Removing ambiguities within a single stage becomes crucial when one can not
use multiple detectors behind each other to resolve them which naturally is the
case for neutral radiation. An example would be RICH detectors. Commonly
pixilated readout is choosen for this purpose. However, this causes a
remarkable increase in quantity of channels and does not scale up well.
Therefore, the XYU-GEM was proposed as a three coordinate strip-readout which
is combined with a triple GEM detector. The readout complements a common XY
readout with an additional projection which is tilted by 45{\deg}. The
overdetermination due to three projections can be used to resovle ambiguities.
Following the detector design will be explained, first measurements discussed
to understand the response of the detector and a way to change the charge
sharing without changing the manufacturing parameters of the readout