Existing RTLS solutions are mostly based on either wireless technologies, fiducial markers, or Lidar-based simultaneous localization and mapping (SLAM), and inevitably suffer from some drawbacks such as low accuracy, reliance on existing facilities, labor-intensive environment instrumentation, or high economic cost. This paper introduces an ORB2 RGB-D SLAM based indoor RTLS that can be readily adapted and applied to building or civil infrastructure applications while addressing the above limitations. Besides the original sparse feature map built by the visual SLAM (vSLAM), the proposed system builds and maintains an additional 2D occupancy grid map (OGM) and overlays it with real-time 2D camera pose and virtual laser scan for 2D localization. These designs not only allow users to interact with the system but also open up the possibilities of path planning and continuous navigation based on feature-based vSLAM. The localization accuracy of the system is evaluated with a marker-based method, which proves its feasibility and applicability in indoor building and construction applications.