Problem about gyro IDG300

Hi,

J’ve just learned to use the module IDG300 Breakout. I have some questions about its output rate: when I move, after some seconds, the output voltage is no longer correct, for example: at the beginning, when i don’t move, the output is 1.3 (all values are just for example. I don’t remember the exact values), but after 5 seconds, when I return to the first position and don’t move anymore, the output is 1.5. It means there’s an error value. My friend told me to recalibrate. But I have to save a long movement. So the value that I saved is not correct. Is anyone know how to fix this problem? Thank you.