MATLAB: Using fget1 to read text file. Need help sorting data

fgetlMATLABsorttext file

Using the fgetl function I'm making a program to read this text file line by line. I need to be able to seperate the data entries from each other and store them in their own designated variables. You will see in the text file that some of the data entries start with a G (GPS) and other ones start with an R (GLONASS). I need to be able to get the program to recogize that first character that signifies GPS or GLONASS and then proceed to store the data entries in between. The number of data entries and lines of data are constant for both constellations. GPS has 8 lines and 34 data entries. GLONASS has 4 lines and 22 entries. 
G32 2020 01 03 22 00 00 1.747743226588E-04 1.091393642128E-11 0.000000000000E+00
     3.500000000000E+01-1.318750000000E+01 4.651979487904E-09 5.385931295143E-01
    -7.767230272293E-07 3.395725856535E-03 9.786337614059E-06 5.153669069290E+03
     5.112000000000E+05 1.862645149231E-09 1.499495835472E+00 3.725290298462E-08
     9.563698279564E-01 1.892187500000E+02-2.550865203809E+00-8.079265105250E-09
    -1.246480492344E-10 1.000000000000E+00 2.086000000000E+03 0.000000000000E+00
     2.000000000000E+00 0.000000000000E+00 4.656612873077E-10 3.500000000000E+01
     5.040180000000E+05 4.000000000000E+00
R01 2020 01 03 00 15 00 5.505327135324E-05 0.000000000000E+00 4.320000000000E+05
    -1.407114599609E+04 6.327390670776E-01-0.000000000000E+00 0.000000000000E+00
    -1.985983984375E+04 8.451271057129E-01-1.862645149231E-09 1.000000000000E+00
    -7.659376464844E+03-3.354722023010E+00 0.000000000000E+00 0.000000000000E+00
R01 2020 01 03 00 45 00 5.505420267582E-05 0.000000000000E+00 4.338000000000E+05
    -1.228681494141E+04 1.356384277344E+00-9.313225746155E-10 0.000000000000E+00
    -1.796078857422E+04 1.222489356995E+00-1.862645149231E-09 1.000000000000E+00
    -1.332407470703E+04-2.898560523987E+00 9.313225746155E-10 0.000000000000E+00
R01 2020 01 03 01 15 00 5.505513399839E-05 0.000000000000E+00 4.356000000000E+05
    -9.198476562500E+03 2.062785148621E+00-9.313225746155E-10 0.000000000000E+00
    -1.561752148438E+04 1.336973190308E+00-9.313225746155E-10 1.000000000000E+00
    -1.795952929688E+04-2.218539237976E+00 1.862645149231E-09 0.000000000000E+00
R01 2020 01 03 01 45 00 5.505699664354E-05 0.000000000000E+00 4.374000000000E+05
    -4.937781250000E+03 2.641427993774E+00-9.313225746155E-10 0.000000000000E+00
    -1.329891015625E+04 1.200849533081E+00-0.000000000000E+00 1.000000000000E+00
    -2.120773779297E+04-1.367164611816E+00 1.862645149231E-09 0.000000000000E+00
R01 2020 01 03 02 15 00 5.505792796612E-05 0.000000000000E+00 4.392000000000E+05
     1.769560546875E+02 2.998314857483E+00-9.313225746155E-10 0.000000000000E+00
    -1.141282763672E+04 8.685550689697E-01-0.000000000000E+00 1.000000000000E+00
    -2.281775537109E+04-4.101181030273E-01 1.862645149231E-09 0.000000000000E+00
R01 2020 01 03 02 45 00 5.505885928869E-05 0.000000000000E+00 4.410000000000E+05
     5.685046386719E+03 3.071467399597E+00-9.313225746155E-10 0.000000000000E+00
    -1.023803710938E+04 4.269771575928E-01 0.000000000000E+00 1.000000000000E+00
    -2.266500244141E+04 5.787792205811E-01 2.793967723846E-09 0.000000000000E+00
R01 2020 01 03 03 15 00 5.505979061127E-05 0.000000000000E+00 4.433700000000E+05
     1.105128369141E+04 2.841253280640E+00-0.000000000000E+00 0.000000000000E+00
    -9.878704101562E+03-1.961040496826E-02 9.313225746155E-10 1.000000000000E+00
    -2.076089892578E+04 1.523207664490E+00 1.862645149231E-09 0.000000000000E+00
R01 2020 01 03 03 45 00 5.506072193384E-05 0.000000000000E+00 4.446000000000E+05
     1.574637890625E+04 2.333828926086E+00 0.000000000000E+00 0.000000000000E+00
    -1.024903222656E+04-3.674869537354E-01 9.313225746155E-10 1.000000000000E+00
    -1.725210107422E+04 2.350193023682E+00 1.862645149231E-09 0.000000000000E+00

Best Answer

The link that Walter provided looks promising.
If you wish to pursue the processing on your own, here is a script that will read the GPS and GLONASS records into separate cell arrays.
You will have to add additional code where indicated to process each of the records that you read from your data file.
% ReadRINEX.m
fp = fopen("C:\Users\LesPC\Documents\MATLAB\Answers\shortenRNX.txt", 'rt');
% number of lines of data after the 'header' line
noLinesGPS = 7;
noLinesGLONASS = 3;
idxGPS = 1;
idxGLONASS = 1;
while true
    txtLine = fgetl(fp);
    if (txtLine == -1)
        break;
    end
    if (isempty(txtLine))
        break;
    end
    if (txtLine(1) == 'G')
        dataGPS{idxGPS} = txtLine; %#ok<SAGROW>

        for nLine = 1:noLinesGPS
            txtLine = fgetl(fp);
            dataGPS{idxGPS} = sprintf('%s %s', dataGPS{idxGPS}, txtLine);
        end
        idxGPS = idxGPS + 1;
    elseif (txtLine(1) == 'R')
        dataGLONASS{idxGLONASS} = txtLine; %#ok<SAGROW>
        for nLine = 1:noLinesGLONASS
            txtLine = fgetl(fp);
            dataGLONASS{idxGLONASS} = sprintf('%s %s', dataGLONASS{idxGLONASS}, txtLine);
        end
        idxGLONASS = idxGLONASS + 1;
    end
end
fclose(fp);
% Use sscanf or similar here to process the records that you read from the file
fprintf('%s:  Done\n', mfilename);
I've edited this because the for loops to read the lines after the 'header' were using the wrong value (idx... vs noLines...). Also, a better test for the end of the file.
Related Question