Abstract: A method of monitoring access authorizations by an access monitoring system by a first method, the data carriers or the mobile electronic devices, on which a valid access authorization or an ID is assigned, are detected and the carriers/devices current positions are determined by trilateration or multilateration. A second imaging method is executed, parallel to the first method, and the current position of all persons presented in the entry area is detected by cameras. All persons, with and without valid access authorization, in the entry area are detected so that an ID map and a people map are created. The ID map corresponds to people who have valid access authorization and the people map corresponds everybody in the entry area. An overlay map is created by matching the ID map with the people map, to identify persons with valid access authorization or ID and the people without valid access authorization.