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An J.-X.,Tsinghua University | Wang G.-Q.,China National Aeronautical Radio Electronics Research Institute | Li S.-F.,Tsinghua University | Zhu J.-H.,Tsinghua University
Ruan Jian Xue Bao/Journal of Software | Year: 2010

As the size and complexity of mission-critical application software continues to grow, the cost of Software Testing (ST) is also increasing. The numerous methods and processes used to evaluate ST dynamically and quantitatively to improve testing efficiency serve as practice problems in the ST field. Based on multi-dimensional test coverage models, this paper proposes a dynamic evaluation method for ST and discusses it from the viewpoint of testing monitoring information, dynamic analysis and evaluation models, and testing optimized strategy. Furthermore, a concept, Synthetic Test Coverage (STC), is defined in this paper, and its empirical formulas are also presented. Examples show that the methods are useful in helping ST evaluation groups to track and control the effects of ST and for improving the user's ability to observe and control the ST process. © by Institute of Software, the Chinese Academy of Sciences. All rights reserved.

Liu K.,Shanghai Maritime University | Guo L.,Northwestern Polytechnical University | Chen J.-S.,China National Aeronautical Radio Electronics Research Institute
Guangzi Xuebao/Acta Photonica Sinica | Year: 2010

A novel image fusion method based on Contourlet domain hidden Markov tree models is proposed. Contourlet transform provides a flexible multiresolution, local and directional image expansion, and also a sparse representation for two-dimensional piecewise smooth signals building images. Contourlet HMT can capture all inter-scale, inter-direction, and inter-location dependencies of the Contourlet coefficients. Aiming at the different frequency bands of Contourlet decomposition with different characteristics, different fusion rules are applied to different subbands. In the low-frequency information, the weighted average mean is used to obtain the fused low-frequency information. Contourlet HMT is applied to design low-frequency information rule, the fusion method has the ability to strengthen the relationship among the Contourlet coefficients, extract more detailed and exact information from the original images. The fused images by the proposed algorithm exhibit good performance both in subjective and objective standards. Experimental results also show the simplicity and effectiveness of the method and its advantages over the conventional approaches.

Gu Q.,China National Aeronautical Radio Electronics Research Institute | Wang G.,China National Aeronautical Radio Electronics Research Institute | He Y.,China National Aeronautical Radio Electronics Research Institute
15th AIAA Aviation Technology, Integration, and Operations Conference | Year: 2015

While Distributed Integrated Modular Avionics (DIMA) architecture provide more flexibility to the used hardware, which does not necessarily have to be in a single box. It may be split-up into several smaller hardware units, distributed all over the aircraft connected by a safety-critical communication system. An important characteristic of the distributed approach is enhanced fault-tolerance through reconfiguration - shared spare computing resources are provided in the system which are dynamically allocated to failing applications when necessary. The paper explored the reconfiguration issue for IMA architectures in the DIMA. The solution proposed for introducing reconfiguration capabilities in the DIMA architectures is developed and an reconfiguration approach is presented. To demonstrate the feasibility of reconfiguration implement mechanism, A DIMA workflow based scheduler is developed for configuration switching with scheduling policy based on runtime failure. Furtherfore, an fault recovery via reconfiguration is illustrated. Experiment result shows that the approach can optimize the computational power or other hardware utilization during the various mission phases or to guarantee the availability of essential functions after hardware failures. © 2015 American Institute of Aeronautics and Astronautics Inc, AIAA. All right reserved.

Yu T.,China National Aeronautical Radio Electronics Research Institute
2010 6th International Conference on Wireless Communications, Networking and Mobile Computing, WiCOM 2010 | Year: 2010

The method by single station speed measurement presented in reference [1] is further expanded. This calculation method can directly survey the uniform flight speed of target, only based on the actual measured frequency, by three stations linear array with very short baseline. Firstly, making use of Doppler changing rate, we can obtain both the specific value of advance angle and the specific value of frequency difference between adjacent measuring stations. Then, by combining it with the specific value of Doppler shift between adjacent measuring stations, the initial solution of advance angle can be solved. In order to exactly solve the advance angle, the relationship between tangential velocity and Doppler shift is found by decomposing Doppler shift in each detection nodes which is used for iterative computation. And then, the tangential velocity of Doppler changing rate is replaced by the one obtained from Doppler shift and iterative computing equation is constructed. The elementary analog calculation shows that analog error is not inversely proportional to basal line length and the iterative program can still produce true result when the basal line length is by far less than a wavelength. © 2010 IEEE.

Yu T.,China National Aeronautical Radio Electronics Research Institute
Tongxin Xuebao/Journal on Communications | Year: 2010

On the assumption that spacecraft was uniform motion alone straight line, a measurement method that could rapidly survey spacecraft orbital velocity only by use of single ground station was presented compositely making use of the ratio relationship of Doppler changing rate and velocity identity between adjacent measuring node. The reliability of derived formula was verified by analog simulation. The error analysis shows that formula measurement accuracy is inversely proportional to the wavelength based on frequency measurement technique. This method can be also applied to single-observer passive location.

