A team of four electrical engineer students developed a multilateral radar system. Everyone had a subsystem to develop. As a member of the team, my task was to develop a synchronization device. A multilateral radar system based on distributed receivers and measuring time differences of received signals. The time measurement based on the synchronization devices at every receiver stations. The most critical part of the multilateral system is the time measurement subsystem, because the accuracy depends on the uncertainty of time measurement. I developed a GPS based reference oscillator (GPS Disciplined Oscillator), which can supply phase synchronous clock at different locations. Measurements prove, that between two of any GPSDOs, the clock signals are in the same phase, only medium term phase noise affects that. According to the measurement results in the worst case condition the noise is equivalent with 35 ns RMS white phase noise.Simulations show, that time uncertainty of the GPSDOs will cause less than 100 m RMS position uncertainty inside the observation area.