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High-precision magnetic field measurement system based on a coherent population trapping magnetometer onboard the SATech-01 satellite

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Science China Technological Sciences 2025年

作者： Hongbo XUE Wei SONG Haoran ZHAO Yiteng ZHANG Shanzhi YE Jindong WANG Ran TAO Peng SANG Keli CHEN Xingzi BI Bingjun CHENG Bin ZHOU Yongliang XUE Yingying TANG Liu LIU Jinsong LI Xiaocheng ZHU Baoquan LI Jinguo LIU Wen CHEN Xiaofeng ZHANG Yonghe ZHANG Lei LI State Key Laboratory of space Weather National Space Science Center Chinese Academy of Sciences Key Laboratory of Solar Activity and space Weather National Space Science Center Chinese Academy of Sciences Key Laboratory of Electronics and Information technology for space Systems National Space Science Center Chinese Academy of Sciences State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Innovation Academy for Microsatellites Chinese Academy of Sciences

On July 27, 2022, a high-precision system for measuring the magnetic field based on a coherent population trapping magnetometer（referred to as the CPT system） was launched onboard the space Advanced technology demonstration satellite（SATech-01） by a ZK-1A rocket. The payload comprises a scalar coherent population trapping magnetometer（CPTM）, triaxial anisotropic magnetoresistance magnetometer（AMRM）, and nano star tracker mounted on a non-magnetic telescopic tubular mast. This configuration enables synchronized measurement of scalar and vector geomagnetic fields, as well as the attitude,making the payload with its compact sensors suitable for applications on miniature satellite platforms. On November 7, 2022,the novel telescopic tubular mast was deployed in orbit, extending to a length of 5.28 m. The CPTM, an absolute scalar magnetometer with an omnidirectional sensor, is the first China-developed quantum/atomic magnetometer successfully operating in space. In orbit, the CPTM has sensitivity of ～10 pT/Hz1/2and can automatically operate under complex magnetic field variations. The difference between the scalar fields obtained using the CPTM and CHAOS model has a mean deviation of–3.73 n T and a standard deviation of 26.11 nT（1σ）, without on-orbit calibration or correction. The miniaturized AMRM has a sensitivity of ～0.3 n T/Hz1/2and maintains stable and reliable operation in orbit. The low-power and miniaturized nano star tracker has a measurement uncertainty of 14.23″（1σ） in orbit. The mission has realized the on-orbit technical verification of the integrated and synchronized detection of the vector magnetic field and attitude and fully validated the system's performance,automation level, and reliability.

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A Hybrid Compression Framework for Large Scale Trajectory Data in Road Networks

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Chinese Journal of Electronics 2015年第4期24卷 730-739页

作者： WU Peili TAN Yu'an ZHENG Jun ZHANG Quanxin LI Yuanzhang CHENG Zijing School of Computer Science and technology Beijing Institute of Technology space star technology CO. Ltd China Academy of space technology

A Hybrid compression framework of trajectory data(HCFT) is proposed for effective compression of tra jectory data with road network limited. It’s different from the present researches which mainly focus on compression of single tra jectory, and further takes data redundancy raised by the similarity of movement pattern of moving objects into consideration. HCFT divides the redundancy of tra jectory data into Single tra jectory redundancy(STR) and Multiple tra jectories redundancy(MTR) and compresses them in a hybrid way(i.e. synchronous compression for STR at first and then asynchronous compression for MTR). We propose an asynchronous extraction algorithm for MTR based on frequent Road track subsequence(RTS), which replaces similar movement route by RTS, with the complexity of calculation significantly reduced. HCFT can not only gain higher compression ratio,but also ensure effectiveness of compressed tra jectory. We also verify effectiveness and superiority of the new method according to the experiments of real tra jectory dataset.

