Time difference of arrival measurement system based on GNU Radio and USRP

High-precision Time Difference of Arrival (TDOA) measurement technology is a core technology in numerous scientific research and exploration endeavors. Addressing the issues of interferometry relying on large-scale equipment and being difficult to deploy, this paper designs a TDOA measurement system that implements signal interferometry on a softwaredefined radio (SDR) platform. The system consists of a USRP B210 and the GNU Radio software development platform. Utilizing wired signal transmission, the received signals undergo operations such as down conversion, sampling, and frequency domain conversion before the data is saved. Subsequently, MATLAB software is employed to calculate the time difference values. To mitigate the impact of random noise, the received signals are processed with varying accumulation times for testing, and the optimal accumulation time for the experiment is selected. Multiple TDOA measurements are conducted under varying differences in signal transmission distances, with a maximum error of less than 2.5 ns. This system can be applied in fields such as direction finding and positioning.