Comparison of two digital elevation models generated from UAV systems and GNSS instruments

Resumen

The technological advance and the appearance of UAVs (unmanned
aerial vehicle) in the last decades marked a new path in topographic
surveys and measurements of three-dimensional coordinates of
points. The generation of Digital Elevation Models (DEM), orthomosaics
and cartographic products generated through UAV systems is an
alternative tool in the urban planning or the study of a certain area. In
this work, two DEMs were generated, one through data obtained with
a UAV. For this, an autonomous flight was made, at a flight height of 60
meters, with a cruising speed of 8 m / s, longitudinal overlap of 80 %
and lateral overlap of 70 %. With this, images with 2.6 cm / pix of spatial
resolution were obtained. The other model was made using data taken
with a South Galaxy G1 Plus 220-channel GPS / GNSS (Global Position
System - Global Navigation Satellite System) receiver that allows
better precision in planialtimetric coordinates. It is a dual frequency
equipment (L1 / L2) and receives information from the GPS, GLONASS,
BEIDOU and GALILEO constellations. The results were compared to
assess the precision of the products generated. The results obtained
in this work detect significant differences in terms of the density of
points that can be obtained to make the DEM. Both technologies can
be efficient depending on the objective of the work. When the surface
to be surveyed presents a uniform slope, both instruments can achieve
similar results, but when the surface to be surveyed has depressions
or high areas, different results are achieved. The DEM obtained with
the UAV is better adapted to the topography of the land.