关键词： Trajectory data Movement similarity Road track Dictionary coding Multi-tra jectories compression

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Observer-based adaptive sliding mode backstepping output-feedback DSC for spin-stabilized canard-controlled projectiles

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Chinese Journal of Aeronautics 2017年第3期30卷 1115-1126页

作者： Yuanchuan SHEN Jianqiao YU Guanchen LUO Xiaolin AI Zhenyue JIA Fangzheng CHEN School of Aerospace Engineering Beijing Institute of Technology space star technology Co. Ltd

This article presents a complete nonlinear controller design for a class of spin-stabilized canard-controlled *** ultimate boundedness and tracking are achieved,exploiting a heavily coupled,bounded uncertain and highly nonlinear model of longitudinal and lateral *** order to estimate unmeasurable states,an observer is proposed for an augmented multiple-input-multiple-output（MIMO） nonlinear system with an adaptive sliding mode term against the *** the frame of a backstepping design,an adaptive sliding mode output-feedback dynamic surface control（DSC） approach is derived recursively by virtue of the estimated *** DSC technique is adopted to overcome the problem of ‘‘explosion of complexity＂ and relieve the stress of the guidance *** is proven that all signals of the MIMO closed-loop system,including the observer and controller,are uniformly ultimately bounded,and the tracking errors converge to an arbitrarily small neighborhood of the *** results for the observer and controller are provided to illustrate the feasibility and effectiveness of the proposed approach.

关键词： Backstepping Dynamic surface control technique Nonlinear systems Observers Sliding mode control Spin-stabilized canard controlled projectiles

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Study on Onboard Engine Thrust Estimation Based on GNSS Precision Orbit Determination technology

Study on Onboard Engine Thrust Estimation Based on GNSS Prec...

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第五届中国卫星导航学术年会

作者： Chen Shanshan Yue Fuzhan Jiang Yong Li Dongjun space star technology

ISBN: (纸本)9783642547362

Electric propulsion technology which has the advantages of high specific impulse, small thrust becomes the preferred way of space exploration in future. To ensure the safety and effectiveness of electric propulsion technology applications, the assessment of its performance is needed. The GNSS technology is now used for orbit determination, time service and so on, and it can be used for onboard thrust estimation. The paper gives the thrust model first. Then it gives the method to estimate the thrust for low and circle satellite orbit and the workflow using GNSS precision orbit determination technology. At last, the simulation is made to analyse the semi-major axis variation under the thrust in the velocity direction. The result of Grace real time orbit and precision orbit is also give to prove the validity of the method in paper. The paper puts forward a suggestion that the real time orbit determination technology can be used for onboard engine thrust rapid assessment.

关键词： Precision Orbit Determination GNSS Electric Thruster Real Time Orbit Determination

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Digital Watermarking Secure Scheme for Remote Sensing Image Protection

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China Communications 2020年第4期17卷 88-98页

作者： Guanghui Yuan Qi Hao space star technology co. LTDBeijing 100086China

As a means of copyright protection for multimedia data, digital watermarking technology has attracted more and more attention in various research fields. Researchers have begun to explore the feasibility of applying it to remote sensing data recently. Because of the particularity of remote sensing image, higher requirements are put forward for its security and management, especially for the copyright protection, illegal use and authenticity identification of remote sensing image data. Therefore, this paper proposes to use image watermarking technology to achieve comprehensive security protection of remote sensing image data, while the use of cryptography technology increases the applicability and security of watermarking technology. The experimental results show that the scheme of remote sensing image digital watermarking technology has good performance in the imperceptibility and robustness of watermarking.

关键词： data security watermark remote sensing image protection

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Time synchronization and ranging under unknown positions and velocities

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Science China(Technological Sciences) 2017年第2期60卷 271-281页

作者： GU XiaoBo CHANG Qing XU Yong WANG Dun School of Electronic & Information Engineering Beihang University space star technology Co. Ltd

The process to achieve time synchronization and ranging for a network of mobile nodes is raising a concern among researchers, and hence a variety of joint time synchronization and ranging algorithms have been proposed in recent years. However, few of them handle the case of all-node motion under unknown positions and velocities. This study addresses the problem of determining ranging and time synchronization for a group of nodes moving within a local area. First, we examined several models of clock discrepancy and synchronous two-way ranging. Based upon these models, we present a solution for time synchronization with known positions and velocities. Next, we propose a functional model that jointly estimates the clock skew, clock offset, and time of flight in the absence of a priori knowledge for a pair of mobile nodes. Then, we extend this model to a network-wide time synchronization scheme by way of a global least square estimator. We also discuss the advantages and disadvantages of our model compared to the existing algorithms, and we provide some applicable scenarios as well. Finally, we show that the simulation results verify the validity of our analysis.

