For my bachelor’s graduation project, I did an internship at TNO, working on a project for the Ministry of Defence. This thesis describes and discusses the project that looked for a prediction model for the magnetic background field on a naval ship. The prediction model that was developed during this project separates the magnetic background field from other existing, observed magnetic fields. Determination of the magnetic background field on naval ships helps the reduction of detection risk. Further research and fine tuning of this model might be of use to The Royal Dutch Navy in order to avoid any risk of detonation of naval mines in threat areas.