Method for determining an air temperature with an ultrasonic sensor system, method for determining a distance with an ultrasonic sensor system and ultrasonic sensor system

A method for determining an output air temperature for an ultrasonic sensor system for a vehicle, comprising:

• (a) receiving an initial temperature value of an ambient air temperature of the ultrasonic sensor system having at least three ultrasonic sensors;
• (b) calculating a speed of sound based on the initial temperature value;
• (c) receiving sensor data of a corresponding ultrasonic signal emitted by the at least three ultrasonic sensors and reflected from at least one object;
• (d) determining a transit time for each ultrasonic sensor based on the corresponding ultrasonic signal;
• (e) calculating a reflection ellipse for each ultrasonic sensor based on the transit times and the calculated speed of sound, wherein the reflection ellipses describe possible positions of the at least one object reflected by the corresponding ultrasonic signal in a direction of a respective ultrasonic sensor of the at least three ultrasonic sensors;
• (f) determining intersection points, tangential lines, and/or tangential planes between the reflection ellipses;
• (g) when there is a common intersection point, a common tangential line, and/or a common tangential plane between all reflection ellipses, identifying the initial temperature value as the output air temperature;
• and
• (h) when there is no common intersection point, no common tangential line, and/or no common tangential plane between all reflection ellipses, (i) varying size parameters of the reflection ellipses until an adjusted common intersection point, an adjusted common tangential line, and/or an adjusted common tangential plane exists between all reflection ellipses;
• and (ii) calculating a calculated temperature value for the reflection ellipses with the adjusted common intersection point, the adjusted common tangential line, and/or the adjusted common tangential plane, and identifying the calculated temperature value as the output air temperature.