Abstract: The nuclear power plant radioactive source composite positioning online monitoring system developed and constructed in this research and development combines the radioactive source management work with Ultra-Wide Band ( UWB) technology and Beidou positioning technology to achieve seamless and high-precision tracking both indoors and outdoors. For outdoor scenarios, the Horizontal Dilution of Precision (HDOP) factor is adopted for evaluation, and Kalman filtering is used to enhance the data reliability. For indoor scenarios, Time Division Multiplexing Access (TDMA) technology is innovatively applied to the UWB Time Difference of Arrival (TDOA) positioning system. This maximizes the concurrent tolerance of the system while achieving a high-precision positioning of ±10 cm, meeting the precise monitoring requirements for the tiny movements of radioactive sources. With the help of 5G real-time transmission dedicated to nuclear power plants, intelligent and digital full-process control has been successfully achieved, ensuring the safety of radioactive source storage, transportation and usage. The introduction of 3D technology enhances the intuitiveness and efficiency of monitoring, providing a new approach for the safety supervision of radioactive sources in nuclear power plants.

Key words: radioactive sources, internet of things, positioning, 3D