QZSS broadcast ephemeris accuracy evaluation and fitting accuracy analysis
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摘要: 实时导航定位中需要利用广播星历实时计算卫星位置,日本建设的准天顶卫星系统(QZSS)计算卫星位置时通过不断迭代提高计算精度,导致实时解算效率降低. 为了保证QZSS广播星历坐标计算精度且提高运算效率,提出利用切比雪夫多项式拟合卫星轨道. 首先,使用原有方法计算卫星位置,以精密星历为参考,验证QZSS广播星历的卫星坐标精度为米级;然后,针对卫星三维(3D)坐标使用切比雪夫多项式进行拟合,并讨论影响拟合精度的因素,在拟合时间间隔固定时,最优拟合阶数随节点个数增多而增大;不同时间间隔下,不同轨道类型的最优拟合阶数不相等,同一轨道最优拟合阶数相等,但随时间间隔的增大拟合误差也逐渐增大. 结果表明:使用切比雪夫多项式拟合QZSS广播星历时,针对不同的轨道类型选择合适的拟合时间间隔和拟合阶数,其拟合精度和运算效率均可满足需要.
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关键词:
- 准天顶卫星系统(QZSS) /
- 广播星历 /
- 切比雪夫多项式 /
- 拟合精度
Abstract: Broadcast ephemeris is needed to calculate the satellite position in real-time navigation and positioning. The continuous iteration is used to improve the calculation accuracy in the quasi-zenitic satellite system (QZSS) built by Japan during calculating the satellite position, which can result in the real-time calculation efficiency reduction. In order to ensure the calculation accuracy and improve the calculation efficiency of QZSS broadcast ephemeris coordinates, a chebyshev polynomial is proposed to fit the satellite orbit. Firstly, the traditional methods are used to calculate satellite position, the precision ephemeris is regarded as a reference to verify that the satellite coordinate accuracy of QZSS broadcast ephemeris is meter-level. And then, a chebyshev polynomial is used to fit satellite three-dimension coordinates, and the factors affecting the fitting accuracy are discussed. When the fitting time-interval is fixed, the optimal fitting order increases with the number of nodes; Under different time-intervals, the optimal fitting order is not equal in different orbit types, and the optimal fitting order of the same orbit is equal, but the fitting error gradually increases with the increase of time-interval. The result shows that QZSS broadcast ephemeris can be fitted by using a chebyshev polynomial and choosing appropriate fitting time-interval and fitting order for different orbit types. The fitting accuracy and computational efficiency can meet the needs. -
表 1 空间大地坐标系误差统计
m 卫星编号 轨道类型 Max Mean Std X Y Z X Y Z X Y Z J01 IGSO 3.810 3.595 2.883 2.332 2.000 1.576 0.420 0.681 1.729 J02 IGSO 2.922 2.486 1.629 0.719 0.626 0.380 0.449 0.677 0.433 J03 IGSO 2.674 6.164 1.463 1.001 0.899 0.609 0.807 1.098 0.676 J07 GEO 3.231 4.472 0.593 2.284 2.492 0.176 0.493 0.524 0.217 表 2 卫星轨道坐标系误差统计
m 卫星编号 轨道类型 Max Mean Std R T N R T N R T N J01 IGSO 1.544 1.024 4.541 0.497 0.272 3.536 0.472 0.272 0.347 J02 IGSO 2.058 2.388 3.091 0.234 0.399 0.918 0.336 0.520 0.592 J03 IGSO 4.647 5.315 3.309 0.369 0.648 1.238 0.595 1.156 0.450 J07 GEO 3.484 1.804 4.392 0.924 0.559 3.110 1.203 0.682 0.638 表 3 X方向上节点个数与拟合阶数不同组合的拟合误差
