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 Get ORBIT files from SOPAC or CDDIS archives  
  
 Usage: sh_get_orbits -archive <archive> -yr <yr> -doy <doy> -ndays <num> -multiday 
                      -type <type> -pre <f/r/p> -center <center> -makeg <yes/no> -maket -noacc 
                      -eop_ser <ser> -eop_pth <pth> -orbt <orbt> -ftp_prog <ftp/ncftp> 
  
 Where: <archive> Either sopac, cddis, or igscb  [Defautl sopac] 
        <yr> 4 char year of nav data requested  [Required] 
        <doy> 3 char day of year of nav data requested  [Required] 
        <num> Number of consecutive days of data to retreive  [Default 1] 
        <multiday> Form a multiday t-file from downloaded files 
        <type> Either sp3 or gfile (gfile from sopac only).  [Default sp3] 
        <f/r/p> The precision of the orbit requested.  [Default f] 
                  where f=final, r=rapid, p=predicted 
        <center> Name of the IGS processing center sp3 files. [Default igs] 
                 available centers igs/cod/emr/esa/gfz/jpl/ngs/sio 
        <makeg> Convert sp3 files in GAMIT format g-files files. [Default yes] 
        <noacc> Do not exclude satellites base on accuracy codes. [Default exclude]
        <ser> This is the pole. and ut1. series to be use when converting 
              sp3 -> g-files. ONLY use when makeg = yes. [Default bull_b] 
        <pth> This is the path to the pole.ser and ut1.ser files [Default ~/gg/tables] 
        <orbt> 4 char ID used in g-file name [Default 3 char center + 1 char pre. Ie igsf] 
        <ftp/ncftp> choose the ftp program to be used [default is ftp]
        makeg make a gamit g-file from downloaded SP3 file [default yes] 
        maket make a gamit t-file from downloaded SP3 file 
  
 NOTE: IGS sp3 files are available in f/r/p precision from both sopac and cddis archives 
       SIO sp3 files are available in   r/p precision ONLY from sopac archive 
       All other sp3 files are ONLY available in f precision form both cddis and sopac 
  
 Examples: sh_get_orbits -archive sopac -yr 1998 -doy 235 -ndays 1 -type gfile -pre r 
           sh_get_orbits -archive sopac -yr 1998 -doy 235 -ndays 1 -pre r -center sio 
           sh_get_orbits -archive cddis -yr 1998 -doy 235 -ndays 7 -ftp_prog ncftp
  
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