Abstract: The invention relates to a method for operating an ultrasonic sensor device (2) for monitoring an underbody region (12) of a motor vehicle (1), wherein ultrasonic signals (U) are emitted into the underbody region (12) by means of at least one ultrasonic sensor (4, 5, 6, 7) of the ultrasonic sensor device (2), and the reflected ultrasonic signals (U) are received and analyzed. After the motor vehicle (1) is parked at a first point in time (t1), a reference measurement curve (13) for the underbody region (12) is generated on the basis of at least one ultrasonic signal (U) and is stored, wherein a measurement region (18) is determined in the reference measurement curve (13) in which the monitoring process of the underbody region (12) is analyzed, and the measurement region (18) is determined on the basis of the decay time (16) of the ultrasonic sensor (4, 5, 6, 7) and a ground reflection (19) on the ground surface (11).

Abstract: A method for monitoring a ground clearance beneath a motor vehicle is disclosed. On the underbody of the motor vehicle, a plurality of ultrasonic transceivers are arranged spaced apart from one another. The method includes sending a transmission signal from a first ultrasonic transceiver, receiving a reflected transmission signal with a second ultrasonic transceiver, repeating the sending and receiving steps, determining a profile of a ground beneath the vehicle based on the echo signals, and determining a minimum ground clearance by comparing the ground profile with the underbody profile of the motor vehicle. Different pairs consisting of a first and a second ultrasonic transceiver are selected to receive a respective echo signal.

Abstract: A method and an analysis system for determining a state of a diaphragm of an ultrasound sensor during operation is disclosed. The diaphragm of the ultrasound sensor is excited with a first excitation signal in a predefined first frequency profile. Based on this, a first voltage profile, which depends on a frequency of the first excitation signal, is measured. Analogously, a second voltage profile is determined by applying a second excitation signal to the diaphragm and then carrying out a measurement. These two voltage profiles are shifted so that respective positions of maxima of the two voltage profiles are matched to each other in a predefined frequency range. A third voltage profile, which runs between the shifted first and second voltage profiles, is determined. Based on the third voltage profile, electrical parameters are determined by a model for continuous excitation of the diaphragm to determine the state of the diaphragm.

Abstract: The invention relates to a method for operating an ultrasonic sensor device (2) for monitoring an underbody region (12) of a motor vehicle (1), wherein ultrasonic signals (U) are emitted into the underbody region (12) by means of at least one ultrasonic sensor (4, 5, 6, 7) of the ultrasonic sensor device (2), and the reflected ultrasonic signals (U) are received and analyzed. After the motor vehicle (1) is parked at a first point in time (t1), a reference measurement curve (13) for the underbody region (12) is generated on the basis of at least one ultrasonic signal (U) and is stored, wherein a measurement region (18) is determined in the reference measurement curve (13) in which the monitoring process of the underbody region (12) is analyzed, and the measurement region (18) is determined on the basis of the decay time (16) of the ultrasonic sensor (4, 5, 6, 7) and a ground reflection (19) on the ground surface (11).

Abstract: A method and an analysis system for determining a state of a diaphragm of an ultrasound sensor during operation is disclosed. The diaphragm of the ultrasound sensor is excited with a first excitation signal in a predefined first frequency profile. Based on this, a first voltage profile, which depends on a frequency of the first excitation signal, is measured. Analogously, a second voltage profile is determined by applying a second excitation signal to the diaphragm and then carrying out a measurement. These two voltage profiles are shifted so that respective positions of maxima of the two voltage profiles are matched to one another in a predefined frequency range. A third voltage profile, which runs between the shifted first and second voltage profiles, is determined. Based on the third voltage profile, electrical parameters are determined by a model for continuous excitation of the diaphragm to determine the state of the diaphragm.

Abstract: A method serves for imaging polarimetry. A chipless, passive transponder which has a plurality of surface regions with different polarimetric properties is illuminated fully polarimetrically by radar radiation. At least one polarization-encoded image of the transponder is generated using the radar radiation reflected thereby, and the different surface regions of the transponder in the polarization-encoded image can be recognized by their at least one polarimetric property. The passive, chipless transponder has at least two surface regions with different polarimetric structures.

Abstract: A method serves for imaging polarimetry. A chipless, passive transponder which has a plurality of surface regions with different polarimetric properties is illuminated fully polarimetrically by radar radiation. At least one polarization-encoded image of the transponder is generated using the radar radiation reflected thereby, and the different surface regions of the transponder in the polarization-encoded image can be recognized by their at least one polarimetric property. The passive, chipless transponder has at least two surface regions with different polarimetric structures.