联合中国近海海潮模型与全球海潮模型分析海潮负荷对GPS精密定位的影响
Effect Analysis of Ocean Tide Loading on GPS Precise Positioning Combining High Precision Local Tide Model with Global Ocean Tide Model
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摘要: 利用卫星测高技术建立的全球海潮模型的精度和分辨率均有限,而高精度、高分辨率的近海区域潮汐观测资料,可用于改善和提高全球海潮模型在沿海地区的精度。利用中国东海和南海的近海海潮模型,对HAMTIDE11A.2011全球海潮模型中的中国近海区域进行了替换,并得到了修正前后模型计算的海潮负荷对不同区域GPS测站精密定位的影响。分析可得:(1)确认修正前后的全球海潮模型计算的海潮负荷对GPS测站精密定位的影响存在约5 mm的差异,并通过频谱分析得到修正后的模型在GPS精密定位中剔除海潮负荷影响的效果在半日、周日及半年周期处明显优于修正前的模型;(2)采用高精度近海模型进一步修正全球海潮模型,该成果对近海区域的GPS精密定位海潮负荷改正具有一定参考价值。Abstract: The accuracy and resolution of global ocean tide models established by satellite altimetry technology are often limited.The data from local offshore tidal models generated by long-term observation of local tide stations however, is highly precise and at high resolution and could be used to improve the accuracy of global ocean tide models. In this paper, we use the high accuracy local tidal data from the East and South China Seas to refine the local area of the HAMTIDE11A.2011 global ocean tide model. We also analyze the effect of ocean tide loading observed by elaboration and non-elaboration models on the precise positioning of GPS stations distributed across different areas. The results show that 1) the effects of ocean tide loading calculated by the global ocean tide model elaboration and non-elaboration with precise positioning from GPS stations have a millimeter level difference, and 2) the deduction results for the ocean tide loading effect computed by elaboration model with GPS precise positioning is better than the non-elaboration model using the fast Fourier transform method for the semidiurnal, diurnal and semiannual periods.