Benefits of combining GPS and GLONASS for measuring ocean tide loading displacement
Benefits of combining GPS and GLONASS for measuring ocean tide loading displacement
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DOI：
10.1007/s00190-020-01393-5
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发表时间：
2020-07
影响因子：
4.4
通讯作者：
Majid Abbaszadeh;P. Clarke;N. Penna
中科院分区：
文献类型：
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作者：
Majid Abbaszadeh;P. Clarke;N. Penna
GPS已被用来估计海潮负荷（OTL）的高度位移幅度的精度在0.5毫米内的M2频率，但这样的估计一直是有问题的，在日月K2和K1频率，因为它们与GPS轨道周期和重访周期，导致重复的多路径和卫星轨道误差。因此，我们调查的潜力，使用GLONASS星座（轨道周期11.26小时和真正的网站重访期8恒星日不同于K2和K1）OTL位移估计，分析3-7年的GPS和GLONASS数据从全球分布的49个站。在具有浮点模糊度的运动学精确单点定位模式下使用PANDA软件，我们证明GLONASS可以估计M2，N2，O 1和Q1月球频率下的OTL高度位移，其精度与GPS相似：估计值与FES 2014 b海潮模型位移之间的第95百分位数一致性为0.6-1.3 mm。在K2和K1日月频率上，全球定位系统估计值与模型值之间的第95百分位一致率从3.9-4.4毫米提高到2.0-2.8毫米，而使用仅使用全球轨道导航卫星系统的解决方案。与单一星座方案相比，GPS+GLONASS组合浮动方案提高了月球OTL成分和P1的精度（但对K1或K2没有显著影响），并产生了与GPS模糊度固定方案非常相似的每小时到每周的频谱噪声，但不需要未经校准的相位延迟信息。由于卫星能见度提高，全球轨道导航卫星系统的估计在高纬度地区比在低纬度地区更准确，不过这可以通过使用较低的仰角截止角来抵消。
GPS has been used to estimate ocean tide loading (OTL) height displacement amplitudes to accuracies of within 0.5 mm at the M2 frequency, but such estimation has been problematic at luni-solar K2 and K1 frequencies because they coincide with the GPS orbital period and revisit period, leading to repeating multipath and satellite orbit errors. We therefore investigate the potential of using the GLONASS constellation (with orbital period 11.26 h and true site revisit period of 8 sidereal days distinct from K2 and K1) for OTL displacement estimation, analysing 3–7 years of GPS and GLONASS data from 49 globally distributed stations. Using the PANDA software in kinematic precise point positioning mode with float ambiguities, we demonstrate that GLONASS can estimate OTL height displacement at the M2, N2, O1 and Q1 lunar frequencies with similar accuracy to GPS: 95th percentile agreements of 0.6–1.3 mm between estimated and FES2014b ocean tide model displacements. At the K2 and K1 luni-solar frequencies, 95th percentile agreements between GPS estimates and model values of 3.9–4.4 mm improved to 2.0–2.8 mm using GLONASS-only solutions. A combined GPS+GLONASS float solution improves accuracy of the lunar OTL constituents and P1 (but not significantly for K1 or K2) compared with a single-constellation solution and results in hourly-to-weekly spectral noise very similar to a GPS ambiguity-fixed solution, but without needing uncalibrated phase delay information. GLONASS estimates are more accurate at higher compared with lower latitudes because of improved satellite visibility, although this can be countered by using a lower elevation cut-off angle.