LM launch vehicles established a new record by successfully performing the 16th successful flight this year.A LM-3A launched the 10th BeiDou 2 satellite into its predetermined transfer orbit on December 2 from the XSL...LM launch vehicles established a new record by successfully performing the 16th successful flight this year.A LM-3A launched the 10th BeiDou 2 satellite into its predetermined transfer orbit on December 2 from the XSLC in Sichuan Province.展开更多
为确保船舶航行安全,利用北斗二代卫星导航技术,设计船载定位终端.该终端以S3C2440ARM处理器和Windows CE 6.0嵌入式系统为核心,以外围电路为辅,采用最小二乘算法,实现船舶的导航定位.通过MATLAB软件对可见卫星数目和水平精度因子进行...为确保船舶航行安全,利用北斗二代卫星导航技术,设计船载定位终端.该终端以S3C2440ARM处理器和Windows CE 6.0嵌入式系统为核心,以外围电路为辅,采用最小二乘算法,实现船舶的导航定位.通过MATLAB软件对可见卫星数目和水平精度因子进行计算和分析,论证方案的可行性和可靠性,进一步推动北斗船载终端在航行中的应用.展开更多
The BeiDou-2 satellite navigation system broadcasts triple frequency data. In this paper, the pseudorange multipath is extracted by using the geometry-free and ionosphere-free combination of one pseudorange and two ph...The BeiDou-2 satellite navigation system broadcasts triple frequency data. In this paper, the pseudorange multipath is extracted by using the geometry-free and ionosphere-free combination of one pseudorange and two phase measurements, and the phase multipath is extracted by using triple frequency phase measurements, respectively. By using several days’ static observation data, we exact the noisy pseudorange and phase multipath of three types of satellites, GEO, IGSO and MEO satellites. Because of the low frequency characteristics of the multipath, the low frequency wavelet filter is further used to recover the high-precision low frequency multipath signals that are specified by their amplitudes, periods and phases. The results show that the multipath periods are about 86160s, 86158s and 46391s for GEO, IGSO and MEO satellites, respectively, which coincide with that of the corresponding satellite orbits. Then we use the extracted multipath signals to correct the pseudorange measurements in order to improve the accuracy of point positioning. The positioning accuracy in East-West direction can be significantly improved by using the multipath corrected pseudorange measurements, and in the other two directions the positioning accuracy can also be improved to some extent.展开更多
The visibility for low earth orbit（LEO） satellites provided by the BeiDou-2 system is analyzed and compared with the global positioning system（GPS）. In addition, the spaceborne receivers＇ observations are simulat...The visibility for low earth orbit（LEO） satellites provided by the BeiDou-2 system is analyzed and compared with the global positioning system（GPS）. In addition, the spaceborne receivers＇ observations are simulated by the BeiDou satellites broadcast ephemeris and LEO satellites orbits. The precise orbit determination（POD） results show that the along-track component accuracy is much better over the service area than the non-service area, while the accuracy of the other two directions keeps at the same level over different areas. However, the 3-dimensional（3D） accuracy over the two areas shows almost no difference. Only taking into consideration the observation noise and navigation satellite ephemeris errors, the 3D accuracy of the POD is about30 cm. As for the precise relative orbit determination（PROD）, the 3D accuracy is much better over the eastern hemisphere than that of the western hemisphere. The baseline length accuracy is 3.4 mm over the service area, and it is still better than 1 cm over the non-service area. This paper demonstrates that the BeiDou regional constellation could provide global service to LEO satellites for the POD and the PROD. Finally, the benefit of geostationary earth orbit（GEO） satellites is illustrated for POD.展开更多
文摘LM launch vehicles established a new record by successfully performing the 16th successful flight this year.A LM-3A launched the 10th BeiDou 2 satellite into its predetermined transfer orbit on December 2 from the XSLC in Sichuan Province.
文摘为确保船舶航行安全,利用北斗二代卫星导航技术,设计船载定位终端.该终端以S3C2440ARM处理器和Windows CE 6.0嵌入式系统为核心,以外围电路为辅,采用最小二乘算法,实现船舶的导航定位.通过MATLAB软件对可见卫星数目和水平精度因子进行计算和分析,论证方案的可行性和可靠性,进一步推动北斗船载终端在航行中的应用.
文摘The BeiDou-2 satellite navigation system broadcasts triple frequency data. In this paper, the pseudorange multipath is extracted by using the geometry-free and ionosphere-free combination of one pseudorange and two phase measurements, and the phase multipath is extracted by using triple frequency phase measurements, respectively. By using several days’ static observation data, we exact the noisy pseudorange and phase multipath of three types of satellites, GEO, IGSO and MEO satellites. Because of the low frequency characteristics of the multipath, the low frequency wavelet filter is further used to recover the high-precision low frequency multipath signals that are specified by their amplitudes, periods and phases. The results show that the multipath periods are about 86160s, 86158s and 46391s for GEO, IGSO and MEO satellites, respectively, which coincide with that of the corresponding satellite orbits. Then we use the extracted multipath signals to correct the pseudorange measurements in order to improve the accuracy of point positioning. The positioning accuracy in East-West direction can be significantly improved by using the multipath corrected pseudorange measurements, and in the other two directions the positioning accuracy can also be improved to some extent.
基金co-supported by the National Natural Science Foundation of China (Nos: 61002033, 61370013)the Program for New Century Excellent Talents in University and the Scientific Research Foundation for the Returned Overseas Chinese Scholars of Ministry of Education of China
文摘The visibility for low earth orbit（LEO） satellites provided by the BeiDou-2 system is analyzed and compared with the global positioning system（GPS）. In addition, the spaceborne receivers＇ observations are simulated by the BeiDou satellites broadcast ephemeris and LEO satellites orbits. The precise orbit determination（POD） results show that the along-track component accuracy is much better over the service area than the non-service area, while the accuracy of the other two directions keeps at the same level over different areas. However, the 3-dimensional（3D） accuracy over the two areas shows almost no difference. Only taking into consideration the observation noise and navigation satellite ephemeris errors, the 3D accuracy of the POD is about30 cm. As for the precise relative orbit determination（PROD）, the 3D accuracy is much better over the eastern hemisphere than that of the western hemisphere. The baseline length accuracy is 3.4 mm over the service area, and it is still better than 1 cm over the non-service area. This paper demonstrates that the BeiDou regional constellation could provide global service to LEO satellites for the POD and the PROD. Finally, the benefit of geostationary earth orbit（GEO） satellites is illustrated for POD.
