Returned datetime is not accurate

[shambakey1]

Hi

I'm trying to convert the datetime parameter from the multi index column, but the conversion to "year-month-day hour-min-sec" is not accurate with me. I'm not sure what I'm doing wrong. For example, for the file "https://cddis.nasa.gov/archive/gnss/products/ionex/2022/001/igsg0010.22i.Z", the epoch is for date 2022-01-01. I read the file using the following syntax:

import gnssanalysis as gns
import datetime

d=gns.gn_io.ionex.read_ionex(<file path>)
datetime.datetime.fromtimestamp(d[0].index.values[0][0])

The output of the previous command is

datetime.datetime(1992, 1, 1, 14, 0)

Which is NOT 2022. I tried to change the command to

datetime.datetime.utcfromtimestamp(d[0].index.values[0][0])

But still the same result.
I wonder what I'm doing wrong.

Regards

[seballgeyer]

Hi

You will need to use the following function

gns.gn_datetime.j2000_to_pydatetime(d[0].index[0][0])

this will return

datetime.datetime(2022, 1, 1, 0, 0)

inside gnssanalysis datetime are stored as number of seconds since J2000 (01-01-2000T12:00:00) whereas
the datetime library has its 0 being 01-01-1970T00-00-00, the difference of origin time explain the difference in results.

Best regards

Sébastien

[shambakey1]

Thank you very much. This solved it