If permanently installed systems are to be deployed widely, it is vital that the data is high quality and processed so that false calls are avoided, and it is presented to operators in a form that enables skilled operator attention to be focused on the areas where action is needed. This requires research on the causes of drift in readings and means of compensating for them. Automatic change detection algorithms will be required that optimise the probability of detection (POD)/false call trade-off without requiring intervention by skilled operators; this is a significant area of research and will have applications across a range of monitoring methodologies.