从累积大地水准面误差、几何水准面与重力水准面之差、不同频段重力场模型的组合3个方面,评估了欧空局发布的时域法、空域法、直接法3个模型的精度。频谱分析和北美实测GPS/水准结果表明,第4代直接法模型精度达到"空间分辨率100km情况下,大地水准面精度±1cm"的设计要求;直接法模型精度高于时域法模型和空域法模型;GOCE数据能有效地提高重力场中频、甚至高频信号的精度。
Three kinds of GOCE-based gravity field models,i.e.time-wise models,space-wise models and direct approach models released by ESA,are evaluated from three schemes including accumulative geoid errors,geoid height differences and combination of the models in different spectral bands.Results from spectral analyses and GPS/leveling geoid difference in North America indicate that,the 4th generation model from direct approach satisfies the GOCE mission objective of achieving±1cm geoid accuracy at a spatial resolution of approximately 100km.The direct approach models have the better performance compared to time-wise models and space-wise models.GOCE data products can improve the accuracy of middle to high spectral band signals of gravity fields.