Since saturation often plays an important role in limiting the performance of guidance loops, performance analysis of guidance loops with saturation has been a popular subject of investigation. Most work so far has concentrated on the effect of saturation on stochastic performance of guidance loops, using as an essential tool stochastic linearization methods. However, saturation limits performance also against in the deterministic case. This paper proposes a systematic approach to determine the influence of saturation on the performance of a guidance loop in the case of deterministic exogenous signals. The primary ingredient of the proposed approach is a numerical procedure to estimate time-varying upper-bounds for the input to the saturation element. © 2011 by TNO, The Netherlands and DSTO, Australia.