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Liu Y.,Beihang University | Zhu Y.,Aviation Data Communication Corporation
Institute of Navigation International Technical Meeting 2014, ITM 2014 | Year: 2014

Outlier detection and isolation is critical for aviation navigation. For GNSS, outlier occurred in SIS segment is dominant to lead positioning failure. This paper proposes a historical data based methodology for the analysis of SIS range outliers. Historical SIS outliers are collected by comparing broadcasted ephemeris with precision ephemeris provided by IGS. SIS range outliers are computed around China's airspace. Both the spatial and temporal characteristics of outliers are carefully discussed. Outlier duration, magnitude and influenced area are considered as the most important parameters for the outlier pool establishment. The relationship between outliers and influenced aviation phase of LPV200 is also studied, with ICAO'S required navigation performance as criteria. Ten years' GPS data is used for experiments. The results show that temporal outliers are closely related to the outlier duration, spatial outliers are mainly linked to the outlier magnitude. With year increases from 2002 to 2010, total number of ephemeris outliers decreases. What's more, ephemeris outliers have significant influence on LPV200 performance. When the magnitude of outlier is large enough, the 99.999% availability is hardly meet with by current technical framework. Our work is valuable not only for GNSS integrity performance assessment and also brings benefits to the development of enhance integrity monitor system in near future. Source


Li R.,Aviation Data Communication Corporation | Wang Y.,Beihang University | Zhang J.,Aviation Data Communication Corporation | Zhu Y.,Aviation Data Communication Corporation
Chinese Journal of Electronics | Year: 2010

Multi-mode satellite navigation receivers have to endure heavier computation load because of huge increment of visible satellites, in hybrid GPS, GLONASS, Galileo and Compass navigation scenario. To solve these problems, in the paper, two new technologies are presented to decrease computation load: Fast satellite selection algorithm (FSS) and Novel weighted least-squared positioning algorithm (NWLS). Different with conventional methods, FSS is based on satellite elevation and azimuth. Firstly, all visible satellites are classified by elevation, with three sections: low, medium and high elevation. Then, parts of satellites in medium elevation section are excluded through sorting, differencing, and ratio of high elevation satellites and low elevation satellites. As to NWLS positioning algorithm, ionosphere delay and other error are analyzed separately firstly; then weighted observation matrix is created according to two kinds error and satellite position. The matrix is employed in receiver position calculation. With satisfied positioning accuracy, FSS algorithm is able to decrease computation load by about 20-30%. In conclusion, FSS and NWLS algorithm are efficient and effective to decrease load of receiver; they are proper to integrated satellite navigation application scenario. Source


Liu Y.,Beihang University | Zhu Y.,Aviation Data Communication Corporation
Institute of Navigation International Technical Meeting 2014, ITM 2014 | Year: 2014

Safety is a critical issue for aviation. RAIM availability test is usually applied to insure safety service in civil aviation. At the same time, ability of airborne RAIM also requires enhancement to obtain high integrity performance. This paper proposes a flexible and easy-implementing multi-constellation RAIM algorithm based on airspace-ground cooperation. Supporting multi-constellation navigation, the proposed algorithm enables assessment of navigation measurement errors, and can provide multi-constellation RAIM availability for regional airspace to satisfy RNP for different phases of flight. To release calculation burden of aircraft, the algorithm is cascade implemented by three levels. Experiments were carried out for GPS/Beidou dual-constellation scenery. Compared with traditional RAIM, our algorithm performs superior with aspects of high failure detection probability, better integrity and availability. Source


Zhang J.,Beihang University | Liu W.,Aviation Data Communication Corporation | Zhu Y.,Beihang University
Chinese Journal of Aeronautics | Year: 2011

In western China, the terrain and meteorological conditions are so complex that it is not suitable to construct new radar stations. Automatic dependent surveillance-broadcast (ADS-B) is a totally new surveillance method, so before practically applied and operated in China, abundant tests and evaluations are necessary to validate the performance of ADS-B and guarantee the operational security. During the flight tests, we collect the data of radar, ADS-B and high accuracy position and compare the performance of ADS-B with radar based on high accuracy position. To solve the asynchronous problem among radar data, ADS-B data and real-time kinematic (RTK) data caused by different update rates, this article proposes the technique of synchronizing multi-surveillance data by extrapolating from the data of low update rate to high update rate according to velocity and heading. Meanwhile, because radar data, ADS-B data and RTK data are expressed in different coordinates and cannot be compared each other, this article provides a method to unifying the coordinates of multi-surveillance data. By the analysis and evaluation, we can conclude that the performance of ADS-B is better than radar. © 2011 Chinese Journal of Aeronautics All rights reserved. Source


Zhao S.,Beihang University | Fang J.,Aviation Data Communication Corporation | Ji X.,Beihang University
Proceedings of the World Congress on Intelligent Control and Automation (WCICA) | Year: 2015

In this article, the cellular automation model is used to solve the problem of double-runway aircraft landing scheduling. A virtual model for simulating the landing process is established based on the cellular automation (CA), and the object of the model is aimed at minimizing the total cost of aircraft landing sequence. The simulation results show that this algorithm is capable of achieving high-quality scheduling results. Meanwhile, the computing time can also be significantly reduced, which shows great efficacy and efficiency of our algorithm in the double-runway aircraft landing scheduling. © 2014 IEEE. Source

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