Hello,
is planned to integrate a conversion from Kelvin to Fahrenheit?
Would be great!

Thank you
Fabian

If RMC is missing fields I would think those values should not be set to 0.0 and either set to null or not set.

eg. navigation.variation should not be set to 0.0 if RMC sentence is missing either of the two required values.
I'm having the issue w/ downstream apps/plugins displaying magnetic / true north incorrectly.

I could do a PR if that would help

timestamp expects the time to have exactly 6 digits e.g. 112233 which makes
11 hours
22 minutes
33 seconds.

But gps receivers like u-blox send the time in the format containing milliseconds: 112233.44 which would be translated to
11 hours
22 minutes
44 seconds instead of 33 seconds
The functions should not take the last two digits as seconds asuming that the string is 6 digits long!

Please include milliseconds in your algorithm and check for both formats: 6 digits and 9 digits!

If timestamp() is called with no parameters the returned date is now minus one month:

   } else {
      var dt = new Date();
      year = dt.getUTCFullYear();
      month = dt.getUTCMonth();
      day = dt.getUTCDate();
    }

    /* construct */
    var d = new Date(Date.UTC(year, (month - 1), day, hours, minutes, seconds));

Probably the fix can be:

   } else {
      var dt = new Date();
      year = dt.getUTCFullYear();
      month = dt.getUTCMonth() + 1;  // [1;12] as in NMEA
      day = dt.getUTCDate();
    }

    /* construct */
    var d = new Date(Date.UTC(year, (month - 1), day, hours, minutes, seconds));

Much of what is in the package can be found elsewhere in conversion specific packages. One example is convert-units. It's setup in a way where it's easy to add additional conversions. I have a pull request in for some nautical units.