GB/T 42579-2023 in English

1. Background and significance of the standard

BeiDou satellite navigation system time (BDT) is the core component of the BeiDou system. Its accuracy and stability are directly related to the system's positioning, navigation and timing services. This standard was proposed by the Equipment Development Department of the Central Military Commission and was managed by the National BeiDou Satellite Navigation Standardization Technical Committee, ensuring its authority and applicability.

2. Core content of the standard

The BeiDou system time uses the International Atomic Time (TAI) second as the basic unit, without leap seconds, and the starting epoch is UTC 0:0:00 on January 1, 2006. The deviation between BDT and UTC is always kept within 50 nanoseconds.

3. Time representation

The Beidou system time uses two representation methods:

• Weekly cycle method: Uses WN (week count) and SOW (second count within the week). For example, '722:399270' represents 722 weeks and 399270 seconds in Beidou time.
• Yearly cycle method: Uses YN (year count) and MOY (minute count within the year). For example, '13:7284894' represents 13 years and 7284894 minutes in Beidou time.

4. Comparison with other time systems

5. Implementation Suggestions

In actual applications, it is recommended that users:

1. Ensure that the device supports the time synchronization function of the BeiDou system.
2. Regularly calibrate the time to maintain accuracy.
3. Refer to the BDT-UTC parameter in the navigation message for time conversion.
4. Combined with leap second processing mechanism in scenarios where high-precision time service is required.