GNSS timing receiver with synchronization of raw GNSS measurements to an external timescale. Synchronization is achieved by using a hardware Time Interval Measurement Unit (TIMU). The TIMU measures time intervals between two pulse signals and makes additional processing of these measurements. The first pulse signal is generated inside the GNSS receiver. The second pulse signal is the external pulse signal generated by an external time reference device. This time interval is used to control the time instant when the output GNSS measurement will be taken. In the first embodiment all actual GNSS measurements are physically taken at time instants indicated by external pulse signal. These measurements are used as output GNSS measurements. In another embodiment all actual GNSS measurements are taken at their default time instants indicated by internal pulse signal. But output GNSS measurements are calculated at the time instants indicated by the external pulse signal.