Beijing Huahang Radio Measurement Institute

Beijing, China

Beijing Huahang Radio Measurement Institute

Beijing, China
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Dai X.,Beijing Jiaotong University | Yuan X.,Beijing Jiaotong University | Zhang J.,Chinese Naval Aeronautical Engineering Academy | Zhang L.,Beijing Huahang Radio Measurement Institute
Proceedings of 2016 IEEE Advanced Information Management, Communicates, Electronic and Automation Control Conference, IMCEC 2016 | Year: 2016

Vehicle detection has been applied in many fields, such as intelligent transportation, video surveillance, driving assistance system and so on. In the case of fine weather, the state-of-the-art vehicle-detection systems may achieve good performance. However, the performance has a substantial decline in bad weathers, such as fog, night and so on. Therefore, improving the performance of vehicle-detection systems in different weather conditions becomes an important issue in vehicle-detection system. In the fog or night, the quality of the images is reduced. In this paper, we propose some algorithms of image defogging and color enhancement in order to improve the performance of vehicle detection. The result of vehicle detection get much better after image processing in bad weathers. © 2016 IEEE.

Le G.,Beijing Jiaotong University | Yuan X.,Beijing Jiaotong University | Zhang J.,Chinese Naval Aeronautical Engineering Academy | Li H.,Beijing Huahang Radio Measurement Institute
Proceedings of 2016 IEEE Advanced Information Management, Communicates, Electronic and Automation Control Conference, IMCEC 2016 | Year: 2016

The local features or the inner information of the signs are used in the most traffic sign recognition(TSR) systems for recognition. Such as histograms of oriented gradients (HOG), local binary pattern histogram (LBP), scale-invariant feature transform (SIFT), and so forth. However these features in the treatment of the rotation, strongly illumination, and deformation situations still has limitations. In this paper, we have made use of PCANet, as known as a simple unsupervised convolutional deep learning network for TSR system. The contributions of this paper are as follows: 1) we utilize the PCANet for TSR on the CTSRB database; 2) we analyze the impact of various parameters in PCANet. Experimental results on validating the effectiveness of the PCANet with traffic sign recognition system are satisfying, even for containing rotation, deformation, or images taken under different illumination situation. PCANet is very effectively in extracting useful information for classification of traffic sign images. © 2016 IEEE.

Feng F.,Beijing Huahang Radio Measurement Institute | Xu J.M.,Beijing Huahang Radio Measurement Institute | Ma J.T.,Beijing Huahang Radio Measurement Institute | Liu Z.L.,Beijing Huahang Radio Measurement Institute
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2017

We analyze the influence factors that affect the observed degree of squeezing in generation and detection stages theoretically, including the fluctuations of pump power, the intra-cavity loss of the optical parametric amplifier (OPA) cavity, the phase fluctuation on balanced homodyning stage, the propagation efficiency, the mode matching efficiency, the out-put mirror transmission of the OPA cavity and the quantum efficiency of the detector. The theoretical results show that different loss sources appearing at various stages of the squeezed light generation and detection are far more dominant and in the end limit the squeezing level achievable. The analysis of these parameters will be extremely useful for subsequent experiments. © 2017 SPIE.

Xu J.M.,Beijing Huahang Radio Measurement Institute | Hu S.Y.,Beijing Huahang Radio Measurement Institute | Feng F.,Beijing Huahang Radio Measurement Institute | Ma J.T.,Beijing Huahang Radio Measurement Institute | Liu Z.L.,Beijing Huahang Radio Measurement Institute
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2017

In this paper, we present an auto-focusing and ranging method which is based on light-field imaging spatial refocusing principles and simulation algorithm. The clearest image could be chosen among the refocused image sequences by using image-resolution evaluation functions when we select the window of the object whose distance needs to be measured. Finally, we measure an object on the scene with the auto-focusing and ranging method and analyze its range and accuracy. The experimental results show that the auto-focusing and ranging method could obtain distance information of different objects using one-shooting light-field image and then measure the distances of two or more objects in one scene. © 2017 SPIE.

Cheng J.,Harbin Engineering University | Li M.,Harbin Engineering University | Li M.,Beijing Huahang Radio Measurement Institute | Guan D.,Harbin Engineering University | And 2 more authors.
Journal of Computational and Theoretical Nanoscience | Year: 2017

Single-axis rotation inertial navigation system (SRINS) does not have the ability to achieve the modulation of all error sources of inertial navigation system (INS) by rotation. This would cause the problem that the residual error sources of SRINS will cause the navigation errors to accumulate over time, and lead to further evident nonlinear characteristics. Therefore, the traditional linear filter is unable to achieve the optimal estimation for the nonlinear error models any more. As the problem arise when the linearization of error models and linear filters are applied in nonlinear comprehensive calibration, this paper innovatively applies unscented Kalman filter (UKF) to SRINS by introducing the external position reference, and achieves the comprehensive calibration method of nonlinear filter estimation. Besides the nonlinear characteristic, the most important problem for the calibration is how to shorten the estimation time because of the poor observability of the azimuth gyroscope drift. Therefore, the modified UKF is designed to enhance the filter stability by introducing Qk, meanwhile guaranteeing accuracy of states estimation. The nonlinear comprehensive calibration of SRINS could be achieved by resetting navigation information, and the working cycle of SRINS is prolonged to satisfy long term position endurance. Simulation results show that the position endurance levels are compatible with 0.8 nmile/24 h, which means that this method can realize the comprehensive calibration, and verify the effectiveness and feasibility of the calibration algorithm. © 2017 American Scientific Publishers All rights reserved.