Yu T.,China National Aeronautical Radio Electronics Research Institute
Proceedings - 2010 International Conference on Communications and Intelligence Information Security, ICCIIS 2010 | Year: 2010

An analytic method solving Doppler changing rate is presented only by measuring Doppler shift or measured value of frequency. On condition that aerial vehicle is uniform motion, a Doppler direct ranging formula can be firstly derived by making use of the velocity vector identity, the relation between Doppler changing rate and tangential velocity as well as the specific value of Doppler changing rate at neighbor node. As soon as this ranging formula is substituted into the expression of Doppler changing rate, the analytic formula solving Doppler changing rate can be obtained. The analog calculation shows that the relative error derived formula is less than 0.01%. © 2010 IEEE.

Yu T.,China National Aeronautical Radio Electronics Research Institute
Frontiers of Electrical and Electronic Engineering in China | Year: 2010

A new direction finding (DF) method, in which the high-accuracy measuring can be realized only with single baseline, is presented used for airborne based on Doppler-phase measurement. The analysis discovers that the integer of wavelength in radial distance can be directly derived compositely, making use of the velocity vector equation and Doppler shift, as well as Doppler changing rate equation. From this, the integer difference of wavelength in path length difference of radial distance between two adjacent antenna elements can be obtained. As soon as the value less than a wavelength in path length difference is determined by phase difference measurement, the direction angle of target can be obtained. As compared with now existing interferometry first determining phase difference, this sort of direction finding method combining Doppler with phase difference first by determining path length difference does not have phase ambiguity nor require restricting base length. By simple mathematical identity transformation, we can prove that the equation derived in this paper is equivalent to an existing one from phase interferometry. The new method presented in this paper will certainly increase new developing force for the research and development of airborne single station direction finding system. © 2010 Higher Education Press and Springer-Verlag Berlin Heidelberg.

Wang G.,China National Aeronautical Radio Electronics Research Institute
AIAA/IEEE Digital Avionics Systems Conference - Proceedings | Year: 2012

Integration technology of avionics system is a core technology of avionics for all new generation aircrafts. In accordance with the development of integration technology for avionics, this paper describes the composition and structure of avionics system integration technology, analyzes the mechanism and methods of the technology, discusses the abilities and objects of integration technology for avionics system. It also deeply discusses the idea, framework, content, constitution of structural integration, information fusion and mission synthesis of integration for avionics system. © 2012 IEEE.

Li J.,China National Aeronautical Radio Electronics Research Institute | Ding Y.,China National Aeronautical Radio Electronics Research Institute | Fang Z.,China National Aeronautical Radio Electronics Research Institute
Procedia Engineering | Year: 2015

Considering the environments and requirements of the UAV data link, this paper presents an adaptive information transmission method. When transmitting the remote control command data, spectrum spread system is used to improve reliabilityof the data link. When transmitting the high rate information such as videos and images, a three-processing-channel optimum strategyis used to improve the reliability in different channelconditions.Channel 1 is based on Gardner timing recovery and MCMA equalizer, Channel 2 is based on spread spectrum code recovery andMCMA equalizer, Channel 3 is based on Gardner timing recovery and carrier recovery.The strategy computes the confidence level of each process channel and chooses the best one as the output. Besides, the typical channel which the UAV encountered isanalyzed and modeled. Experiments show that this design can achieve good performancein complex environments. © 2015 The Authors.

Wu J.-M.,China National Aeronautical Radio Electronics Research Institute | Wang J.-Y.,China National Aeronautical Radio Electronics Research Institute
AIAA/IEEE Digital Avionics Systems Conference - Proceedings | Year: 2012

Facing the growing complexity of the Integrated Modular Avionics (IMA) system design, an enhanced IMA system design and verification approach based on the rapid prototyping is presented in this paper. General approach to avionics development includes three phases: conceptual development, prototype development and engineering development. In the conceptual development phase, the system requirements are validated by means of system modeling and simulation. The functions of system are validated and tested iteratively by simulation based on models. In prototype development phase, the prototypes based on models and their execution platforms are designed to verify the dynamics of system and performance in real time. With these prototypes and platforms, it is possible for the developer to test and validate processing capabilities of system at early phase of the system development process. In engineering development phase, the system is designed in details according to modified requirements and refined prototype. The focus of the approach proposed in the paper is to validate the system requirements and verify the system design at early phase of the system development process in order to reduce large modification at the later stages in the development due to errors in early design phase. System modeling and prototype simulation are emphasized to find the designing errors due to the misunderstandings in requirement specification. System models are used to verify system design iteratively and reused in different system design. An example is described to demonstrate the effectiveness of the approach. © 2012 IEEE.

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