struct StructBuff_t {
char GPS[100];
char imuRoll[6];
char imuPitch[6];
char imuYaw[6];
char AP[3];
char SenBuffersAll[128];
}
StructBuff;
This is STILL wrong. Until you fix it, I can't help you.
You either store the GPS data as character data and the other stuff as floats (or strings) in the struct, OR you store all the data in and array.
What you have now is a box of stuff to send. Then, you make a copy of the stuff to send, and put the copy in an envelope. Then, you throw the envelope in the box, and send the box. That hardly makes sense.