河川堤防計測へのモバイルマッピングシステムの適用

摘要

本研究では，FKP方式で自己位置を求めているMMSを用いた河川堤防計測を行ない，高精度での計測方法を検討するために，FKP方式とRTK法により電子基準点を固定局として用いた場合と，新たに固定局を設けた場合のMMSの車両の自己位置の精度を求めた。次にその結果に基づいて堤防天端の標高および堤防の天端から法面方向の位置精度を確認し，計測手法の妥当性を考察した。最後にレーザ光が堤防の地表面に当っている点群の抽出方法を検討し，堤防断面形状を作成するための手法を提案してその有効性を確認し，次のことを明らかにした。%Recently Mobile Mapping System (MMS) is used for variety applications such as three-dimensional road facility mapping, road maintenance and disaster risk management.The application of MMS to maintenance and management of river embankments has also been studied so far. The three-dimensional coordinates of the laser point cloud data obtained from MMS are calculated based on the position and orientation of MMS that are measured by GNSS, IMU and odometer. Analysis of the position of MMS is carried out by RTK method or networked RTK method such as FKP (Flachen Korrektur Parameter) method and VRS (Virtual Reference Station) method. In the GNSS analysis, longer base line decreased accuracy due to ionospheric and tropospheric delay. In this study, we verified the difference of positioning accuracy depending on the GNSb analysis method and considered the optimal measurement conditions to apply MMS to monitoring the river embankment. In addition, based on the three-dimensional laser point cloud, we investigated the accuracy of the height of the embankment crest and the profile of the river embankment by using our proposed methods. In this paper, we demonstrate the required measurement conditions and the effective data processing for the river embankment measurement by MMS.