The invention relates to a tracking reference, comprising: a reference array (1) featuring a positionally fixed arrangement of at least two tracking markers (3); and an interface (4A) for detachably coupling the reference array (1) to a base member (2), wherein the interface (4A) comprises at least one supporting surface (5) for contacting the base member (2), wherein the interface (4A) comprises magnetic means (6) which generate a force at the reference array, wherein the force (F) is directed away from the supporting surface (5).