AVIC Xian Flight Automatic Control Research Institute

Fengcheng, China

AVIC Xian Flight Automatic Control Research Institute

Fengcheng, China

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Han Z.-F.,Nanjing University of Aeronautics and Astronautics | Liu J.-Y.,Nanjing University of Aeronautics and Astronautics | Li R.-B.,Nanjing University of Aeronautics and Astronautics | Gao G.-G.,AVIC Xian Flight Automatic Control Research Institute
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2016

In order to improve the acquisition sensitivity of Beidou receiver and solve the problem that the coherent integration time is limited by the data bit jump and the NH code phase change, a weak-signal acquisition algorithm is put forward based on differential correlation. Firstly, based on the characteristics of Beidou signal, some common weak-signal acquisition algorithms were analyzed. Secondly, a differential correlation algorithm with sampling point delay was designed. By means of an orthogonal sampling method, the complex intermediate frequency data was obtained, and then the FFT transform was used to realize the parallel search of code phase and carrier frequency. Finally, the simulation verification was carried out by using software receiver, which shows that the differential correlation integrations of 5 ms, 10 ms and 20 ms are realized, and the signal-to-noise ratio is increased by about 7 dB, 10 dB and 13 dB, respectively. This algorithm greatly weakens the influences of NH code phase change and Beidou signal bit jumps, and can effectively improve the receiver's acquisition capacity for weak-signals. Compared with traditional algorithm, the parallel search algorithm based on FFT algorithm can significantly reduce the acquisition time, and is applicable to all kind of Beidou and GPS signals without considering the navigation message differences between GEO and non-GEO. © 2016, Editorial Department of Journal of Chinese Inertial Technology. All right reserved.

Suo X.,Beihang University | Yang Y.,Beihang University | Yang M.,Beihang University | Ma H.,AVIC Xian Flight Automatic Control Research Institute | Zhang B.,AVIC Xian Flight Automatic Control Research Institute
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2014

The accurate evaluation of relative intensity noise (RIN) of broad-band sources and its effect mechanism on a fiber optic gyroscope (FOG) are key factors to further improve the performance of FOGs. An intensity noise measurement system is constructed and RINs of four sources with different spectral shapes and degree of polarizations are tested. Then the RINs are calculated with three different effective bandwidths and the accurate RIN model is confirmed by employing the power weighted average (PWA) bandwidth. Based on this research, the random walk coefficient (RWC) model of FOG is modified. A photoelectric detachment high precision FOG is constructed, and the RWC of FOG is tested with four broadband sources and calculated by using the modified model. It is shown that the calculation results are consistent with the experiment results. This indicates that the power weighted average bandwidth and the degree of polarization are key factors determining the RIN of broadband sources and this research is of great value in evaluating the RIN characteristics of different sources and designing high performance FOGs.

Ding X.F.,Beihang University | Li Z.,AVIC Xian Flight Automatic Control Research Institute
Applied Mechanics and Materials | Year: 2014

Interior permanent magnet synchronous motor (IPMSM) systems are vulnerable to uncontrolled generation (UCG) when the inverter switches loss their drive signals suddenly during flied weakening high speed operation. At this point, uncontrolled rectifier is composed by freewheel diodes in the inverter, the current comes from the motor through the rectifier, and then charges the battery. This paper develops a simple analytical model of this system firstly, and then carries out the simulation of UCG transient process to investigate the impact of the motor speed, battery capacity and other factors on UCG and feedback-power obtained throughout the process. Moreover, circuit improvement is presented in order to avoid destruction risk of the battery, motor, inverter and other relevant components during UCG. © (2014) Trans Tech Publications, Switzerland.

Ding X.F.,Beihang University | Chang H.,AVIC Xian Flight Automatic Control Research Institute
Applied Mechanics and Materials | Year: 2014

This paper presents an investigation into the losses and thermal characteristics of induction motors operated from pulse width-modulated (PWM) voltage supply in comparison to that operated from sinusoidal voltage supply. It was concluded that due to the abundant harmonics in the PWM waveforms, significant losses are induced in the motor by the inverter supply. The temperature ascends correspondingly. Experiments were conducted with no load and with load conditions. The losses and thermal characteristics were calculated using finite element analysis (FEA) and validated by the experiments. © (2014) Trans Tech Publications, Switzerland.

Chen Z.-J.,Beihang University | Zhang R.-L.,AVIC Xian Flight Automatic Control Research Institute | Zhang P.,Beihang University | Zhou R.,Beihang University
Zidonghua Xuebao/Acta Automatica Sinica | Year: 2013

The development of flight control is facing unprecedented opportunities and challenges. According to the new demands and new technological features of future flight vehicles, the opportunities and challenges of flight control are analyzed from the following five aspects: 1) new characteristics of flight vehicles; 2) information-oriented environment; 3) autonomous of unmanned systems; 4) high-reliable reconfigurable fault-tolerant systems; 5) assessment and validation of flight control systems. To exploit the opportunities and meet the challenges, the following five research aspects should be strengthened: 1) new concepts, theories and methods with respect to new characteristics of flight vehicles; 2) information-oriented integration of control, computing and communication, and integration of control, decision-making and management; 3) high level autonomous unmanned systems; 4) high-reliable and reconfigurable fault-tolerant flight control system; 5) high-efficient, high-reliable assessment and validation on flight control systems.

