Analysis of signal strength, satellite visibility, position accuracy and ionospheric TEC estimation of IRNSS
Analysis of signal strength, satellite visibility, position accuracy and ionospheric TEC estimation of IRNSS
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DOI：
10.1007/s10509-019-3676-z
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发表时间：
2019-11
影响因子：
1.9
通讯作者：
R. Mukesh;V. Karthikeyan;P. Soma;P. Sindhu
中科院分区：
文献类型：
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作者：
R. Mukesh;V. Karthikeyan;P. Soma;P. Sindhu
印度区域导航卫星系统（IRNSS）是印度为满足实际需要而自行开发的卫星导航系统。该系统由GEO轨道上的七颗卫星组成，自2018年以来一直在全面运行。对于各种应用，必须持续评估IRNSS的性能。作为ISRO现场试验和数据收集计划的一部分，IRNSS标准定位服务用户接收器（UR）放置在班加罗尔的ACS工程学院（ACSCE），用于独立的现场试验和数据收集。接收机在基地上工作。开发了MATLAB图形用户界面，可以分析和绘制信号强度、仰角、卫星可见度、用户位置、位置误差、几何精度因子（GDOP）等数据的变化，并根据接收到的数据求出每秒绘制的卫星数的可用性。根据结果，观察到信号强度（C/No）良好，即高于40 dBHz，接收器位置处的卫星的可见性良好。在用户位置处的平均位置被发现是，并且纬度为12.8914度，经度为77.465度，海拔为739米。IRNSS的平均位置与Google地图结果进行比较，显示出良好的匹配。估计和观测了接收机位置相对于地球中心的几何距离。班加罗尔ACSCE的L1、L5和双频（L5+S）位置误差的RMS分别为9.7444 m、6.6873 m和5.6667 m。因此，正如预期的那样，双频（L5+S）接收机给出准确的位置，而不是单频信号。利用ACSCE接收机采集的L5和S波段的伪距和电离层群时延测量IRNSS TEC。三阶Savitzky-Golay滤波技术用于TEC平滑。IRNSS伪距TEC与GPS TEC的RMSE为0.6482 TECU，相关系数为0.9981。由L5/S电离层延迟得到的IRNSS TEC与GPS TEC之间的RMSE为1.971 TECU，相关系数为0.9966。最后，平滑TEC值来自伪距测量给出了一个很好的结果，可以用来生成每日TEC地图。为了分析IRNSS在印度地区的性能，我们选择了位于Osmania大学（海得拉巴），Burdwan大学（Bardhaman，西孟加拉）和Shri Mata Vaishno Devi大学（卡特拉，查谟和克什米尔）的其他三个接收站。基于结果，我们得出结论，IRNSS星座是执行良好，并提供了良好的信号，准确的用户位置确定和电离层数据分析。
The Indian Regional Navigation Satellite System (IRNSS) is an indigenously developed satellite navigation system to meet practical needs. The system, comprising a constellation of seven satellites in GEO orbit, has been fully operational since 2018. It is essential to evaluate the performance of the IRNSS continuously for various applications. As a part of ISRO field trial and data collection program an IRNSS Standard Positioning Service User Receiver (UR) placed at ACS College of Engineering (ACSCE), Bangalore, for independent field trial and data collection. The receiver is operational on abasis. A MATLAB Graphical User Interface has been developed to analyze and plot the data variation of signal strength, elevation angle, visibility of satellites, user position, position error, geometric dilution of precision (GDOP) and find the availability of the number of satellites plotted for every second based on the received data. From the results, it is observed that the signal strength (C/No) is good, i.e. above 40 dBHz, visibility of satellites at receiver location is good. The mean position at user location is found to be,,and latitude of 12.8914 degree, longitude of 77.465 degree and altitude of 739 m. The mean position from IRNSS is compared with Google map results showing a good match. The geometry distance of receiver location with respect to Earth center is estimated and observed. The RMS of position error for L1, L5 and dual frequency (L5+S) at ACSCE, Bangalore, is 9.7444 m, 6.6873 m and 5.6667 m, respectively. Hence, as expected the dual-frequency (L5+S) receiver gives an accurate position rather than the single-frequency signals. The IRNSS TEC is measured using Ionospheric group delay and the pseudo-range of L5 and S band which is collected from ACSCE receiver. A third order Savitzky-Golay-Filtered technique is used for TEC smoothing. RMSE between IRNSS TEC from pseudo-range and GPS TEC is 0.6482 TECU and the correlation coefficient is 0.9981. RMSE between IRNSS TEC from ionospheric delay of L5/S and GPS TEC is 1.971 TECU and the correlation coefficient is 0.9966. Finally, smoothed TEC values derived from pseudo-range measurements give a good result and can be used to generate daily TEC maps. In order to analyze the performance of IRNSS over the Indian region, we have chosen three other receiver stations located at Osmania University (Hyderabad), University of Burdwan (Bardhaman, West Bengal) and Shri Mata Vaishno Devi University (Katra, Jammu and Kashmir). Based on the results, we conclude that the IRNSS constellation is performing well and providing good signals for accurate user position determination and ionospheric data analysis.