为了对即将发布的新一代全球重力场模型EGM2020(Earth Gravitational Model 2020)在似大地水准面精化上的提升进行评估,通过其试验版的全球重力场模型XGM2019(X Gravitational Model 2019)利用扰动位配合布隆斯公式计算出高程异常的长波...为了对即将发布的新一代全球重力场模型EGM2020(Earth Gravitational Model 2020)在似大地水准面精化上的提升进行评估,通过其试验版的全球重力场模型XGM2019(X Gravitational Model 2019)利用扰动位配合布隆斯公式计算出高程异常的长波项,以评估XGM2019(Earth Gravitational Model 2008)相较于EGM2008(Earth Gravitational Model 2008)在直接转换为正常高精度上的提升;利用"移去-恢复-拟合"法以及顾及由地形起伏变化引起高程异常的短波波分,通过内符合精度和外符合精度来对比其在似大地水准面精度上的提升。以河南省平顶山市某区域的实测数据为例验证了该模型和方法的GPS高程拟合精度。结果表明,在研究区域内使用XGM2019模型在计算高程异常长波精度上相比EGM2008有近1倍的提高,在应用"移去-拟合-恢复"法后两种模型的计算结果比较相近。展开更多
The availability of many high-degree Global Geopotential Models(GGMs), namely EGM2008, EIGEN-6C4,GECO, SGG-UGM-1, SGG-UGM-2, XGM2019e_2159, and GGMPlus, challenges users regarding which model is best for Vietnam. This...The availability of many high-degree Global Geopotential Models(GGMs), namely EGM2008, EIGEN-6C4,GECO, SGG-UGM-1, SGG-UGM-2, XGM2019e_2159, and GGMPlus, challenges users regarding which model is best for Vietnam. This study, therefore, evaluates their performance by comparing them with GNSS/leveling data over Vietnam. Results show that their absolute and relative performances are largely independent of topographic conditions and geographical location and can be ranked into three classes:(1)XGM2019e_2159 has the highest accuracy,(2) the models EIGEN-6C4, GECO, SGG-UGM-1, SGG-UGM-2, and GGMPlus, have a very similar level of medium accuracy, while(3) EGM2008 is found to be the least accurate. In an absolute sense, the differences between GNSS/leveling and EGM2008-based height anomalies have a standard deviation(STD) of 0.290 ± 0.010 m, whereas, for XGM2019e_2159, this is 0.156 ± 0.006 m.All other models have STDs of(0.18-0.19) ± 0.007 m. Regarding relative performance without fitting, all GGMs have comparable accuracies for baseline length of 5-20 km, while for baselines longer than 20 km,the STD of XGM2019e_2159 is 1.5 ppm-0.5 ppm(approximately 19%-40%) lower compared with EGM2008, and 0.5 ppm-0.25 ppm(approximately 7%-36%) lower compared with EIGEN6C4, GECO,SGG-UGM-1, SGG-UGM-2, and GGMPlus. In addition, the STDs decrease significantly from 20 to 12 ppm in the range of 5-10 km, slightly from 12 to 6 ppm for 10-35 km, very slightly from 6 to 2.5 ppm for35-200 km, and then remain almost unchanged for longer baselines. After fitting, the relative accuracies of all GGMs are at the same level with negligible STD/RMSE values. Furthermore, only EGM2008 experiences significant regional differences, while other GGMs show more homogeneous spatial variation of absolute accuracy over Vietnam. These findings can contribute to the development of local quasigeoid models in Vietnam and may be helpful with the improvement of GGMs in the future.展开更多
文摘为了对即将发布的新一代全球重力场模型EGM2020(Earth Gravitational Model 2020)在似大地水准面精化上的提升进行评估,通过其试验版的全球重力场模型XGM2019(X Gravitational Model 2019)利用扰动位配合布隆斯公式计算出高程异常的长波项,以评估XGM2019(Earth Gravitational Model 2008)相较于EGM2008(Earth Gravitational Model 2008)在直接转换为正常高精度上的提升;利用"移去-恢复-拟合"法以及顾及由地形起伏变化引起高程异常的短波波分,通过内符合精度和外符合精度来对比其在似大地水准面精度上的提升。以河南省平顶山市某区域的实测数据为例验证了该模型和方法的GPS高程拟合精度。结果表明,在研究区域内使用XGM2019模型在计算高程异常长波精度上相比EGM2008有近1倍的提高,在应用"移去-拟合-恢复"法后两种模型的计算结果比较相近。
文摘The availability of many high-degree Global Geopotential Models(GGMs), namely EGM2008, EIGEN-6C4,GECO, SGG-UGM-1, SGG-UGM-2, XGM2019e_2159, and GGMPlus, challenges users regarding which model is best for Vietnam. This study, therefore, evaluates their performance by comparing them with GNSS/leveling data over Vietnam. Results show that their absolute and relative performances are largely independent of topographic conditions and geographical location and can be ranked into three classes:(1)XGM2019e_2159 has the highest accuracy,(2) the models EIGEN-6C4, GECO, SGG-UGM-1, SGG-UGM-2, and GGMPlus, have a very similar level of medium accuracy, while(3) EGM2008 is found to be the least accurate. In an absolute sense, the differences between GNSS/leveling and EGM2008-based height anomalies have a standard deviation(STD) of 0.290 ± 0.010 m, whereas, for XGM2019e_2159, this is 0.156 ± 0.006 m.All other models have STDs of(0.18-0.19) ± 0.007 m. Regarding relative performance without fitting, all GGMs have comparable accuracies for baseline length of 5-20 km, while for baselines longer than 20 km,the STD of XGM2019e_2159 is 1.5 ppm-0.5 ppm(approximately 19%-40%) lower compared with EGM2008, and 0.5 ppm-0.25 ppm(approximately 7%-36%) lower compared with EIGEN6C4, GECO,SGG-UGM-1, SGG-UGM-2, and GGMPlus. In addition, the STDs decrease significantly from 20 to 12 ppm in the range of 5-10 km, slightly from 12 to 6 ppm for 10-35 km, very slightly from 6 to 2.5 ppm for35-200 km, and then remain almost unchanged for longer baselines. After fitting, the relative accuracies of all GGMs are at the same level with negligible STD/RMSE values. Furthermore, only EGM2008 experiences significant regional differences, while other GGMs show more homogeneous spatial variation of absolute accuracy over Vietnam. These findings can contribute to the development of local quasigeoid models in Vietnam and may be helpful with the improvement of GGMs in the future.
