考虑潮波特性的GNSS-IR潮位反演方法

GNSS-IR retrieval method with consideration of tidal periodicity of sea level

潮位监测对于保障沿海安全、海洋监测与分析非常重要。随着GNSS的发展,一种GNSS干涉遥感(GNSS-IR)的技术被证明可以进行潮位监测。该方法通过反演反射表面与天线之间的垂直距离(RH)来估算潮位。在GNSS-IR潮位反演中,有一项重要的误差源需要进行改正——潮位起伏引起的高度变化误差。现有的误差改正方法并不能正确计算RH变化速率,从而不能完全改正该误差。因此,提出了一种顾及潮波特性的GNSS-IR融合方法,基于潮波系数,预测窗口内观测时间的RH变化速率,将该值纳入GNSS-IR融合方程中,实现对高度变化误差更好地改正。本文利用3个国际GNSS站点进行试验,与实测潮位序列对比分析,发现顾及潮波特性后,GNSS-IR融合方法精度提高约1.2 cm;提出的顾及潮波特性的GNSS-IR融合反演算法较传统经典方法,精度提升20%~70%。结果表明,该方法通过潮汐分析,预测不同时刻的RH变化速率,从而实现对窗口内RH变化速率的修正,更好地改正高度变化误差。

Sea level monitoring is important for coastal production and safety,marine monitoring and analysis.With the development of Global navigation satellite systems(GNSS),a new technology called GNSS-interferometry reflectometry(GNSS-IR)has been demonstrated can be used to monitor coastal sea level.The vertical distance between reflecting surface and antenna named reflector height(RH)can be estimated from the observations,and then the sea level can be retrieved.There is an important error named height variation error in this technique causing by the movement of sea surface.However,the classical correction method cannot calculate RH rate accurate and subsequently cannot effectively correct the error.So,this paper presented a GNSS-IR combination method with the consideration of tidal periodicity of sea level.Based on the tidal wave coefficient,the RH rate of change can be predicted and incorporated into the GNSS-IR combination equation to better correct the height variation error.The paper conducted experiments using three international GNSS stations.Compared with sea level measurements,the results showed that the accuracy of the GNSS-IR combined retrievals were improved by approximately 1.2 cm when tidal wave characteristics were considered than when were not,and they achieved an accuracy improvement of 20%to 70%compared to classical algorithms.The results indicate that the improved algorithm corrects height variation errors more effectively by predicting RH rate of change at different times through tidal analysis.