Read conPhs data with ROPP

[Ian Culverwell]

Xinjia Zhou at NOAA/NESDIS informs me, in Helpdesk Enq 417, that on 2020.140 (May 19) UCAR changed the format of the conPhs COSMIC-2 excess phase datafiles. (Before this time, conPhs appears to be the same format as atmPhs: ucar2ropp can read them both, for example.) An example of the new format file is attached. We should probably be able to read this with ROPP. I asked Xinjia if any documentation on the new conPhs file format is available.

[Ian Culverwell]

conPhs_C2E1.2020.140.00.32.r17_0001.0001_nc

[Ian Culverwell]

Xinjia points me to the documentation at

​https://cdaac-www.cosmic.ucar.edu/cdaac/cgi_bin/fileFormats.cgi?type=conPhs

Key thing:

If the field 'orbtime' is present, then this conPhs file used 
low rate (1 second) orbits instead of 50- or 100-Hz orbits to 
save space. Instructions for reconstructing the high rate 
orbits are contained in the 'orbtime' and 'txmitLR' 
attributes.

These attributes say

		orbtime:long_name = "Low rate time used for orbit products.  Allows interpolation of orbit positions to high rate time" ;

and

		txmitLR:long_name = "Low rate time of GNSS signal transmission.  Used for reconstructing high rate GNSS orbits:  First txmitHR = linear_interp(timeLR, txmitLR, time+tstart), then GNSS_hr_x = poly_interp(xGnssLR, txmitLR, txmitHR).  Do the last step also for Y and Z components." ;

So hopefully not too difficult.

[Ian Culverwell]

Make this "whenever" (the demand arises).