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Obtaining leveled heights by GPS leveling. Case study: Morona - Ecuador

Abstract:

The aim of the study was to demonstrate the applicability of GPS leveling to obtain accurate leveled heights for engineering purposes, in the canton of Morona, Ecuador. Two working scales were evaluated: cantonal (macro) and urban (micro), where the known vertices from which the height value was determined were points that belong to the local geodesic network of the canton. Based on the analysis of the geoid undulation gradient, 5 homogeneous zones of the gradient variation were defined; GPS leveling was applied in the two zones (zone 4 and 5) that had geodesic vertices and that also cover a larger area of the canton. The geoid undulation gradient values in the study area were highly variable, with errors of up to 24 mm/km. At the cantonal scale, errors were reached between 12.19 cm - 1.27 cm at 30 Km - 5.1 Km in zone 4, and 38.48 cm - 8.33 cm at 13 Km - 2.7 Km in zone 5, while on an urban scale, errors of 2.48 cm - 0.14 cm were found at 1.07 Km - 0.19 Km, respectively. Using GPS leveling, useful results are obtained for engineering jobs and geoscience jobs in general, that require the determination of leveled heights quickly and accurately. For the correct application of this technique, two determinants must be considered: the baseline distance and the geoid undulation gradient.