Hello Sankar Das,

Interfacing a 8051 to a GPS receiver is pretty easy. Most GPS receivers output multiple NEMA sentences such as the following at 4800 baud (8N1) in RS232 serial format.

$GPGGA,,,,,,0,00,,,,,,,*66
$GPGSA,,,,,,*42
$GPRMC,000136,V,3648.4448,S,17444.5042,E,0.000,0.0,290697,19.5,E*42
$PRWIZCH,23,0,23,0,23,0,23,0,23,0,23,0,23,0,23,0,24,0,23,0,24,0,23,0*4D
$GPGGA,,,,,,0,00,,,,,,,*66
$GPGSA,,,,,,*42
$GPRMC,000137,V,3648.4448,S,17444.5042,E,0.000,0.0,290697,19.5,E*43
$PRWIZCH,23,0,23,0,23,0,23,0,23,0,23,0,24,0,24,0,24,0,23,0,24,0,23,0*4D
$GPGGA,,,,,,0,00,,,,,,,*66
$GPGSA,,,,,,*42
$GPRMC,000138,V,3648.4448,S,17444.5042,E,0.000,0.0,290697,19.5,E*4C
$PRWIZCH,23,0,23,0,23,0,23,0,23,0,23,0,24,0,24,0,24,0,23,0,24,0,23,0*4D
$GPGGA,,,,,,0,00,,,,,,,*66

Now you are one interested in one of these protocols you have to write software which only capture one of these such as the following

$GPRMC,235947,V,3714.6284,N,12146.9181,W,0.000,0.0,280697,15.4,E*47
$GPRMC,235947,V,3714.6284,N,12146.9181,W,0.000,0.0,280697,15.4,E*47
$GPRMC,235947,V,3714.6284,N,12146.9181,W,0.000,0.0,280697,15.4,E*47
$GPRMC,235947,V,3714.6284,N,12146.9181,W,0.000,0.0,280697,15.4,E*47
$GPRMC,235947,V,3714.6284,N,12146.9181,W,0.000,0.0,280697,15.4,E*47
$GPRMC,235947,V,3714.6284,N,12146.9181,W,0.000,0.0,280697,15.4,E*47
$GPRMC,235947,V,3714.6284,N,12146.9181,W,0.000,0.0,280697,15.4,E*47
$GPRMC,235947,V,3714.6284,N,12146.9181,W,0.000,0.0,280697,15.4,E*47
$GPRMC,235947,V,3714.6284,N,12146.9181,W,0.000,0.0,280697,15.4,E*47

The software to do this is not difficult to write and BASECOM could do the job. Simply write code that starts looking for a $GPRMC (or whatever protocol you are using) and once is has found it simply capture the data into a buffer until a carriage return is detected (0x13 or 0x10).

Once you have the data filtered it is pretty simple to extract the fields you are interested in.

Regards,

Charles Bannister