mm 拟合阶数 节点个数 7 10 13 16 Max Mean Std Max Mean Std Max Mean Std Max Mean Std 6 899.80 145.100 149.800 8102.000 1612.000 1417.000 41417.000 8704.000 7484.000 148251.000 32118.000 27246.000 7 12.48 1.217 1.887 138.700 18.770 20.290 885.800 139.400 137.400 3890.000 651.300 625.200 8 2.701 0.211 0.315 19.350 2.020 2.528 102.000 12.030 14.070 9 0.421 0.034 0.038 0.566 0.046 0.053 2.682 0.224 0.323 10 1.412 0.076 0.115 0.402 0.029 0.031 0.257 0.027 0.027 11 0.454 0.036 0.043 0.358 0.028 0.029 12 1.609 0.055 0.099 0.484 0.030 0.034 13 23.890 0.771 2.090 0.924 0.043 0.064 14 2.287 0.082 0.185 15 38.950 0.755 2.423 16 464.800 10.310 35.490 表 4 Y方向上节点个数与拟合阶数不同组合的拟合误差
mm 拟合阶数 节点个数 7 10 13 16 Max Mean Std Max Mean Std Max Mean Std Max Mean Std 6 898.20 145.40 150.900 8092.000 1620.000 1426.000 41347.000 8765.000 7516.000 147966.000 32417.00 27293.000 7 12.64 1.22 1.893 140.500 18.810 20.370 896.800 139.600 138.000 3935.000 651.20 628.500 8 2.682 0.212 0.316 19.310 2.022 2.541 101.700 12.01 14.180 9 0.492 0.037 0.042 0.529 0.048 0.054 2.760 0.227 0.325 10 1.241 0.077 0.116 0.354 0.031 0.033 0.272 0.030 0.030 11 0.644 0.038 0.046 0.305 0.030 0.032 12 1.807 0.057 0.100 0.507 0.032 0.036 13 23.280 0.794 2.137 1.095 0.044 0.064 14 2.518 0.081 0.182 15 27.530 0.685 2.096 16 434.700 8.752 29.63 表 5 Z方向上节点个数与拟合阶数不同组合的拟合误差
mm 拟合阶数 节点个数 7 10 13 16 Max Mean Std Max Mean Std Max Mean Std Max Mean Std 6 272.400 28.680 39.680 2452.000 319.400 389.800 12537.000 1721.000 2075.000 44904.000 6328.000 7602.000 7 3.140 0.256 0.486 34.620 3.933 5.498 221.200 29.170 37.900 970.300 136.200 173.600 8 0.793 0.052 0.089 5.849 0.493 0.733 30.840 2.937 4.112 9 0.138 0.010 0.012 0.145 0.013 0.015 0.790 0.065 0.101 10 0.756 0.043 0.073 0.084 0.007 0.007 0.058 0.006 0.006 11 0.264 0.012 0.018 0.069 0.007 0.006 12 0.615 0.026 0.052 0.115 0.008 0.009 13 24.450 0.547 1.694 0.473 0.017 0.034 14 1.777 0.049 0.128 15 25.210 0.496 1.726 16 399.600 8.281 27.580 表 6 X方向上节点个数与拟合阶数不同组合的拟合误差
mm 拟合阶数 节点个数 7 10 13 16 Max Mean Std Max Mean Std Max Mean Std Max Mean Std 5 15.190 2.717 2.589 100.100 19.250 17.790 391.100 76.920 70.060 1128.000 225.700 204.400 6 0.335 0.044 0.043 1.419 0.246 0.227 7.231 1.309 1.201 26.350 4.837 4.389 7 0.391 0.042 0.046 0.291 0.035 0.036 0.298 0.040 0.036 0.544 0.098 0.084 8 0.339 0.036 0.039 0.268 0.034 0.035 0.242 0.033 0.033 9 0.570 0.042 0.049 0.328 0.035 0.037 0.246 0.034 0.034 10 1.576 0.082 0.121 0.451 0.037 0.040 0.279 0.034 0.035 11 0.816 0.045 0.056 0.436 0.036 0.038 12 1.442 0.068 0.115 0.540 0.039 0.044 13 28.680 0.767 2.159 1.024 0.051 0.073 14 2.522 0.088 0.186 15 33.070 0.723 2.216 16 410.600 9.286 30.570 表 7 Y方向上节点个数与拟合阶数不同组合的拟合误差
