![]() Specific use cases include the synchronization of power lines, millisecond share trades, and telecommunication networks (Lisi 2015). Next to positioning, timing is a key application of GNSS with ever-increasing relevance for today’s society. For BeiDou, a slightly worse accuracy of 3 ns is obtained for a single timing laboratory over 9 months. Over the 1.5 years covered in the study, an accuracy of 1.8 ns for GPS and 2.5 ns for Galileo is demonstrated. The overall quality of the PPP-BCE-derived receiver clock offsets from UTC is assessed using calibrated receivers at various timing laboratories along with BIPM-provided UTC-UTC(k) measurements. Furthermore, access to GNSS-specific UTC realizations can be obtained through predictions of the UTC offset from GNSS system time as provided in the broadcast ephemerides of individual constellations. In the absence of prior calibrations, 0.5 ns consistency across different stations is achieved for GPS, Galileo, and BeiDou-3 after adjustment of systematic biases in comparison with calibrated reference stations or broadcast XYTO values. Using calibrated timing receivers, the method is shown to provide estimates of the GNSS-to-GNSS time offsets (XYTOs) with an accuracy at the 2 ns level. #UTC TIME VS GPS TIME OFFLINE#It combines the use of broadcast ephemerides with low-noise carrier-phase observations for accessing GNSS system time scales and Coordinated Universal Time (UTC) with improved precision, and can be employed on stationary as well as mobile receivers in offline or real-time analyses. The RT3000 v3 was in GPS mode but the Hesai Pandar40P was expecting timestamps in UTC.The application of precise point positioning with broadcast ephemerides (PPP-BCE) is discussed as an alternative to the established all-in-view technique for multi-GNSS time transfer. Time synchronisation was achieved using PTP. This is done in seconds.ĭuring internal testing of the PTP feature, a data was collected with a Hesai Pandar40P and an RT3000 v3. This is done by opening 'Processing options' from the Files tab using the 'PTP Time Synchronisation Correction’ box. If PTP is being used to synchronize a LiDAR with an OxTS, it is possible to change the time mode in OxTS Georeferencer if the wrong time mode was used during the data collection. To avoid this, use the corresponding custom offset command instead of the time mode command. This results in an 18 s offset when UTC mode is used. Note: Some PTP devices that we have tested with ignore the Leap second information that is output alongside the timestamp. Similarly, the custom offset under GPS can also be used to access time modes not listed above by finding the correct offset (which will be the number of seconds between the different epochs). Here you can see that the different time modes can be reached by adding different offsets to the GPS timestamps. This is done by selecting the relevant time Epoch under the PTP tab in Interfaces on NAVconfig. If the PTP device being synchronised to the OxTS device does not use the GPS epoch, it is possible to configure the OxTS device to output PTP timestamps from a different epoch (this will not change the timestamps in the NCOM stream). To get the correct date and time from a timestamp, it is important to know which epoch is being used. Time in seconds since the PTP epoch ( 23:59:51 TAI), Time in seconds since the Unix epoch ( 00:00:00 UTC), Time in seconds since the Unix epoch ( 00:00:00 UTC). Time in seconds since the GPS epoch ( 00:00:00 UTC), same as NCOM. Here is a list of commonly used time modes: GPS Not all devices expect timestamps to be in the GPS epoch. By default, when an OxTS device is used with PTP, it will be using the GPS epoch. This is know as the GPS epoch and from this the device can calculate the current date and time. The time that OxTS devices receive from the satellites is the number of seconds since midnight January 5th - January 6th 1980. OxTS devices get their time solution from GNSS satellites which use very accurate atomic clocks. PTP is a new feature that allows other PTP compatible devices to synchronize their clock to the clock of an OxTS device. ![]()
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