I am working on the project where I wnat to measure the inclination of a vehicle. For this I have selected digital inclinometer and MEMS accelerometer ADIS 16209. It gives accurate tilt angle in static (rest motion) condition. But as it is unable to distinguish betwen acceleration due to gravity and acc due to linear motion, in dynamic condition (when vehicle is moving) the motion affects the angle producing inaccurate tilt angle. To overcome this I have also incorporated MEMS gyroscope ADIS 16251, whose integrated angle output is independent of linear motion, as it only responds to rotation. But again the gyroscope always gives some error in terms of rotation rate even though it is at rest (no rotation) condition. This small error eventually adds up and produces big error in angle measuement over the periode of time. Although there are facilities like Autonull or Factory restore,there is considerable error observed. So how can I used both Accelerometer and Gyroscope to estimate accurate tilt angle in dynamic condition?