ADIS16203: Relative accuracy explanation

Q

What does "relative accuracy" mean? (for ADIS16203) & how measured?

A

Relative accuracy (same as INL or Integral Nonlinearity for a data converter)
refers to the worst case inaccuracy of the device transfer curve (usually being
the worst case deviation from a straight connecting the upper and lower
endpoints).

If we draw a perfect line (horizontal axis = actual incline angle, vertical
axis = measured incline angle), the worst-case deviation from this line will
equal to the relative accuracy specification. What sort of accuracy are you
looking for ?
FYI, there is an auto null feature that is there to help with managing
post-installation errors as well.