Feng F.,Beijing Huahang Radio Measurement Institute | Xu J.-M.,Beijing Huahang Radio Measurement Institute | Ma J.-T.,Beijing Huahang Radio Measurement Institute | Liu Z.-L.,Beijing Huahang Radio Measurement Institute | Zhang W.-J.,Beijing Huahang Radio Measurement Institute
Guangzi Xuebao/Acta Photonica Sinica | Year: 2017

The simulations of the noise distribution of vacuum state, single photon state and squeezed state in phase space were presented by Wigner function, respectively and the technology of the quantum lidar based on the squeezed field was systematically analyzed, including quantum coherent lidar and quantum lidar with squeezed light injection. Compared to the classical lidar, a higher squeezing degree benefits improvement of the detection Signal-To-Noise Ratio (SNR) for quantum coherent lidar, and a squeezing degree of 8dB would afford a 6.25-fold improvement in SNR theoretically, while the quantum lidar with squeezed vacuum injection has higher spatial resolution, which depends on the squeezing level of the squeezed vacuum and the gain of the phase sensitive amplifier. The results show that the quantum lidar has obvious advantages in the fields of weak signal detection and high-resolution imaging as the improvements of the signal-to-noise by using squeezed light. © 2017, Science Press. All right reserved.

Wu X.,Beihang University | Wu S.,Beihang University | Xing Z.,Beihang University | Zhang W.,Beijing Huahang Radio Measurement Institute
Proceedings of the 2015 27th Chinese Control and Decision Conference, CCDC 2015 | Year: 2015

The problem of seeker allocation and target assignment (SATA) of multiple hetero-seeker missile formation in the anti-ship cooperative attack was investigated in this paper. A calculation model of penetration probability and a model of SATA for the missile formation attack were designed, considering the characteristics of the missile seeker, the operational process of the missile formation cooperative attack, the shipboard anti-missile weapons with the constraints of the ammunition restrictions and the target value. Then a method based on genetic algorithms (GA) was presented, with novel encoding, modified initialization, crossover and mutation operations. Simulations demonstrate the viability of the proposed method, showing that the missile formation penetration probability increases by 10% using the proposed algorithm; it could provide basis and reference for actual combat operation. © 2015 IEEE.

Chen C.,Harbin Institute of Technology | Zheng Y.,Beijing Huahang Radio Measurement Institute | Hu S.-Y.,Beijing Huahang Radio Measurement Institute | Qiang W.-Y.,Harbin Institute of Technology
Yuhang Xuebao/Journal of Astronautics | Year: 2011

Frequency agility and coherent process technique used in radar are combined. In this context, the phase changes of the moving target echo are analyzed. Factors affecting the coherent include two coupling terms, carrier frequency versus range and carrier frequency versus velocity. Effective coherent methods on phase compensation are proposed, which include the irregular pulse repetition interval method and the cost-function based compensation method. The feasibility and versatility of this method are verified.

Jia X.,Harbin Institute of Technology | Zhao C.,Beijing Huahang Radio Measurement Institute
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2011

In modern tactical missiles terminal guidance system, strap-down stable scheme is prior to traditional gyro stable scheme in cost and volume, and is a new direction of missile seekers. The critical technique of strap-down terminal guidance system is the so called mathematical stabilization platform and strap-down stable control algorithm. The stabilization control scheme and guidance information extract approach of terminal guidance system with a semi-strap-down structure were discussed. A practical mathematical stabilization control algorithm and the relevant line of sight (LOS) angle rate extract method were devised, which was suitable for engineering implementation. First of all, the principle of strap-down stabilization control was discussed. After that, a new control law of the mathematical platform was described, together with a calculation algorithm of guidance information such as LOS angle and LOS angle rate. Moreover, in order to overcome the deficiency of calculation precision caused by imprecision of sensor's measurement and non-ideality of differential operation, a practical evaluation filter model of LOS angle rate was given out based on the angle tracking model of a missile to a target. Finally, computer simulations were made which verified the efficiency of above methods.

Huang P.,Xidian University | Liao G.,Xidian University | Yang Z.,Xidian University | Xia X.-G.,Xidian University | And 3 more authors.
IEEE Transactions on Signal Processing | Year: 2016

In the airborne or spaceborne radar applications, prolonging the coherent integration time is one of the effective methods to improve the radar detection ability of a weak maneuvering target, whereas the coherent integration performance may degrade due to the complex range migration (RM) and Doppler frequency migration (DFM) effects. In this paper, detection and motion parameter estimation for a weak maneuvering target with the third-order RM and DFM are considered. Firstly, Keystone transform is applied to compensate the linear range walk. Then, the matched filtering processing is performed in the range-frequency and azimuth-time domain to eliminate the residual coupling effects between range and azimuth. Finally, a well-focused image of a moving target is obtained, and three motion parameters, i.e., velocity, acceleration, and acceleration rate, are effectively estimated. In addition, as for a fast-moving target with Doppler ambiguity, two cases, i.e., target azimuth spectrum within a pulse repetition frequency (PRF) and spanning over neighboring PRF bands, are analyzed. Compared with the generalized Radon Fourier transform (GRFT), the proposed method can acquire a close integration performance but with lower computational complexity since the parameter searching dimension is reduced. Simulated processing results are provided to validate the effectiveness of the proposed method. © 1991-2012 IEEE.

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