重力感应、陀螺仪相关算法

rx,ry,rz为弧度值，x,y,z为重力感应值；
rx = atan(x / sqrt(yy + zz)) 180/3.1415926
ry = atan(y / sqrt(xx + zz)) 180/3.1415926
rz = atan(z / sqrt(xx + yy)) *180/3.1415926