1. Asama, H., Sato, M., Kaetsu, H., Ozaki, K., Matsumoto, A. and Endo, I., Development of an omni-directional mobile robot with 3 DoF decoupling drive mechanism, Journal of the Robotics Society of Japan, Vol.14, No.2(1996),pp.249-254 (in Japanese).
2. Hirano, Y., Detection and estimates of tree root system using ground penetrating radar, SYSTEMS, CONTROL AND INFORMATION, Vol.62, No.12(2018), pp.502-507 (in Japanese).
3. Imai, T. and Yamada, S., Development and applicability of chirp radar for the extending of the penetration depth, Jour. Japan Soc. Eng. Geol., Vol.58, No.5 (2017), pp.324-330 (in Japanese).
4. Kataoka, Y., Mizukami, M. and Mochizuki, S., Verification of self-positioning accuracy of omni-directional autonomous mobile robot using sensor fusion, Proceedings of the 59th JSME Hokkaido Branch Conference(2022), pp.15-19 (in Japanese).
5. Ministry of Land, <https://www.mlit.go.jp/sogoseisaku/infra/> (accessed on 24 December, 2023)