if(strstr(buf, "$GPRMC")){
float time = 0;
char valid = 0;
float latitude = 0;
char NorthSouth = 0;
float longtitude = 0;
char EastWest = 0;
float sog = 0;
float direction = 0;
int date = 0;
float magneticDeclination = 0;
char magneticEastWest = 0;
int checkSum = 0;

sscanf(buf, "$GPRMC,%f,%c,%f,%c,%f,%c,%f,%f,%d,%f,%c*%x",
&time,
&valid,
&latitude,
&NorthSouth,
&longtitude,
&EastWest,
&sog,
&direction,
&date,
&magneticDeclination,
&magneticEastWest,
&checkSum);
}
これでOK？　上手く動かないんだけどな。。