exception while reading observation file

hi,

on the observation file while performing data=gr.load('~/data_MO.rnx')

I get an error

ValueError                                Traceback (most recent call last)
<ipython-input-13-cfa21750ce07> in <module>()
----> 1 data=gr.load('~/data_MO.rnx')

~/anaconda3/lib/python3.6/site-packages/georinex/base.py in load(rinexfn, out, use, tlim, useindicators, meas, verbose, overwrite, fast, interval)
     67                         useindicators=useindicators, meas=meas,
     68                         verbose=verbose,
---> 69                         overwrite=overwrite, fast=fast, interval=interval)
     70     elif rinexfn.suffix == '.nc':
     71         # outfn not used here, because we already have the converted file!

~/anaconda3/lib/python3.6/site-packages/georinex/base.py in rinexobs(fn, outfn, use, group, tlim, useindicators, meas, verbose, overwrite, fast, interval)
    192                         useindicators=useindicators, meas=meas,
    193                         verbose=verbose,
--> 194                         fast=fast, interval=interval)
    195     else:
    196         raise ValueError(f'unknown RINEX {info}  {fn}')

~/anaconda3/lib/python3.6/site-packages/georinex/obs3.py in rinexobs3(fn, use, tlim, useindicators, meas, verbose, fast, interval)
    134     data.attrs['rinextype'] = 'obs'
    135     data.attrs['fast_processing'] = 0  # bool is not allowed in NetCDF4
--> 136     data.attrs['time_system'] = determine_time_system(hdr)
    137     if isinstance(fn, Path):
    138         data.attrs['filename'] = fn.name

~/anaconda3/lib/python3.6/site-packages/georinex/common.py in determine_time_system(header)
     63         ts = header['TIME OF FIRST OBS'][48:51].strip()
     64     else:
---> 65         raise ValueError(f'unknown file type {file_type}')
     66 
     67     return ts

ValueError: unknown file type

However other function rinexheader() works fine on the file.

I am using GeoRinex version on the main branch, xarray version 0.20.2, numpy version 1.20.1, python-dateutil version 2.8.1, and rinex file created using rinex 3.03.

Please suggest.

Kind regards

geospace-code / georinex

exception while reading observation file #80