The transmission signal is transmitted by LoRa/4G/5G or ultra-wideband technology. When the signal is transmitted to the signal display screen, the change value of the signal is observed and recorded, the status is displayed and predicted in real time, and the early warning is issued in advance. Using LoRa and other ultra-wideband signal transmission, relay amplification, topology analysis and other transmission technologies to transmit signals reliably and effectively, through the signal transmission system, the finite space threshold, personnel or equipment moving track, position, distance, etc., can be calculated and predicted, and the finite space multidimensional information can be visually presented in the terminal of the guardian outside the limited space.