US 12,436,277 B2
Method for elevation angle estimation based on an ultrasound sensor
Wassim Suleiman, Frankfurt (DE); Christopher Brown, Seligenstadt (DE); and Robin Adams, Frankfurt am Main (DE)
Assigned to Continental Autonomous Mobility Germany GmbH, Ingolstadt (DE)
Appl. No. 17/753,669
Filed by Continental Automotive GmbH, Hannover (DE)
PCT Filed Aug. 31, 2020, PCT No. PCT/EP2020/074176
§ 371(c)(1), (2) Date Mar. 10, 2022,
PCT Pub. No. WO2021/047927, PCT Pub. Date Mar. 18, 2021.
Claims priority of application No. 19196984 (EP), filed on Sep. 12, 2019.
Prior Publication US 2022/0334250 A1, Oct. 20, 2022
Int. Cl. G01S 15/89 (2006.01); G01S 7/52 (2006.01); G01S 15/58 (2006.01); G01S 15/60 (2006.01)
CPC G01S 15/89 (2013.01) [G01S 7/5202 (2013.01); G01S 7/52025 (2013.01); G01S 15/582 (2013.01); G01S 15/60 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method for determining the elevation angle of a signal received by an ultrasound sensor, the method comprising:
providing an ultrasound sensor with a frequency-dependent radiation pattern;
transmitting, by the ultrasound sensor, at least a first ultrasound wave at a first frequency;
transmitting, by the ultrasound sensor, at least a second ultrasound wave at a second frequency different from the first frequency;
receiving, by the ultrasound sensor, reflections of the first and second ultrasound waves, the reflections being caused by a certain object;
determining the elevation angle of the first and second reflected ultrasound waves based on amplitudes of the reflections of the first and second ultrasound waves;
wherein determining the elevation angle is performed by calculating a ratio between the amplitudes of the reflections of the 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 calculated ratio, and
wherein the ambiguities of the radiation pattern in the vertical direction are removed by using at least one ultrasound sensor providing an asymmetric radiation pattern in the vertical direction, 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 by removing the first elevation angle based up 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.