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 air temperature for an ultrasonic sensor system, in particular for a vehicle, is disclosed. The method includes determining the intersection points and/or tangential lines and/or tangential planes between the reflection ellipses. If there is a common intersection point and/or a common tangential line and/or a common tangential plane between all reflection ellipses, then identifying the output temperature value as the current air temperature. If there is no common intersection point and/or no common tangential line and/or no common tangential plane between all reflection ellipses, then (i) varying size parameters of the reflection ellipses until a common intersection point and/or a common tangential line and/or a common tangential plane exists between all reflection ellipses, and (ii) calculating a temperature value for the reflection ellipses with a common intersection point and/or a common tangential straight line and/or a common tangential plane and identifying the temperature value as the current air temperature.
1 . 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.
2 . The method according to claim 1 , wherein calculating the calculated temperature value comprises:
(i) calculating an adjusted speed of sound for the reflection ellipses based on the transit times of the ultrasonic signals and travel distances of the ultrasonic signals based on the varied size parameters of the reflection ellipses; and
(j) calculating the calculated temperature value based on the adjusted speed of sound.
3 . The method according to claim 2 , wherein steps (c) to (j) are repeated for configurations in which each of the at least three ultrasonic sensors acts as a transmitting ultrasonic sensor configured to transmit the corresponding ultrasonic signal while two other ultrasonic sensors act only as receivers of the corresponding ultrasonic signal.
4 . The method according to claim 3 , wherein the steps (c) to (j) are carried out for an additional fourth ultrasonic sensor.
5 . The method according to claim 3 , wherein:
the reflection ellipse of the transmitting ultrasonic sensor is a circle, and
the reflection ellipses of the two other ultrasonic sensors are configured such that the two other ultrasonic sensors and the transmitting ultrasonic sensor are arranged at focal points of the reflection ellipse.
6 . The method according to claim 1 , wherein the initial temperature value is a measured value of a temperature sensor.
7 . The method according to claim 1 , wherein:
the method is carried out cyclically, and
the initial temperature value corresponds to the output air temperature determined in a preceding execution cycle.
8 . The method according to claim 1 , wherein the size parameters of the reflection ellipses comprise small half-axes and large half-axes of the reflection ellipses.
9 . A method for determining distance using an ultrasonic sensor system, comprising:
carrying out a method, according to claim 1 , for determining an output air temperature for the ultrasonic sensor system and determining the output air temperature; and
determining a distance of another object from the ultrasonic sensor system based on (i) a transit time of a corresponding ultrasonic signal for each ultrasonic sensor of the ultrasonic sensor system, and (ii) the output air temperature.
10 . The method according to claim 9 , wherein a data processing unit is configured to carry out the method for determining distance using the ultrasonic sensor system.
11 . A calculating unit configured to carry out a method, according to claim 1 , for determining an output air temperature for an ultrasonic sensor system for a vehicle.
12 . The method according to claim 1 , wherein a data processing unit is configured to carry out the method for determining the output air temperature for the ultrasonic sensor system for the vehicle.
13 . An ultrasonic sensor system, comprising:
at least three ultrasonic sensors, and
a calculating unit according to claim 11 .
14 . A calculating unit configured to carry out a method, according to claim 9 , for determining distance using an ultrasonic sensor system.
15 . An ultrasonic sensor system, comprising:
at least three ultrasonic sensors, and
a calculating unit according to claim 14 .