关键词： time synchronization two-way ranging relative motion clock model joint estimation

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A regulated digital currency

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Science China(Information Sciences) 2019年第3期62卷 119-130页

作者： Yanbing WU Haining FAN Xiaoyun WANG Guangnan ZOU Institute for Advanced Study Tsinghua University Department of Computer Science and technology Tsinghua University space star technology Co. Ltd

The decentralized digital currency Bitcoin is an anonymous alternative to the centralized banking system and enjoys widespread and increasing adoption. Since Bitcoin created, many other electronic currencies have been developed. We propose a protocol for an electronic currency for making anonymous payments that can be supervised by an auditor, who has sole access to the transaction history. Other electronic currencies provide only anonymity, which is convenient for making illegal transactions without regulation. For users, miners, and banks, the transactions of our electronic currency are anonymous, and only auditors can see how it is used. We make use of POW(prove-of-work) technique that allows for distributed decisionmaking within a network, namely the Bitcoin blockchain protocol. We combine the POW and blockchain technology of Bitcoin to give better protection against double-spending attacks.

关键词： Blockchain Bitcoin anonymous digital currency regulated proof-of-work

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Null steering antenna beamforming utilizing space-time adaptive processing

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The Journal of China Universities of Posts and Telecommunications 2015年第4期22卷 51-55页

作者： Zeng Hao Ahmad Zeeshan Dong Tao Liu Ling School of Communications Engineering Chongqing University space star technology Co. Ltd

A new architecture of null steering antenna based upon the technology of space-time adaptive processing（STAP） with optimized parameters is proposed. The new STAP antenna is comprised of multiple channels and each channel is a transversal filter. So separate sensor element for the reference signal is not required because the antenna gets the reference signal from the first sensor of the auxiliary array. Furthermore, the least mean square（LMS） algorithm is employed to calculate the weight vector. Detailed analysis about the relationship between noise power and output error is investigated. Compared with the traditional null steering antenna in space or space-time domain, the new approach obtains more freedom degrees and can suppress both the wideband and narrowband interferences more efficiently with deeper nulls. Simulation results shows that the proposed architecture outperforms the conventional STAP techniques for interference suppression.

关键词： null steering antenna STAP beamforming interference mitigation

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The implementation of rapid acquisition algorithm for GPS weak signal by using FPGA

The implementation of rapid acquisition algorithm for GPS we...

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第五届中国卫星导航学术年会

作者： Wang yuanlei Gao yang Wang meng space star technology Co. Ltd

ISBN: (纸本)9783642547362

The traditional acquisition technology of low oribit GPS signal has been widely applied in the design of GPS navigation receiver. However, navigation receiver can only accept the navigation signal which comes from the other end of the earth when running above the navigation constellation, which results the decline of GPS navigation visibility and signal power , and the navigation signal power from high oribit navigation receiver will reduce 10dB at least than low oribit navigation receiver and traditional fast acquisition design can not meet design requirements of high oribit navigation receiver. Therefore, this paper present a design which increase times of coherent integration to improve ratio of carrier and noise of received signal, at the same time, it uses full link simulation by simulink to vertify feasibility of the design, the final design of weak signal acquisition, through the test of Xilinkcompany Virtex4 series FPGA chip based on the weak signal acquisition sensitivity up to -176dB. Because the GLONASS navigation system and BDS navigation and GPS navigation system using spread spectrum communication system, different with GPS navigation system in production of presucode ratio and presurange and the carrier frequence paramaters. Therefore, this fast acquisition algorithm for GPS weak signal adapt to the design of GLONASS navigation reciver and BDS navigation reciever.

关键词： GPS. Weak Signal. fast acquisition. High Orabit

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Construction of Type-II QC LDPC Codes Based on Perfect Cyclic Difference Set

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Chinese Journal of Electronics 2015年第1期24卷 146-151页

作者： ZHANG Lijun LI Bing CHENG Leelung School of Electronic and Information Engineering Beijing Jiaotong University space star technology Co. Ltd China Academy of Space Technology Department of Electronic Engineering City University of Hong Kong

Quasi-cyclic(QC) Low-density paritycheck(LDPC) codes are constructed from combination of weight-0(null matrix) and Weight-2(W2) Circulant matrix(CM), which can be seen as a special case of the general type-II QC LDPC codes. The shift matrix of the codes is built on the basis of one integer sequence, called perfect Cyclic difference set(CDS), which guarantees the girth of the code at least six. Simulation results show that the codes can perform well in comparison with a variety of other LDPC codes. They have excellent error floor and decoding convergence characteristics.

关键词： Type-II QC LDPC codes Weight-2 circulant matrix Perfect cyclic difference sets.

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