Topographical Survey Using Drone Technology Establishment of Control Station by DGPS Drone Image of Baglung Portal Area Drone Image of Narethati Portal Area Proposed baglung Portal Proposed Narethati Portal The Topographical Survey (for portals and tunnel alignment) of Baglung-Beu-Narethati Road Tunnel Project has been completed using Drone Technology with necessary ground control stations establihsed using DGPS. The drone survey proven to be one of the cost effect method with required accuracy especially when there is