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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.


Xue L.,Beijing Institute of Technology | Xue L.,Key Laboratory of Space Object Measurement | Li M.,Beijing Institute of Technology | Li M.,Key Laboratory of Space Object Measurement | And 4 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2015

Avalanche photo diodes (APDs) are parallel connected in multi pixel photon counter (MPPC). The output pulse is distorted when photon arrival time gets closer, and discrete photon arrival time is unable to resolve. With photon distribution and output pulse considered, analytical form of discrete photon arrival time detected in laser ranging is derived with deconvolution from the output pulse. Also, ranging data size is increased, helpful for the recognition of efficient photons from noise. In the algorithm, single pulse response is approximated to Gaussian form, and effects of time jitter on photon discrimination are studied. Consumed the time jitter of pulse response is 50~250 ps, both statistical distribution histogram and the relation of peak-valley contrast, time interval and time jitter are obtained with three photons. Data sizes before and after deconvolution are compared in kHz laser ranging system during 1 s observation time. Results show discrete time is able to be resolved when peak-valley contrast is above 10 in histogram, and the discrimination time resolution is 0.2~0.7 ns. ©, 2015, Science Press. All right reserved.


Liu Y.,Science and Technology on Aerospace Flight Dynamic Laboratory | Liu Y.,China Aerospace Science and Technology Corporation | Zhao H.,Key Laboratory of Space Object Measurement | Cao J.-F.,Science and Technology on Aerospace Flight Dynamic Laboratory | And 5 more authors.
Journal of Beijing Institute of Technology (English Edition) | Year: 2015

Detection for systematical error is needed in navigation system for all instruments. A new method for systematical error real-time detection and estimation is proposed by theory of sparse optimization and UKF. In this method, a sparse optimization procedure is introduced for the systematical error detection at each filter time step. It has less risk of calibration delay and diversion of systematical error than traditional methods, which makes the error detection and the state estimation more accurate. According to the theory analysis and simulation results, the new method can solve state and systematical errors simultaneously by virtue of the effective error detection. Thus, the accuracy and reliability of navigation system with multi-sensor can be improved. © 2015 Beijing Institute of Technology.


Yuan Y.,Beijing Institute of Technology | Yuan Y.,Key Laboratory of Space Object Measurement | Zhao P.,Beijing Institute of Technology | Zhao P.,Key Laboratory of Space Object Measurement | And 4 more authors.
IEEE Communications Letters | Year: 2016

In this letter, we propose a hybrid maximum likelihood (HML) classifier for continuous phase modulation (CPM). To the best of our knowledge, the proposed likelihood function is the first one for CPM signals that is based on two of its main features: nonlinear waveform, which is represented with its principal components, and signal memory, which is modeled as a Markov mapping symbol sequence. Unknown channel parameters are estimated through the expectation-maximization (EM) algorithm. An approximation method is further proposed to ensure that the proposed classifier improves classification performance at the cost of a moderate increase in calculations. Numerical results prove the superiority of the proposed approach over the classical HML classifier and feature-based classifier in terms of classifying CPM and linear modulation. © 2016 IEEE.


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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