Ma Y.,Northwestern Polytechnical University | Ma Y.,AVIC Xian Flight Automatic Control Research Institute | Zhang Z.,AVIC Xian Flight Automatic Control Research Institute | Han Z.,AVIC Xian Flight Automatic Control Research Institute
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2014

By means of the diffraction loss sensitivity of the diaphragm, the anti-alignment capability of ring laser gyro (RLG) is analyzed numerically. Deriving from the condition of mode suppression of RLG, the lower limit of mode suppression ratio (MSR), which is defined as the ratio of the loss of a higher order transverse mode to that of the primary transverse mode, is calculated to obtain the optimal diaphragm diffraction loss sensitivity. The dependence of the lower limit of MSR (LLMSR) for a RLG on its gain level as well as its total mirror loss is investigated both numerically and experimentally, with the results showing that the higher the gain level, the higher the LLMSR, while the higher the total mirror loss, the lower the LLMSR. These results will be of great significance for the MSR optimizing control during the resonator alignment of RLG.

Wen Z.,AVIC xiAn Flight Automatic Control Research Institute | Zhu X.,AVIC xiAn Flight Automatic Control Research Institute
2014 IEEE Chinese Guidance, Navigation and Control Conference, CGNCC 2014 | Year: 2015

There is an inherent coupling between roll rate and sideslip during powered approach phase. The notion of sideslip is opposite to the sign of roll rate in low angle of attack scenarios. The proverse will degenerate the handling quality and decentralize the energy of pilot for line up during powered approach. In the current work, the mixed H∞/H2 LPV approach is presented to solve aircraft lateral-directional axis decoupling control during powered approach. H2 can guarantee the performance of the closed-loop system with respect to the disturbance and reduce the coupling between different channels, and make the aircraft handling quality achieve the desired handling quality and reduce the workload of the pilots. The aircraft model is linearized at different operating points to obtain an LPV open model, whose state-space entries depend on angle of attack which is a time-varying parameter and is able to be measured in real time. Besides, the closed-loop system performance can be further improved by employing the switching control theory of piecewise multi-Lyapunov functions. © 2014 IEEE.

Lei B.-Q.,AVIC Xian Flight Automatic Control Research Institute | Zeng J.,AVIC Xian Flight Automatic Control Research Institute
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2014

An improved efficient method based on parameter sequential reuse is presented in order to reduce the computation burden of Multiple Solution Separation(MSS) method in inertial aided satellite integrity monitoring. Based on MSS method and its computational complexity analysis, a low-order processing MSS method is deduced with sequential processing. With the help of system structure and correlations of filters measurements, a filter parameter reuse method is proposed to avoid parameters replication computation. Simulation experiments are implemented by changing the fault involvement moment and visible satellite numbers, and the computational complexity between proposed method and MSS method are compared. The simulation results show that the new improved method can effectively reduce the computation burden of MSS and is convenient in practical application.

Jiang X.,Dalian University of Technology | Jiang X.,Shenyang Aerospace University | Duan F.,Dalian University of Technology | Tian H.,Dalian University of Technology | Wei X.,AVIC xiAn Flight Automatic Control Research Institute
Reliability Engineering and System Safety | Year: 2015

The goal of this study is to propose a reliability centered predictive maintenance scheme for a complex structure Inertial Navigation System (INS) with several redundant components. GO Methodology is applied to build the INS reliability analysis model - GO chart. Components Remaining Useful Life (RUL) and system reliability are updated dynamically based on the combination of components lifetime distribution function, stress samples, and the system GO chart. Considering the redundant design in INS, maintenance time is based not only on components RUL, but also (and mainly) on the timing of when system reliability fails to meet the set threshold. The definition of components maintenance priority balances three factors: components importance to system, risk degree, and detection difficulty. Maintenance Priority Number (MPN) is introduced, which may provide quantitative maintenance priority results for all components. A maintenance unit time cost model is built based on components MPN, components RUL predictive model and maintenance intervals for the optimization of maintenance scope. The proposed scheme can be applied to serve as the reference for INS maintenance. Finally, three numerical examples prove the proposed predictive maintenance scheme is feasible and effective. © 2015 Elsevier Ltd. All rights reserved.

Guo S.,Northwestern Polytechnical University | Song Y.,AVIC xiAn Flight Automatic Control Research Institute | Gao Y.,Northwestern Polytechnical University | Han Q.,Northwestern Polytechnical University
China Communications | Year: 2014

Performance of the Adaptive Coding and Modulation (ACM) strongly depends on the retrieved Channel State Information (CSI), which can be obtained using the channel estimation techniques relying on pilot symbol transmission. Earlier analysis of methods of pilot-aided channel estimation for ACM systems were relatively little. In this paper, we investigate the performance of CSI prediction using the Minimum Mean Square Error (MMSE) channel estimator for an ACM system. To solve the two problems of MMSE: high computational operations and oversimplified assumption, we then propose the Low-Complexity schemes (LC-MMSE and Recursion LC-MMSE (R-LC-MMSE)). Computational complexity and Mean Square Error (MSE) are presented to evaluate the efficiency of the proposed algorithm. Both analysis and numerical results show that LC-MMSE performs close to the well-known MMSE estimator with much lower complexity and R-LC-MMSE improves the application of MMSE estimation to specific circumstances. © 2013 IEEE.

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