Author:
Mori A.,Seguchi E.,Futemma A.,Iwai T.,Sanada Y.
Abstract
Abstract
Four global navigation satellite system (GNSS) receivers
were installed in a helicopter to reduce positioning errors in
aerial radiation monitoring. The effect of positioning errors on the
conversion of the counting rate of the detector to the ambient dose
equivalent rate at the ground level was evaluated. The positioning
results obtained by receiving the centimeter-class augmentation
signal known as the L-band experiment, which the Quasi-Zenith
Satellite System generates on an experimental basis for a limited
time, were used as the reference values. A comparison between
horizontal and vertical positioning errors among four receivers
demonstrated that the vertical errors were larger than the
horizontal errors. They did not differ among receivers, whereas the
horizontal errors varied according to the characteristics of the
receivers, particularly in mountainous areas; the errors tended to
be larger when the terrain change at the measurement point was
larger. The median effects of the vertical and horizontal errors on
the calculated values of the radiation dose rate at the ground level
were 3%–6% and 1%–5%, respectively, and the maximum possible
effect of the positioning error was 20%–32%. The fact that the
receiver with the highest number of available satellites had larger
errors than the other receivers indicated that the elevation angles
of satellites and the augmentation signals play an important role in
improving the positioning accuracy when the number of available
satellites reduces in mountainous areas. This study has provided
insight into selecting a suitable GNSS receiver for surveying by
vehicles such as helicopters, aircraft, and drones, which are
required to perform 3D positioning in complex terrains.
Subject
Mathematical Physics,Instrumentation