利用EGM2008模型与地形改正进行GPS高程拟合

在工程测量中,全球定位系统GPS高程测量以其效率高、灵活性强等优势在困难环境下发挥了重要作用。实际应用中需要把GPS大地高转换为正常高,其关键在于精确求解高程异常。提出了一种基于EGM2008(Earth Gravitational Model)模型和地形变化的影响,并结合二次曲面函数来进行GPS高程拟合的方法。通过某跨海大桥工程的实测数据验证了该方法的GPS高程拟合精度,结果表明,该方法的内符合精度达到0.16 cm,外符合精度达到0.96 cm,能够提高GPS高程拟合的精度。

A GPS Height Fitting Method Based on the EGM2008 Model and Terrain Correction

GPS-derived height, due to the high efficiency and flexibility of GPS in engineering surveying, has been playing an important role under difficult environmental conditions. For applications in real projects, the geodetic height obtained by GPS should be transformed to normal height. The key issue in this transformation is to solve the height anomaly. This paper proposes a method to fit the residual height anomaly based on the EGM2008 model in combination with a separate terrain correction procedure. Datasets from an over-sea-bridge project were used to verify the performance of the proposed method. Numerical results show that, the proposed method can provide 0.16 cm accuracy for the points used for the fitting model determination and 0.96 cm accuracy for independent test points, and it can improve the precision of GPS height fitting.