  Suppose that R is an ordered ring, G_n(R) is a subsemigroup of $GL_n(R)$,
consisting of all matrices with nonnegative elements. A.V. Mikhalev and M.A.
Shatalova described all automorphisms of G_n(R), where R is a linearly ordered
skewfield and n>1. E.I. Bunina and A.V. Mikhalev found all automorphisms of
G_n(R), if R is an arbitrary linearly ordered associative ring with 1/2, n>2.
In this paper we describe automorphisms of G_n(R), if R is a commutative
partially ordered ring, containing Q, n>2.
