A test device determines error in a fronthaul network of a radio access network. A first Global Navigation Satellite System (GNSS) receiver receives GNSS signals from a GNSS satellite through a reference GNSS signal distribution system (GSDS) having a known signal propagation delay. The first GNSS receiver calculates and outputs a corresponding reference One Pulse Per Second (1 PPS) signal. A second GNSS receiver receives the GNSS signals through a device under test including a GSDS having an unknown signal propagation delay. The second GNSS receiver calculates and outputs a corresponding DUT 1 PPS signal. The test device determines the unknown signal propagation delay of the DUT by comparing the reference 1 PPS signal to the DUT 1 PPS signal.