Scale
Time scales, zones, and flight time.
Time scale tools convert between the clocks that aviation, GNSS, and astronomy keep: local time and UTC (Zulu), GPS week and seconds, Julian dates and day of year, and flight time in hours and minutes or decimal hours. Pilots use them to turn a local departure time into Zulu and to log block time. GNSS users and surveyors use them to match receiver time to UTC and name RINEX files. Start with local time to UTC, which handles daylight saving gaps and the date change. One pitfall: GPS time runs ahead of UTC by the leap seconds added since 1980, now 18 seconds.
I want to convert local time to UTC, or check a zone's rules
- Local time to UTC (Zulu)
Converts a local time to UTC and Zulu time with an IANA time zone or a UTC offset, or UTC to local, handling daylight saving gaps and overlaps and showing the date change.
- Time zone rules at a date
The UTC offset, abbreviation, and daylight saving state of an IANA time zone at a moment, and when it next changes.
I want to convert between UTC and GPS time
- UTC to GPS week and seconds
The GPS week, seconds of week, 10-bit week and rollover era, and the GPS − UTC and TAI − UTC offsets for a UTC time.
- GPS week and seconds to UTC
The UTC time for a GPS week and seconds of week, including 10-bit weeks with their rollover era.
I want to find a Julian date or day of year
- Julian date, MJD, and day of year
The Julian date, modified Julian date, and day of year for a UTC time (or the time for a JD or MJD), with the RINEX daily file name.
I want to log flight time
- Block time (out to in)
The time between out and in (block time or flight time), across midnight and across UTC dates, in hours and minutes and decimal hours.
- Decimal hours to hours and minutes
Converts decimal hours to hours and minutes (1.3 h is 1:18, not 1:30) and back.