Utilization of Mean Dynamic Topography for GNSS-Leveling Applications (Case Study: Jakarta Area)

Abstract

Conventionally, the determination of height that has physical meaning for a location or area can be determined geodetically by measuring the height difference relative to a reference point using the spirit-leveling method. This type of height, orthometric height, is essential to explain any physical phenomena, e.g., determining which direction fluid flows, which is used in many scientific and engineering applications. The coverage area is one limitation of conventional leveling, using waterpass precise leveling. The wider the coverage area, the more time and cost-consuming it will be. Another alternative to determine the height at a particular location is using the Global Navigation Satellite System – Leveling (GNSS-Leveling) method, which can be used to resolve the drawbacks of the previous method. GNSS-Leveling method is able to provide an efficient height determination solution if an accurate geoid undulation model and Mean Dynamic Topography (MDT) model are available over the area of interest. MDT is the height deviation between the geoid surface and the mean sea surface (MSS). Information related to geoid undulation and MDT is important to ensure any GNSS-Leveling measurement referring to the local Mean Sea Level (MSL) surface, which is widely needed in various applications. Applying the EGM2008 geoid model and altimetric-derived MDT solution to GNSS-Leveling measurements in the Jakarta area, the average orthometric height difference relative to the reference value is estimated to be about 5 cm. This shows that GNSS-Leveling is a promising solution when combined with geoid and MDT models.