This paper relates to the implementation of moving object position estimation by Pulsed LiDAR that can detect objects with high precision, speed, and spatial resolution. LiDAR measures the distance by calculating a return travel time when target is reflected. The retro-reflector, regardless of incident angle, can be reflected horizontally in the incident direction. This algorithm proposes a new approach method using LiDAR and retro-reflectors. According to the above algorithm, position can be determined by automatically detecting 90% of the reflected return beam intensity from moving objects to which the retro-reflector is attached. When this algorithm was applied indoors, it was possible to locate the position of the scanner accurately within ±5 mm error in 2,500 × 2,500 (mm) space. Also, it can detect a space of up to 5,000 × 5,000 (mm), making this an effective method for determining the position of a moving object in indoors.

This paper proposes an IMU method for location tracking in power plants and indoor environments without GPS. IMU-based sensors use accelerometer, angular accelerometer, earth magnetometer, and altimeter. It is a method for recognizing the movement of pedestrians or moving objects. However, errors can be caused, as noise and bias increase due to long-term measurement. VIO-SLAM type sensor T265, which uses a combination of cameras and IMU, and can accurately track paths in invisible spaces, is used in this study. In addition, this type of sensor can be corrected in real time with a filter function inserted into the sensor and errors can be minimized. As a comparison experiment with the encoder, it is possible to evaluate the location of the scanner within a ±10 mm error from the actual distance in 1,500 × 700 (mm) space. The usefulness of this method is verified by measuring real specimens of boiler pipes and tubes, which are the major components of power plants.