We consider the gamma process perturbed by a Brownian motion (independent of
the gamma process) as a degradation model. Parameters estimation is studied
here. We assume that $n$ independent items are observed at irregular instants.
From these observations, we estimate the parameters using the moments method.
Then, we study the asymptotic properties of the estimators. Furthermore we
derive some particular cases of items observed at regular or non-regular
instants. Finally, some numerical simulations and two real data applications
are provided to illustrate our method.