Modular automorphisms of the Drinfeld modular curves $X_0(\mathfrak{n})$

For $\mathfrak{n}\in\mathbb{F}_q[T]$, we determine the group of modular automorphisms of the Drinfeld modular curve $X_0(\mathfrak{n})$ or equivalently, the normalizer of the Hecke congruence subgroup $\Gamma_0(\mathfrak{n})$ in $GL_2(\mathbb{F}_q((T^{-1})))$. Some applications to the strong Weil uniformization of elliptic curves over $\mathbb{F}_q(T)$ are given.