Compass is a software product for the modelling of electro-optical sensors, and is commercially available.  It has been designed to be versatile, flexible and easy to use, aimed at the electro-optic sensors specialist, who will be familiar with the language of electro-optics and concepts such as MTF, PSF, NEI, NETD, MRTD and D*.  It can provide great benefit to users who want to reconfigure the software quickly to support their requirements, that do not wish to devote a great deal of time to computer programming, and who are not necessarily specialist computer programmers.  It will satisfy the needs of the analyst as a simple point-and-click application to carry out tasks such as applying sensor effects to imagery, as well as developer for building and testing new sensor models or for modifying existing ones.