function [FL1,FL2,GPRN] = get_sat_freq(sat)
GPRN     = str2double(sat(2:end));
switch sat(1)
    case {'G','GPS'}
        FL1         = 1.57542E9;
        FL2         = 1.22760E9;
    case {'R','GLONASS'}
        Kfrq        = [1,-4,5,6,1,-4,5,6,-2,-7,0,-1,-2,-7,0,-1,4,-3,3,2,4,-3,3,2];
        baseFL1     = 1.602E9;
        baseFL2     = 1.246E9; 
        DFRQ1_GLO   = 5.625E5;
        DFRQ2_GLO   = 4.375E5;
        FL1         = baseFL1+Kfrq(GPRN)*DFRQ1_GLO;
        FL2         = baseFL2+Kfrq(GPRN)*DFRQ2_GLO;
        GPRN        = GPRN+100;
    case {'E','GALILEO'}
        FL1         = 1.57542E9; % Note the Galeo for SPIRE uses E1 as L1, and L7Q (E5b) as L2. 
        FL2         = 1.20714E9;
        GPRN        = GPRN+200;
    case {'C','BEIDOU'}
        FL1         = 1.57542E9;
        FL2         = 1.17645E9;
        GPRN        = GPRN+400;
    otherwise
        error('Non GREC gnss sat id: %s\n',sat)
end
