Key Laboratory of Space Object Measurement

Beijing, China

Key Laboratory of Space Object Measurement

Beijing, China
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He S.-Q.,University of Electronic Science and Technology of China | Wang T.,University of Electronic Science and Technology of China | Wang X.,University of Electronic Science and Technology of China | Dang H.-J.,Key Laboratory of Space Object Measurement
Dianzi Keji Daxue Xuebao/Journal of the University of Electronic Science and Technology of China | Year: 2017

In this paper, conventional missile targets are divided into basic scattering cells, such as disks, cylinders, cones and ellipsoids. By carrying on the parameterized compositional modeling, analytical calculation of integrals, and superposition the field contribution of each unit, we can obtain the scattering fields of missile-like objects in time. Consequently, the electromagnetic scattering characteristics such as RCS, the range profile and ISAR images are available. The numerical results demonstrate the proposed method can meet the real-time requirement as well as the high precision. Numerical software is developed and it gives a best support to the RCS calculation and design evaluation of missile targets in engineering application. © 2017, Editorial Board of Journal of the University of Electronic Science and Technology of China. All right reserved.


Zhang Y.,Beijing Institute of Technology | Zhang Y.,Key Laboratory of Space Object Measurement | Shi Q.,Beijing Institute of Technology | Shi Q.,Key Laboratory of Space Object Measurement | And 4 more authors.
Guangxue Xuebao/Acta Optica Sinica | Year: 2017

According to the error characteristics of the echo of diffuse reflection laser ranging, a real-time echo-photon detection method is proposed based on the motion compensation and robust estimation. By using motion compensation, one can increase the number of accumulation photons to provide a reliable initial value. Based on this, by adoption of robust estimation scheme to removing gross errors of observation data, one can realize the real-time online detection of echo-photon effectively. Experiment results show that, under the condition of low signal-to-noise ratio, the method can not only suppress the impact of noises, but also effectively solve the real-time signal detection problem in diffuse reflection laser ranging. © 2017, Chinese Lasers Press. All right reserved.


Zhao H.,Beijing Institute of Technology | Huang J.,Beijing Institute of Technology | Huang J.,Key Laboratory of Space Object Measurement | Liang X.,Beijing Institute of Technology | And 3 more authors.
Lecture Notes in Electrical Engineering | Year: 2018

Environmental matrix S in the guidance instrument systematic error model is usually seriously ill-conditioned, which has a strong impact on the accuracy of the result of error separation. In this paper, new algorithm for guidance instrument error separation is presented. Based on some numerical iterative method, the new algorithm firstly converts the ill-conditioned algebraic equations to the corresponding stiff dynamic system, and stiff stable numerical method is applied to solve the stiff dynamic system. The convergence of the new method is proved. The method which used to solve the stiff dynamic system is given in the paper. Compared with the PB method (primary Bayesian), the numerical experiments illustrate that the new method is more effective for the Guidance Instrument Error separation. © Tsinghua University Press, Beijing and Springer Nature Singapore Pte Ltd. 2018.


Zhao P.,Beijing Institute of Technology | Zhao P.,Key Laboratory of Space Object Measurement | Zhang Y.,Beijing Institute of Technology | Zhang Y.,Key Laboratory of Space Object Measurement | And 4 more authors.
Lecture Notes in Electrical Engineering | Year: 2018

Because of the strong background noise, the weak echo signal in diffuse reflection laser ranging is very difficult to detect in daylight, which limits the extensive application of diffuse reflection laser ranging. In this paper, the multi-hit method is proposed to solve the weak signal detection problem of diffuse reflection laser ranging in daylight. First of all, a fast performance prediction method for multi-hit Geiger-mode avalanche photodiode (GM-APD) is introduced. Then, taking the typical parameters of the diffuse reflection laser ranging system, the detection probability of the echo signal is analysed under different firing times. Furthermore, effective detection ratio is defined to evaluate the extraction cost of the echo signal. The theoretical analysis shows that processing only a few firings in one gate window can result in large increase of detection probability for diffuse reflection laser ranging in daylight. Meanwhile the optimization of the firing time for GM-APD can increase the effective detection ratio and reduce the extraction cost of the echo signal. Finally, the correctness of the theoretical analysis is verified by the system simulation. Therefore, the multi-hit method is one of the feasible ways to detect the weak echo signal of the diffuse reflection laser ranging in daylight. © Tsinghua University Press, Beijing and Springer Nature Singapore Pte Ltd. 2018.


Zhao P.,Beijing Institute of Technology | Zhao P.,Key Laboratory of Space Object Measurement | Zhang Y.,Beijing Institute of Technology | Zhang Y.,Key Laboratory of Space Object Measurement | And 3 more authors.
Science China Technological Sciences | Year: 2015

The performance of detector limits the overall performance of laser ranging system. And the design of multi-hit detector is one of the feasible ways to promote the performance of detector. Currently, the segmentation method or the recursive method is commonly used to analyze the multi-hit detector model. To the best of our knowledge, this paper is the first to propose a combinatorial method to solve the multi-hit detector model from the perspective of discrete time. Then, universal formulas of total signal detection probability and the average count are deduced based on the Poisson distribution signal. Furthermore, analysis is made to figure out how the average count changes with different parameters, such as the dead time, gating time, rate intensity. As a result, for GM-APD, the multi-hit detector model is verified advantageously compared to the single-hit detector model in improving the average count theoretically. Meanwhile, a discrete step feature is presented when average count changes with dead time or the gating time, which is of great significance in gating time optimization. © 2015, Science China Press and Springer-Verlag Berlin Heidelberg.


