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Angular velocity determination of spinning solar sails using only a sun sensor

Chinese Journal of Aeronautics 2017年第1期30卷 412-418页

作者： Zhai Kun School of Aerospace Engineering Tsinghua University Beijing 100084 China

The direction of the sun is the easiest and most reliable observation vector for a solar sail running in deep space exploration. This paper presents a new method using only raw measurements of the sun direction vector to estimate angular velocity for a spinning solar sail. In cases with a constant spin angular velocity, the estimation equation is formed based on the kinematic model for the apparent motion of the sun direction vector; the least-squares solution is then easily calculated. A performance criterion is defined and used to analyze estimation accuracy. In cases with a variable spin angular velocity, the estimation equation is developed based on the kinematic model for the apparent motion of the sun direction vector and the attitude dynamics equation. Simulation results show that the proposed method can quickly yield high-precision angular velocity estimates that are insensitive to certain measurement noises and modeling errors.

关键词： Condition number Least-squares method Solar sail Spinning velocity determination

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Instantaneous velocity determination and positioning using Doppler shift from a LEO constellation

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Satellite Navigation 2023年第1期4卷 28-40,I0002页

作者： Fei Guo Yan Yang Fujian Ma Yifan Zhu Hang Liu Xiaohong Zhang School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China Hubei Luojia Laboratory Wuhan 430079China Institute of Telecommunication and Navigation Satellites China Academy of Space TechnologyBeijingChina

To provide backup and supplementation for the Global Navigation Satellite System(GNSS),Doppler shift from Low Earth Orbit(LEO)satellites can be used as signals of opportunity to provide positioning,navigation,and timing *** this contribution,we frst investigate the model and performance of instantaneous velocity determination and positioning with LEO *** a LEO constellation with 288 satellites,we simulate Doppler shift observations at nine multi-GNSS experiment *** to the lower orbit,the performance of LEO velocity determination is much more sensitive to the initial receiver position error than that of *** results show that with the initial receiver position error increased from 0.1 to 10 m,the Root Mean Square Errors(RMSEs)increase from 0.73 to 2.65 cm/s,0.68 to 2.96 cm/s,and 1.67 to 4.15 cm/s in the east,north,and up directions,*** performances with GPS are compared with GPS+LEO,and it is found that LEO Doppler shift observations contribute to GPS velocity *** for LEO Doppler positioning,even if more than 30 visible LEO satellites are available,the position dilution of precision values can reach several *** that the error of LEO Doppler measurements is 0.01 m/s,the instantaneous Doppler positioning accuracy can achieve about a few meters,which is comparable to that of GNSS pseudorange positioning.A constant velocity model is adopted for state *** LEO Doppler positioning results show that an accuracy at centimeter to decimeter level can be achieved after solution *** a static simulated kinematic positioning test,the RMSEs range from a few decimeters to several meters in diferent regions by giving diferent *** a dynamic positioning test,the RMSEs are about 2–3 m in high latitude region.

关键词： Low earth orbit(LEO) GNSS Doppler shift velocity determination Instantaneous Doppler positioning

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Fast Position and velocity determination for Pulsar Navigation Using NML and LSM

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Chinese Journal of Electronics 2017年第6期26卷 1325-1329页

作者： LIU Jin WU Jin XIONG Ling FANG Jiancheng LIU Gang College of Information Science and Engineering Wuhan University of Science and Technology School of Instrumentation Science and Opto-electronics Engineering Beihang University

To reduce the computational cost, a Fast position and velocity joint determination(FPVD) method based on the Near-maximum likelihood(NML) and the Least square method(LSM) is proposed for X-ray pulsar navigation. Considering the fact that the Doppler effects caused by the velocity of the spacecraft alters the X-ray pulse Time-of-arrival(TOA), we adopt the NML to obtain multi-TOAs, and then utilize the LSM to estimate the variation of TOAs instead of the pulsar profile distortion adopted by the Maximum-likelihood(ML) estimation method. Finally, according to the variation value and TOAs, the position and velocity information of the spacecraft are calculated. The simulation results have demonstrated that the FPVD method is far faster than the ML estimation method, and its accuracy approaches the CramerRao lower bound(CRLB).

关键词： velocity determination Pulsar Maximum likelihood Least square method

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Low-cost Receiver Robust-RTD Algorithm Based on the Constraints of velocity

Low-cost Receiver Robust-RTD Algorithm Based on the Constrai...

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第九届中国卫星导航学术年会

作者： Jian Zhang Guorong Yu Shuguo Pan Guoliang Liu Fei Shen School of Transportation Southeast University School of Instrument Science and Engineering Southeast University

The improvement of low-cost receiver performance and the development of Multi-GNSS will make high-precision dynamic positioning, which is for the general public, become the main growth point of GNSS applications gradually. However, under the complex road conditions of the city, there are apparent facts that seriously affect the continuity and reliability of GNSS positioning, like satellite occlusion, the multi-path effects and so on, and restrict the rapid development of GNSS mass navigation. In this paper, based on the static and dynamic data of dual system(GPS + BDS) acquired by ublox M8 T module and ordinary ceramic patch antenna, an algorithm of phase smoothed pseudorange is used to improve the accuracy of pseudorange observations, the speed and direction of the receiver are constrained by doppler observations. The joint pseudorange and velocity pseudo-observations are used to establish the robust kalman filter for real-time dynamic positioning. The experimental results show that the proposed algorithm can guarantee the fast and reliable positioning of the low-cost receiver, under the open environment, the sub-meter level positioning accuracy can be basically achieved, and the reliable positioning within 2 m can be guaranteed effectively;in the complex environment, the positioning accuracy within 5 m can also be basically guaranteed.

关键词： Low-cost Robust Kalman RTD velocity determination

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