mm 拟合阶数 节点个数 7 10 13 16 Max Mean Std Max Mean Std Max Mean Std Max Mean Std 5 13.280 2.441 2.341 88.510 17.330 16.160 348.700 69.370 63.980 1014.000 204.000 187.500 6 0.268 0.037 0.034 1.252 0.226 0.207 6.288 1.199 1.094 21.870 4.407 3.989 7 0.276 0.032 0.035 0.231 0.027 0.028 0.231 0.033 0.029 0.529 0.088 0.077 8 0.238 0.029 0.030 0.194 0.027 0.027 0.194 0.026 0.026 9 0.462 0.035 0.038 0.253 0.028 0.028 0.201 0.026 0.026 10 1.267 0.090 0.134 0.305 0.029 0.031 0.224 0.027 0.027 11 0.589 0.038 0.045 0.373 0.028 0.029 12 1.311 0.059 0.100 0.440 0.031 0.034 13 28.960 0.965 2.570 1.237 0.052 0.083 14 2.436 0.090 0.200 15 46.310 1.164 3.604 16 462.500 10.910 37.540 表 8 Z方向上节点个数与拟合阶数不同组合的拟合误差
mm 拟合阶数 节点个数 7 10 13 16 Max Mean Std Max Mean Std Max Mean Std Max Mean Std 5 18.430 4.843 3.817 117.900 33.940 25.630 446.500 133.940 99.540 1246.000 388.300 287.700 6 0.235 0.037 0.039 2.133 0.420 0.369 10.990 2.282 1.956 39.470 8.432 7.132 7 0.002 0.000 0.000 0.016 0.003 0.002 0.091 0.018 0.015 0.363 0.081 0.067 8 0.001 0.000 0.000 0.005 0.001 0.001 0.027 0.004 0.004 9 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 10 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 11 0.000 0.000 0.000 0.000 0.000 0.000 12 0.001 0.000 0.000 0.000 0.000 0.000 13 0.043 0.001 0.003 0.001 0.000 0.000 14 0.003 0.000 0.000 15 0.042 0.001 0.003 16 0.528 0.013 0.041 表 9 J01卫星不同时间间隔下最优组合的误差统计
时间间隔/s 节点个数 拟合阶数 X/mm Y/mm Z/mm Max Mean Std Max Mean Std Max Mean Std 120 31 10 0.208 0.025 0.023 0.246 0.027 0.026 0.052 0.007 0.006 180 21 10 0.209 0.026 0.025 0.238 0.028 0.028 0.053 0.006 0.005 240 16 10 0.257 0.027 0.027 0.272 0.030 0.030 0.058 0.006 0.006 300 13 10 0.358 0.030 0.032 0.346 0.033 0.035 0.078 0.008 0.007 360 11 10 0.696 0.037 0.044 0.756 0.040 0.050 0.130 0.010 0.013 表 10 J07卫星不同时间间隔下最优组合的误差统计
时间间隔/s 节点个数 拟合阶数 X/mm Y/mm Z/mm Max Mean Std Max Mean Std Max Mean Std 120 31 7 0.481 0.091 0.076 0.432 0.082 0.070 0.307 0.075 0.060 180 21 7 0.518 0.095 0.080 0.479 0.085 0.074 0.335 0.078 0.064 240 16 7 0.544 0.098 0.084 0.529 0.088 0.077 0.363 0.081 0.067 300 13 7 0.615 0.100 0.088 0.566 0.090 0.081 0.395 0.083 0.070 360 11 7 0.663 0.102 0.093 0.611 0.091 0.085 0.434 0.084 0.075 -
[1] 夏岩, 王庆华, 宋铮, 等. 日本QZSS卫星导航系统[J]. 卫星应用, 2015(4): 40-43. [2] 江永生. QZSS增强信号对GPS定位增强效果的分析[J]. 北京测绘, 2019, 33(8): 969-973. [3] 布金伟, 左小清, 金立新, 等. BDS/QZSS及其组合系统在中国和日本及周边地区的定位性能评估[J]. 武汉大学学报(信息科学版), 2020, 45(4): 574-585, 611. [4] 楼益栋, 郑福, 龚晓鹏, 等. QZSS系统在中国区域增强服务性能评估与分析[J]. 武汉大学学报(信息科学版), 2016, 41(3): 298-303. [5] 李振昌, 李仲勤, 寇瑞雄. 非滑动式与滑动式拉格朗日插值法在BDS精密星历内插中的比较分析[J]. 天文研究与技术, 2019, 16(1): 54-60. [6] 孙华丽, 张政治, 胡思才. 五次样条插值在GPS卫星轨道标准化中的应用[J]. 大地测量与地球动力学, 2012, 32(1): 76-79. [7] 仝海波, 沙海, 张国柱, 等. 一种GNSS卫星轨道高精度实时插值方法[J]. 国防科技大学学报, 2012, 34(2): 59-63. DOI: 10.3969/j.issn.1001-2486.2012.02.015 [8] Quasi-Zenith Satellite System. Satellite positioning, navigation and timing service(IS-QZSS-PNT-003) [S/OL]. (2018-11-05) [2020-10-03]. https://qzss.go.jp/en/overview/services/svo4_pnt.html [9] 贡冀鑫. QZSS卫星导航系统性能分析[D]. 西安: 长安大学, 2019. [10] 刘磊, 盛峥, 王迎强, 等. 利用广播星历计算GPS卫星位置及误差分析[J]. 解放军理工大学学报(自然科学版), 2006, 7(6): 592-596.