I see that your link (good examples by the way) says that it actual uses the linear acceleration of the "vehicle" to make its references.
Is this a new adaptation of accelerometers or what my research really just taking me in the wrong direction because until now I was reading that if I wanted to be traveling along the hill that the accelerations associated with the linear motion of the vehicle would cause the accelerometer to have errors?
Also would you suggest any specific models or accelerometers I have been looking at the following; ADXL3335, MXR7250VW, MXR7305, MXC6232XMP, AIS328DQTR, SCA3100-D04, as well as looking at the combination models such as MPU-6050, Phidget Spatial 3/3/3, and ASC-IMU 7-LN.