I. Introduction
In this paper we investigate the exact observability of port-Hamiltonian systems of the form \begin{align*}& \frac{{\partial x}}{{\partial t}}(\zeta ,t) = \left({{P_1}\frac{\partial }{{\partial \zeta }} + {G_0}}\right)({\mathcal{H}}(\zeta )x(\zeta ,t)), \\ & x(\zeta ,0) = {x_0}(\zeta ), \\ & 0 = \left[ {{W_{B,1}}\quad {W_{B,0}}} \right]\left[ {\begin{array}{c} {({\mathcal{H}}x)(1,t)} \\ {({\mathcal{H}}x)(0,t)} \end{array}} \right], \\ & y(t) = \left[ {{W_{C,1}}\quad {W_{C,0}}} \right]\left[ {\begin{array}{c} {({\mathcal{H}}x)(1,t)} \\ {({\mathcal{H}}x)(0,t)} \end{array}} \right],\end{align*} where ζ ∈ [0, 1] and t ≥ 0. We refer to Section III for the precise assumptions on P1, G0, [WB,1 WB,0], [WC,1 WC,0] and .