红河断裂剖面GNSS监测站数据质量评估分析

Quality evaluation and analysis on GNSS data in Red River fault profile surveying

从多路径效应、信噪比(SNR)、卫星天空图、精度衰减因子(DOP)等方面对红河断裂带剖面所建的16个GNSS监测站的观测数据进行了质量检查与评估分析。结果表明,测站B8数据质量最差,L2多路径效应达到了近1m,SNR为30.2,这与测站实际环境相吻合。除测站B8外,其它各站均优于全球IGS站数据质量状况。并对测站B8进一步分析了所有可视卫星SNR和DOP在一天中随时间的变化情况,发现在GPST时07:30,16:00,23:00左右出现了三次卫星数急剧下降、DOP值急剧增加的极不稳定的波动现象;对GNSS连续站自建站起至今共382d的观测数据进行了质量分析,发现L1/L2 SNR均有不同程度的衰减,平均衰减速度分别为0.73d B/年和2.19d B/年,随着时间的推移可能会影响到观测数据质量和地壳形变分析的结果,需及时跟踪监测仪器稳定性变化。这些分析为后续的GPS数据处理和地壳形变分析提供了依据。

From the multipath effect,the signal-to-noise ratio（ SNR）,satellite sky chart,and precision attenuation factor（ DOP）,a quality evaluation method of the GNSS observation data is discussed. Take 16 observation stations established in the profile of Red River fault zone as an example,the analysis result shows that the data quality of the station B8 is worst. Its L2 multipath effect is about 1m,SNR is about30. 2,which agree well with the actual surrounding environment. Besides the station B8,the data quality of other stations is better than IGS station. Further,the change of SNR and DOP of all visible satellite with time of 1 day are analyzed. It is found that at GPST 07： 30,16： 00,and about 23： 00 appeared three times volatile fluctuations,visible satellite number fell sharply,and DOP value increased dramatically. By analyzing GNSS continuous observation data of 382 days from establishment of stations to present,L1 / L2 SNR have the trend of attenuation in different degrees and the average attenuation speed are 0. 73 d B / year and 2. 19 d B / year respectively. With time increasing,data quality and crustal deformation analysis will be influenced,so the stability of the instrument needs real-time tracking and monitoring. The data quality analysis provides a basis for choice of data in subsequent data processing.