GNSS satellites are equipped with atomic clocks which utilize internal oscillators to deliver timing measurements accurate to 20 ns. This provides system integrators with the world's most precise, stable source of timing information. NovAtel's timing solutions are suited for a wide range of applications where accurate timing is essential in managing workflows and data. Applications for precise GNSS time include:
System time synchronization applications
Frequency/phase synchronization applications
System time synchronization can be achieved using:
All of NovAtel receivers' data messages contain time stamped information. This time stamp consists of a GPS reference week number (the week number since January 5th, 1980) and a Time of Week (TOW) value that represents the number of seconds from the Week rollover point at the Saturday night/Sunday morning boundary. The TOW is output with a resolution of 1 ms.
TIME log provides several time related pieces of information including the UTC offset (offset of GPS reference time from UTC time) and the estimated receiver clock offset from GPS reference time.
Binary data can also be easily converted into well recognized industry timing formats. For example: RINEX and the Group on GPS Time Transfer Standards (GGTTS) data format for common view time transfer purposes.
Timing through Strobe Connection:
PPS and Variable Frequency (VARF) Output
External Oscillator Input:
The GPS receiver, by default, steers the internal oscillator. It can also be commanded to control an external reference oscillator. If the receiver is configured for an external reference oscillator and configured to adjust its clock, then the clock steering loop attempts to steer the external reference oscillator through the use of the VARF signal.
A high precision external oscillator can be utilized with a GNSS receiver, with GNSS measurements generated based on the external oscillator time and frequency. In this case, users can monitor the offset and drift of their external oscillator through the analysis of the GPS measurements made using their reference clock and frequency inputs.
Time Synchronization (T-Sync) Circuitry:
NovAtel receivers are designed to accept external clock products (5 or 10 MHz frequency input and 1 PPS) and to lock the internal clock to these signals. The T-Sync Circuitry enables the receiver's internal clock to reliably reinitialize to the external clock products after a power cycle or reset. When the receiver reinitializes from a power cycle or reset, no start-up to start-up bias shift will occur.
When choosing a timing solution, consider the following needs of your application: