Time distribution device with multi-band antenna
Systems and methods for detecting the failure of a precision time source using an independent time source are disclosed. Additionally, detecting the failure of a GNSS based precision time source based on a calculated location of a GNSS receiver is disclosed. Moreover, the system may be further configured to distribute a time derived from the precision time source as a precision time reference to time dependent devices. In the event of a failure of the precision time source, the system may be configured to distribute a time derived from a second precision time source as the precision time signal during a holdover period.
1. A method comprising:
receiving at a single, multi-band antenna, a first time signal from a first time source, the first time signal having a corresponding first error bound related to accuracy of the first time signal;
receiving at the single, multi-band antenna, a second time signal from a second time source separate from the first time source, the second time signal having a corresponding second error bound related to accuracy of the second time signal;
comparing the first time signal with the second error bound of the second time signal;
when the first time signal falls outside of the second error bound, determine a failure of the first time signal;
when the first time signal falls within the second error bound, determine that an error of the first time signal is acceptable relative to the second time signal; and
when the first time signal is determined acceptable, outputting a first output time signal from the first time source to an electronic device (ED) protecting an electric power delivery system using the first output time signal.
2. The method of 1 , further comprising:
outputting a second output time signal from the second time source in place of the first output time signal in response to detecting a failure of the first time source.
3. The method of 1 , wherein the first and second sources comprise at least two selected from the group consisting of: a global navigation satellite system (GNSS), a NIST signal, a WWVB signal, a WWV signal, and combinations thereof.
4. A time distribution device comprising:
a multi-band antenna configured to
receive a first time signal from a first time source, the first time signal having a corresponding first error bound related to accuracy of the first time signal; and
receive a second time signal from a second time source, the second time signal having a corresponding second error bound related to accuracy of the second time signal;
a time quality module configured to:
compare the first time signal with the second error bound of the second time signal;
when the first time signal falls outside of the second error bound, determine a failure of the first time signal; and,
when the first time signal is within the second error bound, determine that an error of the first time signal is acceptable relative to the second time signal; and,
an output configured to provide an output time signal corresponding with the first output time signal when the first time signal is determined acceptable.
5. The time distribution device of claim 4 , wherein at least one of the first and second time sources includes a global navigation satellite system (GNSS).
6. The time distribution device of claim 4 , wherein one of the first and second time sources includes a WWVB.
7. The time distribution device of claim 4 further comprising, an indicator configured to notify a user when an error condition is detected.