Introduction

Apart from a few simple cases such as an interferometer with pointlike apertures (see e.g. [6,7]) or an interferometer with ideal AO correction (e.g. [8,9]), the only approach which can be used to analyse the temporal properties of interferometric fringes is that of numerical simulation. Numerical simulations are also required to investigate specialised components in interferometers such as spatial filters (e.g. [5]). For this reason, numerical studies have often played an important role in studies of interferometer performance or design (e.g. [6]).

Numerical simulations were required in the preliminary stages of the error budget preparation for PRIMA in order to obtain order-of-magnitude estimates for many of the complicated error terms and highlight those which might be problematic. In order to minimise the time invested, existing atmospheric simulations were used with the minimum modification required for useful estimates of terms in the PRIMA error budget. More realistic simulations may be required at a later date to study in detail error terms which are expected to have a significant impact on the overall performance of PRIMA.