  This paper proposes an algorithm to estimate the parameters, including time
delay, of continuous time systems based on instrumental variable identification
methods. To overcome the multiple local minima of the cost function associated
with the estimation of a time delay system, we utilise the useful redundancy
technique. Specifically, the cost function is filtered through a set of
low-pass filters to improve convexity with the useful redundancy technique
exploited to achieve convergence to the global minimum of the optimization
problem. Numerical examples are presented to demonstrate the effectiveness of
the proposed algorithm.