Peng Z.,Beijing Institute of Technology | Peng Z.,Key Laboratory of Space Object Measurement | Yan Z.,Beijing Institute of Technology | Yan Z.,Key Laboratory of Space Object Measurement | And 2 more authors.
Optics Letters | Year: 2015

This Letter, for the first time, proposes the look-back-upon tree recurrence (LTR) method based on the Poisson statistics for discrete time to predict the performance of Geigermode avalanche photodiodes with a short dead time. The results of the proposed method correspond to the results of previous methods for diverse input fluxes. The LTR method possesses very low time and space complexity to allow for the real-time analysis of the Geiger-mode avalanche photodiodes' performance over the entire ranges of dead time and input diversity. © 2015 Optical Society of America.


Zhao P.,Beijing Institute of Technology | Zhao P.,Key Laboratory of Space Object Measurement | Yuan Y.,Beijing Institute of Technology | Yuan Y.,Key Laboratory of Space Object Measurement | And 3 more authors.
Chinese Optics Letters | Year: 2016

This Letter introduces a trigger-controlled Geiger-mode avalanche photodiode (GM-APD). A hierarchical lookback-upon tree recurrence method is given to predict the performance of trigger-controlled GM-APDs under different trigger-count upper limits. In addition, the normalized detection probability is defined to evaluate the detection performance of trigger-controlled GM-APDs in typical weak optical signal detection (impulse noise and continuous noise situations). Theoretical analyses show that the trigger-controlled GM-APD improves the detection performance of GM-APDs in weak optical signal detection via the optimization of the trigger-count upper limit, compared with single-trigger and multi-trigger GM-APDs. © 2016 Chinese Optics Letters.


Zhao P.,Beijing Institute of Technology | Zhang Y.,Beijing Institute of Technology | Wang K.,Beijing Institute of Technology | Qian W.,Key Laboratory of Space Object Measurement
IEEE Photonics Technology Letters | Year: 2016

This letter proposes a universal discrete-time recurrence (UDR) method to predict the response performance of Geiger-mode avalanche photodiodes (GM-APDs), where performance prediction for a free-running GM-APD is realized beyond the gate-limit assumption for the first time. The dead time effect is summarized as the discrete-time correlation law, and the afterpulsing is first incorporated in the performance prediction theory as an equivalent noise source. Simulations with appropriate parameters verified the high accuracy and low calculation-time requirements of the UDR method. © 1989-2012 IEEE.


Wu B.,Beijing Institute of Technology | Wu B.,Key Laboratory of Space Object Measurement | Yuan Y.,Beijing Institute of Technology | Yuan Y.,Key Laboratory of Space Object Measurement | And 2 more authors.
Dianzi Yu Xinxi Xuebao/Journal of Electronics and Information Technology | Year: 2016

In order to solve the problem of low recognition accuracy of Continuous Phase Modulation (CPM) which is non-linear and with memory, a new maximum likelihood modulation recognition approach using memory factor is proposed in this paper. The approach defines the mapping symbol which has the time-homogeneous Markov property and generates the memory factor by calculating the posterior probability of the mapping symbol. Then, combining with the CPM decomposition and the EM algorithm, the time separable and channel parameter estimable likelihood function is deduced for CPM signals. The proposed approach has characters of low required symbol number, wide range of applicable SNR, large variety of recognizable CPM signals, high recognition accuracy and strong robustness to phase error. Simulation results show that the recognition rate of 8 kinds of CPM signals can reach more than 95% when the symbol number is 200, SNR is 0 dB and the phase error is arbitrary. © 2016, Science Press. All right reserved.


Zhao P.,Beijing Institute of Technology | Zhao P.,Key Laboratory of Space Object Measurement | Zhang Y.,Beijing Institute of Technology | Zhang Y.,Key Laboratory of Space Object Measurement | And 2 more authors.
Guangxue Xuebao/Acta Optica Sinica | Year: 2015

In order to realize the echo online extraction for diffuse reflection laser ranging when echo photons are blocked by a large amount of noise photons, an echo online extraction method based on time correlation is proposed for diffuse reflection laser ranging system. Based on the characteristics of time correlation for diffuse reflection laser ranging data, the extraction problem is simplified into npoints searching problem. Next, the correctness of the extraction based on time correlation is verified. And the rules to select a propernare given further through the trade-off between search cost and extraction accuracy. Then, the evaluation criteria for short-time linearity and adjacent similarity are given in detail. Finally, Genetic algorithm is adopted to realize parallel search for buffer data and online data, decreasing the search time as well as increasing the extraction accuracy of ranging data. The echo extraction for Yunnan Station's experimental data show that the extraction method proposed has strong ability to extract echo signal from high noise background quickly, which provides a feasible way to realize the signal online extraction for diffuse reflection laser ranging. © 2015, Chinese Optical Society. All right reserved.

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