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Fast BSC-based algorithm for near-field signal localization via uniform circular array

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Journal of Systems Engineering and Electronics 2022年第2期33卷 269-278页

作者： SU Xiaolong LIU Zhen SUN Bin WANG Yang CHEN Xin LI Xiang College of Electronic Science and technology National University of Defense TechnologyChangsha 410073China Beijing Institute of Tracking and Telecommunication Technology Beijing 100094China

In this paper,we propose a beam space coversion(BSC)-based approach to achieve a single near-field signal local-ization under uniform circular array(UCA).By employing the centro-symmetric geometry of UCA,we apply BSC to extract the two-dimensional(2-D)angles of near-field signal in the Van-dermonde form,which allows for azimuth and elevation angle estimation by utilizing the improved estimation of signal para-meters via rotational invariance techniques(ESPRIT)algorithm.By substituting the calculated 2-D angles into the direction vec-tor of near-field signal,the range parameter can be conse-quently obtained by the 1-D multiple signal classification(MU-SIC)method.Simulations demonstrate that the proposed al-gorithm can achieve a single near-field signal localization,which can provide satisfactory performance and reduce computational complexity.

关键词： near-field signal uniform circular array(UCA) beam space conversion(BSC) improved estimation of signal parame-ters via rotational invariance techniques(ESPRIT) 1-D multiple signal classification(MUSIC) parameter estimation

Robust reinforcement learning with UUB guarantee for safe motion control of autonomous robots

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Science China(Technological Sciences) 2024年第1期67卷 172-182页

作者： ZHANG RuiXian HAN YiNing SU Man LIN ZeFeng LI HaoWei ZHANG LiXian School of Astronautics Harbin Institute of TechnologyHarbin 150001China School of Management Harbin Institute of TechnologyHarbin 150001China Beijing Institute of Tracking and Telecommunication Technology Beijing 100094China

This paper addresses the issue of safety in reinforcement learning(RL)with disturbances and its application in the safety-constrained motion control of autonomous robots.To tackle this problem,a robust Lyapunov value function(rLVF)is proposed.The rLVF is obtained by introducing a data-based LVF under the worst-case disturbance of the observed state.Using the rLVF,a uniformly ultimate boundedness criterion is established.This criterion is desired to ensure that the cost function,which serves as a safety criterion,ultimately converges to a range via the policy to be designed.Moreover,to mitigate the drastic variation of the rLVF caused by differences in states,a smoothing regularization of the rLVF is introduced.To train policies with safety guarantees under the worst disturbances of the observed states,an off-policy robust RL algorithm is proposed.The proposed algorithm is applied to motion control tasks of an autonomous vehicle and a cartpole,which involve external disturbances and variations of the model parameters,respectively.The experimental results demonstrate the effectiveness of the theoretical findings and the advantages of the proposed algorithm in terms of robustness and safety.

关键词： motion control reinforcement learning robustness stability

Availability evaluation model for space-based optical aerial target detection system

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Optoelectronics Letters 2023年第10期19卷 599-604页

作者： ZHAO Jiaqing ZHANG Lei DING Xiang XU Zhongchao FAN Shiwei LIU Rongke Beijing Institute of Tracking and Telecommunication Technology Beijing100094China Shanghai Aerospace Electronic technology Research institute Shanghai201109China Beihang University Beijing100191China

For space-based optical detection systems,there is usually a difference between actual on-orbit operational performance and designed requirements based on fixed scenarios.To assess the availability of space-based optical detection systems in different backgrounds,the radiation characteristics of aerial targets have been simulated using body radiation and atmospheric transmission models.The background radiation characteristics were also statistically analyzed.Then,for the parameters of the fixed space-based optical detection system,the signal-to-clutter and availability were evaluated under different conditions.A linear relationship between the radiation intensity and the flight height of the target was obtained.For a space-based optical detection system,the analytical availability model was constructed.Finally,multiple groups of data under different simulation conditions were used to validate the universality and reliability of the model.This availability model could significantly reduce the time required to predict the availability of the space-based optical detection system.The model was also adopted to analyze the influence of flight height,mean and variance,and background clutter on the space-based optical detection availability.

关键词： optical system space

Study on the influence of antenna arrays anti-jamming algorithms on GNSS receiver single point position

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Study on the influence of antenna arrays anti-jamming algori...

