Let X(t), t ∈ R d be a centered Gaussian random field with continuous trajectories and set ξ u (t) = X(f (u)t), t ∈ R d with f some positive function. Classical results establish the tail asymptotics of P {Γ(ξ u ) > u}, T > 0 by requiring that f (u) tends to 0 as u → ∞ with speed controlled by the local behaviour of the correlation function of X. Recent research shows that for applications more general functionals than supremum should be considered and the Gaussian field can depend also on some additional parameter τ u ∈ K, say ξ u,τu (t), t ∈ R d . In this contribution we derive uniform approximations of P {Γ(ξ u,τu ) > u} with respect to τ u in some index set K u , as u → ∞. Our main result have important theoretical implications; two applications are already included in [12,13]. In this paper we present three additional ones, namely i) we derive uniform upper bounds for the probability of double-maxima, ii) we extend PiterbargPrisyazhnyuk theorem to some large classes of homogeneous functionals of centered Gaussian fields ξ u , and iii)we show the finiteness of generalized Piterbarg constants.