I found a variety of gyros that are suitable for my application but i have trouble understanding that when it is mentioned in the spec. of certain model, that it can measure the yaw and pitch or roll and pitch , or x-y plane , what are the reference to the axes ,is it the earth?
i beleive it makes more sense that the reference is the plane of the gyro’s board.
i hope that someone helps me out , i will appretiate it 
Yes the reference is to the Gyro chip itself or to the board it is mounted on. The data sheet should have a diagram showing the chip reference to the mentioned axises.
ok so the angle i am measuring is for a rotating rod that is held in an inclined manner referrenced to the earth , in this case does the gyro work properly or i need to calibrate it , and if yes does the same go for an accelerometer ,
i should have been more specific in the first post but i forgot that i am going to need this info too :?