A method for determining at least one physical parameter of a system comprising at least two reflection objects is presented, comprising: producing a transmission signal comprising at least one modulated electromagnetic or acoustic wave; receiving a first reception signal that is based on the transmission signal reflected by a first reflection object; receiving a second reception signal that is based on the transmission signal reflected by a second reflection object; receiving a third or further reception signal(s) that is/are based on the transmission signal reflected by a first or second or further reflection object(s); ascertaining the at least one physical parameter of the system on the basis of the first reception signal and further reception signals; ascertaining unknown distances between reflection objects or material properties, composition or nature of the media between the reflection objects of the system on the basis of the first reception signal and further reception signals.