多年冻土区地表高程因活动层每年的融化和冻结而发生季节性下沉和隆起，对工程建筑的安全、生态环境的平衡以及全球气候变化等方面都具有重要的影响。利用全球导航卫星系统干涉反射（global navigation satellite systeminterferometricreflectometry,GNSS-IR）遥感对冻土冻融形变进行监测是一种新型技术手段。针对格洛纳斯（GLONASS）、伽利略（Galileo）系统等长重访周期卫星因每日轨迹不重复造成的地形影响，提出了一种考虑地形的冻土冻融形变监测方法，通过引入反射面倾斜角消除地形变化影响，反演得到更接近实际情况的季节性冻融形变。利用位于美国阿拉斯加北部的SG27站点2018年、2019年无雪日GNSS信噪比数据进行了实验，并与现有研究中的反演方法所得结果进行了对比分析，验证了该方法在冻土冻融形变监测中的有效性。实验结果表明，相比于不考虑地形影响的方法，GLONASS和Galileo所得地表高程变化具有更小的离散性以及更小的不确定性，与复合模型拟合的一致性和决定系数R2都有了一定提升，标准差总平均分别减小约28.9%和36.9%,R2总平...

Ground subsidence and uplift caused by the annual thawing and freezing of the active layer are important variables in permafrost studies. Global positioning system interferometric reflectometry (GPS-IR) has been successfully applied to retrieve the continuous ground surface movements in permafrost areas. However, only GPS signals were used in previous studies. In this study, using multiple global navigation satellite system (GNSS) signal-to-noise ratio (SNR) observations recorded by a GNSS station SG27 in Utqiagvik, Alaska during the period from 2018 to 2021, we applied multiple GNSS-IR (multi-GNSS-IR) technique to the SNR data and obtained the complete and continuous ground surface elevation changes over the permafrost area at a daily interval in snow-free seasons in 2018 and 2019. The GLONASS-IR and Galileo-IR measurements agreed with the GPS-IR measurements at L1 frequency, which are the most consistent measurements among all multi-GNSS measurements, in terms of the overall subsidence trend but clearly showed periodic noises. We proposed a method to reconstruct the GLONASS- and Galileo-IR elevation changes by specifically grouping and fitting them with a composite model. Compared with GPS L1 results, the unbiased root mean square error (RMSE) of the reconstructed Galileo measurements reduced by 50.0% and 42.2% in 2018 and 2019, respectively, while the unbiased RMSE of the reconstructed GLONASS measurements decreased by 41.8% and 25.8% in 2018 and 2019, respectively. Fitting the composite model to the combined multi-GNSS-IR, we obtained seasonal displacements of - 3.27 +/- 0.13 cm (R-2 = 0.763) and - 10.56 +/- 0.10 cm (R-2 = 0.912) in 2018 and 2019, respectively. Moreover, we found that the abnormal summer heave was strongly correlated with rain events, implying hydrological effects on the ground surface elevation changes. Our study shows the feasibility of multi-GNSS-IR in permafrost areas for the first time. Multi-GNSS-IR opens up a great opportunity for us to investigate ground surface movements over permafrost areas with multi-source observations, which are important for our robust analysis and quantitative understanding of frozen ground dynamics under climate change.