第十四届中国卫星导航年会

作者： Yaoding Wang Si Chen Yuzhuo Hou Chengeng Su Beijing Institute of Tracking and Telecommunication Technology

GNSS has been widely used in military,aviation and other fields due to its high precision and wide coverage.However,GNSS signal is so weak that it is susceptible to interference.The antenna arrays anti-jamming algorithms are effective methods to enhance the robustness of the GNSS receiver single point position.According to whether the steering vector of the GNSS signal is needed,the algorithms are generally divided into two categories,i.***.minimum variance distortion less response(MVDR) algorithm and power inversion(PI) algorithm.Both of those two algorithms can implement null steering in the interference direction to suppress interference.The former needs the steering vector of the GNSS signal and can implement beamforming steering in the GNSS signal direction while the latter does not.The cost of those two anti-jamming algorithms is the introduction of pseudo-code measurement error.In this study,the principle of pseudo-code measurement error introduced by those two algorithms is analyzed.Several experiments are implemented to evaluate the pseudo-code measurement errors introduced by those two algorithms when the GNSS signal parameters and the inference signal parameters vary.Results show that-5 meters to 5 meters errors are introduced into the pseudo-code measurement for the PI algorithm when the GNSS and the interference signal parameters vary.For the MVDR algorithm,the pseudo-code measurement errors are smaller than those of PI algorithm.Receiver single point position(SPP) is tested using real BDS observations and simulated pseudo-code measurement errors introduced by those two algorithms.Results show that several meters level position errors are introduced into the receiver SPP.

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Influence of Inter-Satellite Link Geometry on Orbit Determination Accuracy for BDS-3

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Influence of Inter-Satellite Link Geometry on Orbit Determin...

第十三届中国卫星导航年会

作者： Chengeng Su Gong Zhang Jun Lu Beijing Institute of Tracking and Telecommunication Technology institute of telecommunication and Navigation Satellites CAST

Two-way ranging and communication between satellites by inter-satellite link（ISL） is an important innovative design of BDS-3, which can make up for the disadvantage of regionally distributed network and realize the tracking and measurement for the whole arc of navigation satellites. By introducing ISL measurements into orbit determination processing, the orbit accuracy can be effectively improved. The influence of ISL measurement geometry on satellite orbit determination accuracy is evaluated. Taking the post-processed satellite orbit solutions provided by IGS as references, the orbit accuracy of BeiDou satellites under different conditions is evaluated. The results show that in the case no ISL measurements, the user ranging error（URE） of satellite orbit is about 0.3 m. With all ISLs used, the orbital URE is below 0.08 m. Then, the influence of the number of the ISLs on orbit determination accuracy is further investigated. The results show that when the number of ISLs between satellites is reduced by 17%, 24% and 40%, respectively, the accuracy loss of orbit in radial component is only at millimeter level, and the loss in tangential and normal component is at centimeter level, thus the accuracy loss can be neglected. Even if a satellite has only two ISLs, the orbital URE is only increased to 12 cm, which indicates that the satellite orbit can still maintain relatively high accuracy in the case of only a few links. This provides a reference for the operator to formulate the plan of ISL.

关键词： BDS Inter-satellite link Joint orbit determination User ranging error

Precession–nutation correction for star tracker attitude measurement of STECE satellite

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Chinese Journal of Aeronautics 2014年第1期27卷 117-124页

作者： Lai Yuwang Liu Junhong Ding Yonghe Gu Defeng Yi Dongyun Department of Mathematics and Systems Science National University of Defense Technology Beijing Institute of Tracking and Telecommunication Technology

Space technology Experiment and Climate Exploration （STECE） is a small satellite mis- sion of China for space technology experiment and climate exploration. A new test star tracker and one ASTRO 10 star tracker have been loaded on the STECE satellite to test the new star tracker＇s measurement performance. However, there is no autonomous precession nutation correction func- tion for the test star tracker, which causes an apparent periodic deflection in the inter-boresight angle between the two star trackers with respect to each other of up to - 500 arcsec, so the preces- sion and nutation effect needs to be considered while assessing the test star tracker. This paper researches on the precession-nutation correction for the test star traeker＇s attitude measurement and presents a precession-nutation correction method based on attitude quaternion data. The peri- odic deflection of the inter-boresight angle between the two star trackers has been greatly eliminated after the precession and nutation of the test star tracker＇s attitude data have been corrected by the proposed method and the validity of the proposed algorithm has been demonstrated. The in-flight accuracy of the test star tracker has been assessed like attitude noise and low-frequency errors after the precession-nutation correction.

