Convert TRRM Real Time Binary File into ESRI ASCII

Seven simple steps for converting TRMM binary to ASCII grid using MATLAB

Step1:

 %Open TRMM realtime binary file

trmmFile = fopen('E:\TrmmBinary Processing\3B42RT.2012.03.27.09z.bin', 'rb');  

Step2:

%Move file pointer to the begining of  file

frewind(trmmFile);

Step3:

%Read TRMM value from the binary file having 1140 rows and 480 columns

precipitation = fread(trmmFile, [1440,480], 'float32','b');

Step4:

%Shift precipitation by 90 degree to relate data with equator

precipitation = rot90(precipitation);

 Step5:

%Assign ESRI ASCII GRID HEADER

%After rotaion by 90 degree ncols changed into 1440 from 480 and nrows

%changed into 480 from 1440

 Step6:

%Open ASCII file to store binary data

asciiFile='3B42RT.2012.03.27.09z.bin_matlab.asc';

Step7:

%Write ASCII header for ESRI ASCII

header0='ncols 1440';

header1='nrows 480';

header2='xllcorner 0';

header3='yllcorner -60';

header4='cellsize 0.25';

header5='NODATA_value -99999';

dlmwrite(asciiFile, header0,'delimiter','','newline','pc');

dlmwrite(asciiFile, header1,'delimiter','','newline','pc','-append');

dlmwrite(asciiFile, header2,'delimiter','','newline','pc','-append');

dlmwrite(asciiFile, header3,'delimiter','','newline','pc','-append');

dlmwrite(asciiFile, header4,'delimiter','','newline','pc','-append');

dlmwrite(asciiFile, header5,'delimiter','','newline','pc','-append');

dlmwrite(asciiFile, precipitation,'delimiter',' ','precision',6,'roffset',0,'coffset',0,'-append');

Addition: Read TRMM RT binary and convert it into X-Coordinate,Y-Coordinate,Z-value table into a CSV file 

Open binary file
fid = fopen('E:\TrmmBinary Processing\3B42RT.2012.03.02.03z.bin', 'r');
Move file reader into the begining of the file
frewind(fid);
Read 32bit floating point binary with 1440 row/lat and 480 cols/lat
precipitation = fread(fid, [1440,480], 'float32','b');
precipitation = rot90(precipitation);
lon=1440;
lat=480;
for lo=1:lon
    for la=1:lat
        rlon=0.125+0.25*(lo-1);
        rlat=-59.875+0.25+(la-1);
        output=sprintf('f,f,f',rlat,rlon,precipitation(lo,la));
        disp(output);
        M=[rlat,rlon,precipitation(lo,la)];
        dlmwrite ('trmmoutput.csv',M,'-append');

   end
  end
Enjoy

References:

MATLAB Codes: http://disc.sci.gsfc.nasa.gov/additional/faq/precipitation_faq.shtml#ENVI

More docs: ftp://meso.gsfc.nasa.gov/pub/trmmdocs/rt/

ASCII , MATLAB