Method for elevation angle estimation based on an ultrasound sensor

A driving assistance system comprising at least one ultrasound sensor having a frequency-dependent radiation pattern and a controller for controlling a provision of ultrasound signals to the ultrasound sensor, the controller being configured to:

• initiate transmission of at least a first ultrasound wave at a first frequency;
• initiate transmission of at least a second ultrasound wave at a second frequency different from the first frequency;
• receive information regarding reflections of the first and second ultrasound waves, the reflections being caused by a certain object;
• determine an elevation angle of the first and second reflected ultrasound waves based on amplitudes of the reflections of the first and second ultrasound waves;
• wherein the elevation angle is determined by calculating a ratio between the amplitudes of received reflections of first and second ultrasound waves and mapping the calculated ratio to an elevation angle, wherein the mapping is performed based on a predetermined ratio curve or ratio dataset which associates a certain amplitude ratio to a corresponding elevation angle,
• wherein determining the elevation angle comprises removing ambiguities of the radiation pattern in a vertical direction, the ambiguities comprising a plurality of elevation angles corresponding to the certain object, and
• wherein the radiation pattern is divided into an upper half-space portion and a lower-half-space portion with a horizontal plane separating the upper half-space portion and the lower half-space portion, the plurality of elevation angles corresponding to the calculated ratio comprises a first elevation angle in the upper half-space portion and a second elevation angle in the lower half-space portion, and the ambiguities of the radiation pattern in the vertical direction are removed based upon an assumption that a detected object is arranged in the lower half-space portion such that the ambiguity associated with the first elevation angle is removed.

A driving assistance system comprising at least one ultrasound sensor having a frequency-dependent radiation pattern, the driving assistance system being configured to:

• initiate transmission of at least a first ultrasound wave at a first frequency;
• initiate transmission of at least a second ultrasound wave at a second frequency different from the first frequency;
• receive information regarding reflections of the first and second ultrasound waves, the reflections being caused by a certain object;
• determine the elevation angle of the first and second reflected ultrasound waves based on the amplitudes of the reflections of the first and second ultrasound waves;
• wherein the elevation angle is determined by calculating a ratio between the amplitudes of received reflections of first and second ultrasound waves and mapping the calculated ratio to an elevation angle, wherein the mapping is performed based on a predetermined ratio curve or ratio dataset which associates a certain amplitude ratio to a corresponding elevation angle,
• wherein determining the elevation angle comprises removing ambiguities of the radiation pattern in a vertical direction, the ambiguities comprising a plurality of elevation angles corresponding to the certain object, and
• wherein the radiation pattern is divided into an upper half-space portion and a lower-half-space portion with a horizontal plane separating the upper half-space portion and the lower half-space portion, the plurality of elevation angles corresponding to the calculated ratio comprises a first elevation angle in the upper half-space portion and a second elevation angle in the lower half-space portion, and the ambiguities of the radiation pattern in the vertical direction are removed based upon an assumption that a detected object is arranged in the lower half-space portion such that the ambiguity associated with the first elevation angle is removed.