08. ASSESSMENT OF THE ACCURACY OF THE GLOBAL GRAVITY FIELD MODEL GAO 2012 ON THE TERRITORY OF VIETNAM

Tóm tắt

The accuracy of GAO 2012 model on the Vietnamese territory is evaluated using 819 GNSS/levelling points of the national levelling networks by comparing the height anomaly of the point was calculated from the field measurement results with the height anomaly of that point was exploited from the GAO 2012 model and the difference in the height anomaly of pairs of points. The results show that the average height anomaly deviation compared to height anomalies exploited from GAO 2012 model is 0.3974 meters. The highest accuracy of GAO 2012 model is in Southwest region, the lowest one is in the Northwest region. The Southeast region and the Red River Delta give a higher accuracy than the Northeast, North Central, South Central and Central Highlands region. In addition, 1804 levelling routes in 8 experimental areas throughout Vietnam have been evaluated for accuracy. It is the first time the accuracy of the GAO 2012 model has been determined in Vietnam. These are useful information for the conversion from ellipsoidal height to normal height as well as for the purpose of building a local geoid.