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.

中文翻译：

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结合 GPS 和 GLONASS 测量海洋潮汐载荷位移的好处

GPS 已被用于估计 M2 频率下的海洋潮汐载荷 (OTL) 高度位移幅度，精度在 0.5 毫米以内，但这种估计在月球-太阳 K2 和 K1 频率上存在问题，因为它们与 GPS 轨道周期重合周期，导致重复的多径和卫星轨道误差。因此，我们研究了使用 GLONASS 星座（轨道周期为 11.26 小时，与 K2 和 K1 不同的 8 个恒星日的真实站点重访周期）进行 OTL 位移估计的潜力，分析了来自全球分布的 49车站。在具有浮动模糊度的运动学精确点定位模式下使用 PANDA 软件，我们证明 GLONASS 可以估计 M2、N2、具有与 GPS 相似精度的 O1 和 Q1 月球频率：估计和 FES2014b 海洋潮汐模型位移之间的 95% 一致性为 0.6-1.3 毫米。在 K2 和 K1 月球-太阳频率下，GPS 估计值与模型值 3.9-4.4 毫米之间的第 95 个百分位数一致性提高到 2.0-2.8 毫米，仅使用 GLONASS 解决方案。与单星座解决方案相比，组合 GPS + GLONASS 浮动解决方案提高了月球 OTL 成分和 P1 的精度（但对 K1 或 K2 没有显着影响），并导致每小时到每周的频谱噪声与 GPS 模糊度固定非常相似解，但不需要未校准的相位延迟信息。由于卫星能见度提高，GLONASS 估计在高纬度比低纬度更准确，尽管这可以通过使用较低的仰角截止角来抵消。