Nanosecond time synchronization of distributed detectors

At the Pierre Auger Observatory, the surface detectors used to detect and measure cosmic-ray air showers are placed in a triangular ground pattern with a 1500 m spacing, covering a total area of about 3000 km2. Time synchronization of such distributed detectors to very high accuracy on the nanosecond scale is challenging. Currently, ordinary GPS receivers are used, which simply and independently report the GPS-time/UTC-time at their current position. Achieving 1 ns relative time accuracy between detectors would prove very useful, for example in the context of the measurement of radio emissions from extensive air showers. Accurate timing information of an event recorded by an array of radio antennas would enable intriguing possibilities for radio-interferometric analyses of cosmic-ray air showers.
This talk will report on recent findings regarding wirelessly communicating GPS modules with currently non-standard capabilities, promising 3 cm accurate relative positioning and thus potentially 1 ns relative timing accuracy.