Patent ID: 8630147
Filing Date: 2014-01-14
Classification: G01S

Abstract:
1. A method of determining a position where work is done in a space surrounded by surfaces, characterized in that the position where work inside the space is done is located on a sidewall, wave receivers capable of receiving an acoustic wave signal are placed at three or more points, which are on the same plane substantially parallel to the sidewall but not collinear with one another and whose position coordinates are known, a signal is transmitted from a wave transmitter capable of transmitting an acoustic wave and placed at a position where work is done on the sidewall in the space, respective arrival times of the signal at the three or more wave receivers not collinear with one another are measured, and position coordinates of the wave transmitter are determined using the arrival times and the position coordinates of the three or more wave receivers, wherein the wave transmitter capable of transmitting the acoustic wave is placed at the position where work is done on the sidewall in the space, and wave receivers capable of receiving the acoustic wave are placed on a scaffold provided for passage of a worker with a space from a wall surface on which the wave transmitter is placed.