ultra-wide band technology has become a standard in accurate ranging and localization as well. The technology can be
used in indoor positioning systems to solve problems of GPS in indoor environment. In this paper we develop a system that can measure accurate ranges to be used in sensitive range applications. The system integrates the DWM3000 module with the nRF52840 developmental kit. The proposed system can be used in different applications. One of these applications is the smart gate system which is discussed below. Accuracy of 10 cm is achieved by the proposed system.