Time filter

Source Type

Liu Q.,China National Administration of GNSS and Applications | Tian S.,PLA University of Science and Technology
Proceedings of 2nd International Conference on Computer Science and Network Technology, ICCSNT 2012 | Year: 2012

The paper focuses on the Receiver Autonomous Integrity Monitoring (RAIM) performance of Compass augmentation using a proposed LEO satellite system. The Compass satellite system is briefly reviewed. RAIM algorithm is analyzed, in addition, the measurement equation in the joint Compass/LEO system is constructed. The RAIM performance is analyzed using the rates of fault detection and identification. Based on the authors' previous work, the performance of the augmented scheme is demonstrated through in-depth numerical simulations. Results show that the augmentation with LEO satellite system will improve the performance of RAIM. © 2012 IEEE. Source

Feng X.,China National Administration of GNSS and Applications | Wang H.,Xian Research Institute of Surveying and Mapping
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2011

In this paper, using narrow correlation and double delta correlation techniques, the running average of weighted multipath error envelope of BPSK(1) and BOC(1, 1) is simulated in different pre-correlation bandwidth and correlator spacing. The result shows that multipath performance becomes better when correlator spacing decreases, but it's not obvious when correlator spacing is 0.1 chip, and there is a least multipath error when pre-correlation bandwidth increases. Source

Huang G.,Changan University | Yang Y.,China National Administration of GNSS and Applications | Zhang Q.,Changan University
Acta Geodaetica et Cartographica Sinica | Year: 2011

Is proposed that a novel clock error estimation and prediction algorithm - adaptively robust sequential adjustment with classified adaptive factors based on opening windows. The main ideas are firstly one dimensional clock error series are processed to eliminate the gross errors with robust equivalence weight estimation in opening windows, where adaptive factors are used between windows to reduce the anomaly of clock errors. Secondly, as for the different satellite clocks, based on their different error characteristics, the classified adaptive factors are adapted to mitigate the effects form clock outliers. Tests indicate as for the fitting precision and prediction precision, the new proposed algorithm can improve 78. 9% and 60. 4% respectively by comparing with no robust estimation method. Besides, even for the robust estimation, classified factors method are better than single factor method, tests show about 4. 3% and 29. 2% improvement in fitting precision and prediction precision respectively. Source

Yang Y.,China National Administration of GNSS and Applications | Yang Y.,Xian Research Institute of Surveying and Mapping | Xu T.,Xian Research Institute of Surveying and Mapping
International Association of Geodesy Symposia | Year: 2015

The quality of kinematic positioning and navigation depends on the quality of the kinematic model describing the vehicle movements and the reliability of the measurements. A series of adaptive Kalman filters have been studied in recent years. The main principles of four kinds of adaptive filters are summarized, i.e. fading Kalman filter, adaptive Sage windowing filter, robust filter and adaptively robust filter. Some of the developed equivalent weight functions and the adaptive factors including the fading factors are also introduced. Some applications are mentioned. © Springer International Publishing Switzerland 2015. Source

Yang Y.,China National Administration of GNSS and Applications
Acta Geodaetica et Cartographica Sinica | Year: 2010

Satellite navigation has stepped into the era of a hundred flowers in bloom. The progress, application, contribution and challenges of Compass/Beidou satellite system is reviewed and analyzed. Firstly, the construction principles and development steps are Introduced. Secondly, the general realizations of signal frequency and the coordinate system as well as the time system of Beidou satellite navigation system In the frame of compatibility and interoperability are described. Thirdly, In the concept of redundancy, the main contributions of Beidou system are analyzed. At last, the applications and the main challenges of Beidou system are reviewed. Source

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