GNSS related periodic signals in coordinate time-series from Precise Point Positioning
GNSS related periodic signals in coordinate time-series from Precise Point Positioning
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DOI：
10.1093/gji/ggw467
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发表时间：
2017-03-01
影响因子：
2.8
通讯作者：
Dach, R.
中科院分区：
文献类型：
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作者：
Abraha, K. E.;Teferle, F. N.;Dach, R.
在全球卫星导航系统（GNSS）中，坐标时间序列的不可识别误差和未建模（周期）效应可能会对地球物理信号引起的非线性运动产生偏差。因此，理解和减轻这些错误对于减少偏差和揭示微妙的地球物理信号至关重要。为了评估坐标时间序列中周期信号的性质，生成了2008-2015年期间的精确点定位（PPP）解决方案。这些解决方案考虑全球定位系统（GPS）、全球导航系统（GLONASS）或GPS+GLONASS （GNSS）联合观测。我们评估了使用国际GNSS服务（IGS）及其四个分析中心（ACs）产品计算的站点坐标的周期信号。此外，我们利用不同的滤波方法来研究周期信号的来源。在我们基于喷气推进实验室（JPL）产品的PPP解决方案中，每两周有一个微弱的信号，而那些产生GPS+GLONASS组合产品的ac存在8天周期，这是仅GPS解决方案的主要特点。仅GPS解决方案中8 d周期的存在表明，在组合GNSS解决方案中计算的GPS轨道包含glonass特定信号。GLONASS-only解除了众所周知的年、半年和其他次次谐波外，在第三次次谐波（类似于120 d周期）、8 d周期及其次谐波（4 d, 2.67 d）上的幂次都有很高的提高。我们证明了2011年12月之前的GLONASS星座间隙对某些频率的功率有贡献。然而，仅gps解决方案中众所周知的每两周一次的信号在仅glonass解决方案中是无法识别的。联合GNSS解决方案包含来自两个系统的周期性信号，与单一GNSS解决方案相比，大部分功率都降低了。与仅使用gps的解决方案相比，GNSS解决方案每两周发出的信号水平分量减少52%，垂直分量减少36%。比较所采用的滤波方法的结果表明，绝大多数周期信号和双周信号的功率源是卫星诱导的，其站点特定误差的贡献不为零。
In Global Navigation Satellite System (GNSS) coordinate time-series unrecognized errors and unmodelled (periodic) effects may bias nonlinear motions induced by geophysical signals. Hence, understanding and mitigating these errors is vital to reducing biases and on revealing subtle geophysical signals. To assess the nature of periodic signals in coordinate time-series Precise Point Positioning (PPP) solutions for the period 2008-2015 are generated. The solutions consider Global Positioning System (GPS), GLObalnaya NAvigatsionnaya Sputnikovaya Sistema (GLONASS) or combined GPS+GLONASS (GNSS) observations. We assess the periodic signals of station coordinates computed using the combined International GNSS Service (IGS) and four of its Analysis Centers (ACs) products. Furthermore, we make use of different filtering methods to investigate the sources of the periodic signals. A faint fortnightly signal in our PPP solution based on Jet Propulsion Laboratory (JPL) products and the existence of an 8 d period for those ACs generating combined GPS+GLONASS products are the main features in the GPS-only solutions. The existence of the 8 d period in the GPS-only solution indicates that GPS orbits computed in a combined GNSS solution contain GLONASS-specific signals. The GLONASS-only solution shows highly elevated powers at the third draconitic harmonic (similar to 120 d period), at the 8 d period and its harmonics (4 d, 2.67 d) besides the well-known annual, semi-annual and other draconitic harmonics. We show that the GLONASS constellation gaps before December 2011 contribute to the power at some of the frequencies. However, the well-known fortnightly signal in GPS-only solutions is not discernible in the GLONASS-only solution. The combined GNSS solution contains periodic signals from both systems, with most of the powers being reduced when compared to the single-GNSS solutions. A 52 per cent reduction for the horizontal components and a 36 per cent reduction for the vertical component are achieved for the fortnightly signal from the GNSS solution compared to the GPS-only solution. Comparing the results of the employed filtering methods reveals that the source of most of the powers of draconitic and fortnightly signals are satellite-induced with a non-zero contribution of site-specific errors.