response theory（IRT）graded response model is adopted for airport flight. The questionnaire design of the facility satisfaction degree is used to fill the blank of the facility use satisfaction questionnaires. A certain military airport is selected as a case and 96 sample databases are used as the basis to conduct unidimensional test and grade response model fitting test. A flight area facility satisfaction design model based on IRT is constructed to delete the items that did not meet the requirements and endow with a new significance to the project parameters. At the same time, the target of the survey is achieved, and a solid foundation is laid for the next extensive survey and the improvement of the survey question bank. The results show that the proposed method is scientific and feasible.

Abstract:In order to solve the drilling problem of mechanical repair to the composite materials, the ultrasonicassisted drilling is researched. First, the mechanism of ultrasonicassisted drilling is studied to both the drill and the cutting edge. Second, the portable ultrasonicassisted drilling system is introduced including the hand drill and the ultrasonic power supply. Third, a design of ultrasonic transducer is analyzed with principle and simulation. The experiments show that by adopting this ultrasonicassisted drilling technique, the drilling flaws, such as laminate, burr, wire drawing, etc., can be decreased compared to the direct drilling without ultrasonic, and simultaneously this method can meet the needs of aircraft battle damage repair (ABDR).