关键词： Attitude determination Low-frequency periodicerror Precession-nutation Star trackers STECE satellite

Research on an Artificial Intelligence Based Diagnosis Algorithm of Plough Satellite Telemetry Anomaly

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Research on an Artificial Intelligence Based Diagnosis Algor...

第十四届中国卫星导航年会

作者： Lu Wang Lei Chen Jian Wang Huiyan Zhao Bohao Cui Yueyang Sun institute of telecommunication and navigation satellite CAST Beijing Institute of Tracking and Telecommunication Technology beijing University of Posts and telecommunications

The traditional satellite telemetry data anomaly detection method based on threshold interpretation and expert knowledge base has the characteristics of a wide diagnostic threshold range and large constraint by experience, and the accuracy of the decision results cannot fully meet the application requirements of high reliability of navigation satellites. Therefore, it is urgent to develop an automatic system for satellite anomaly detection. In this work, the Auto-Encoder algorithm(AE) and Prophet algorithm are applied to Plough navigation satellite telemetry anomaly detection and prediction for the first time, and typical satellite anomaly telemetry mode is selected for analysis and verification. The result shows that the satellite’s abnormal fluctuation trend predicted by the Prophet algorithm is consistent with the actual data abnormal distribution. This algorithm can support accurate satellite anomaly detection, it can correctly predict the changing trend of satellite telemetry data and ensure the effectiveness of anomaly detection. It will be of great significance for the timely and effective diagnosis of satellite system telemetry data anomalies in the future and can support the use of engineering in orbit.

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Research on Development and Analysis of Miniaturized Antenna for GNSS High-precision Applications

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Research on Development and Analysis of Miniaturized Antenna...

第十三届中国卫星导航年会

作者： Ji Guo Tian Wang Weiguang Gao Xia Chen Shanbin Shi Kai Wang Beijing Institute of Tracking and Telecommunication Technology beijing Orient institute of Measurement and Test

As an essential base component, thehigh-precision antenna has an important impact on the quality of the signal. The performance ofhigh-precision antenna is a key factor in determining the performance indicators of satellite navigation terminals. This article proposed small-scalarized antennas for high-precision applications. Toward the flat antenna and cylindrical antenna, the study on the miniaturization of multi-band active circuits is introduced. It solved contradictions between multi-band combination and antenna size miniaturization. Through simulation and analysis, we found a composite radiator is formed by adding the coupling ring around the double layer 3 D microstrip antenna. And the stereo radiator is formed, with the coupling ring around the top microstrip antenna linked with the patch surface of the underlying 3 D microstrip antenna. Those can effectively broaden the antenna gain of 3 dB beam width（GBW）, and axial ratio of 3 dB beam width（ARBW）, with increasing the low elevation gain. Accordingly, thoseantennas can provide good gain properties under smaller dimensions.

关键词： High-precision GNSS Miniaturized antenna Gain

Robust Alignment Base on IKF for SINS/DVL Integrated Navigation System

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Robust Alignment Base on IKF for SINS/DVL Integrated Navigat...

第十四届中国卫星导航年会

作者： Jingshu Li Bing Zhu Ge Tian Zuohu Li De Jiang Xia Guo Naval University of Engineering Beijing Institute of Tracking and Telecommunication Technology

SINS is the main navigation means for AUV, which is mainly composed of SINS, DVL and acoustic transponder. Due to the advantages of strong autonomy, high accuracy and strong stabilization of velocity measurement with time, DVL can realize all-time and all-weather autonomous navigation when being integrated with SINS. In SINS/DVL integrated autonomous navigation underwater, the measured data of DVL are easily polluted by non-Gaussian noise such as outliers. The priori information of state quantity is usually unknown and the value is also hard to estimate accuracy enough, which will lead performance of alignment to decline or even divergent. To solve the above problems, a RIKF alignment method based on Mahalanobis distance(MD) with an expansion factor weighting is proposed in this paper. The effectiveness of the proposed RIKF is verified by the data measured from the SINS/DVL on board. Initial alignment experiments are carried out by traditional KF, IKF and RIKF algorithm respectively under the conditions of DVL being polluted by outliers noise. Compared with KF and IKF, the results show that the proposed RIKF algorithm have a better performance with the measured data polluted by outliers, and RIKF algorithm is feasible and effective to be applied to the dynamic initial alignment of SINS/DVL integrated system.

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