Time transfer via single-record TDoA measurements of GNSS satellites using direct cross-correlation and relative pilot code phases

Radar systems are evolving towards distributed receiver networks. As individual stations might be separated too far to install a cable link, novel methods are required to synchronise individual data records in the time domain. State-of-the-art GNSS receivers disciplining a highly stable oscillator are able to output a timing signal with several nanosecond accuracy solely using non-proprietary signals. However, they typically require a stable environment and become a major cost factor for receiver networks with a high number of nodes. A method is presented to passively synchronise data records via GNSS raw signals in a single record requiring only a GNSS antenna, an analogue-to-digital converter and computation hardware. The clock bias is estimated via the common view method with either full raw signal correlation or software-based code correlation of individual signals from the GPS, Galileo and BeiDou constellation with sub-nanosecond precision.