Reducing the draconitic errors in GNSS geodetic products
Reducing the draconitic errors in GNSS geodetic products
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DOI：
10.1007/s00190-014-0704-1
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发表时间：
2014-06-01
影响因子：
4.4
通讯作者：
Fritsche, M.
中科院分区：
文献类型：
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作者：
Rodriguez-Solano, C. J.;Hugentobler, U.;Fritsche, M.
GPS龙年谐波的系统误差已被发现在不同的GPS派生大地测量产品，如地心分量，站坐标，极率和轨道（即轨道重叠）。GPS龙年是GPS星座w.r.t.太阳大约有351天。已经提出了不同的误差源，这些误差源可以在长谐波处产生这些寄生信号。在这项研究中，我们专注于这些误差来源之一，即辐射压力轨道建模的不足之处。为此，计算了8年（2004-2011年）的三个GPS+GLONASS解，它们仅在太阳辐射压（SRP）和卫星姿态模型方面有所不同。解决方案中采用的模型是：（1）在国际全球导航卫星系统服务界广泛使用的CODE（5参数）辐射压力模型，（2）SRP影响GPS（和GLONASS）卫星的可调箱形翼模型，以及（3）升级为使用非标称偏航姿态的可调箱形翼模型，特别是用于日食季节的卫星。在比较第一种解决方案与第三种解决方案时，我们在GNSS大地测量产品中实现了以下内容。轨道：对于GPS卫星，在所有谐波中，轨道重叠中的长周期误差对于径向、沿轨道和跨轨道分量平均减小46%、38%和57%，而对于GLONASS卫星，它们主要在跨轨道分量中减小39%。地心-组件：当使用CODE模型时发现的所有奇次龙子谐波都显示出新的辐射压力模型的非常重要的减少（几乎消失，平均减少92%）。地球定向参数：多极化率和特别是多极化率的地球定向误差分别减小了24%和50%。车站坐标：在北、东和高度分量中，所有的龙子谐波（除了北分量中的第二谐波）都减少，平均减少分别为41%、39%和35%。这表明，目前GNSS大地测量产品中发现的部分长轴误差肯定是由CODE辐射压力轨道模型的缺陷引起的。
Systematic errors at harmonics of the GPS draconitic year have been found in diverse GPS-derived geodetic products like the geocenter -component, station coordinates, -pole rate and orbits (i.e. orbit overlaps). The GPS draconitic year is the repeat period of the GPS constellation w.r.t. the Sun which is about 351 days. Different error sources have been proposed which could generate these spurious signals at the draconitic harmonics. In this study, we focus on one of these error sources, namely the radiation pressure orbit modeling deficiencies. For this purpose, three GPS+GLONASS solutions of 8 years (2004-2011) were computed which differ only in the solar radiation pressure (SRP) and satellite attitude models. The models employed in the solutions are: (1) the CODE (5-parameter) radiation pressure model widely used within the International GNSS Service community, (2) the adjustable box-wing model for SRP impacting GPS (and GLONASS) satellites, and (3) the adjustable box-wing model upgraded to use non-nominal yaw attitude, specially for satellites in eclipse seasons. When comparing the first solution with the third one we achieved the following in the GNSS geodetic products. Orbits: the draconitic errors in the orbit overlaps are reduced for the GPS satellites in all the harmonics on average 46, 38 and 57 % for the radial, along-track and cross-track components, while for GLONASS satellites they are mainly reduced in the cross-track component by 39 %. Geocenter -component: all the odd draconitic harmonics found when the CODE model is used show a very important reduction (almost disappearing with a 92 % average reduction) with the new radiation pressure models. Earth orientation parameters: the draconitic errors are reduced for the -pole rate and especially for the -pole rate by 24 and 50 % respectively. Station coordinates: all the draconitic harmonics (except the 2nd harmonic in the North component) are reduced in the North, East and Height components, with average reductions of 41, 39 and 35 % respectively. This shows, that part of the draconitic errors currently found in GNSS geodetic products are definitely induced by the CODE radiation pressure orbit modeling deficiencies.