System and method for observing the presence, location, movement and/or attitude of one or more objects to be monitored with a monitoring system, wherein sensors of the system are disposed in a part, such as on a floor, wall or ceiling, of the area to be monitored, and the system measures with sensors the area to be monitored, and determines the presence, location, movement and/or attitude of the object on the basis of the measurement results of the sensors. The system has a first mode and a second mode, and the system checks in the first mode the attitude and/or state of health of the object in the area to be monitored and functions in the second mode as an intruder alarm monitoring the area to be monitored.