| 摘要 |
An ultrasonic airspeed and direction sensors comprises at least four ultrasonic sensors 3 arranged to define at least four bidirectional ultrasonic paths 20/21 that form at least three non coplanar sets. The time of flight of the paths is measured and a weighted selection of at least one path 20/21 out of each non coplanar set is made; the weighted data is used to determine the wind speed and direction information. The ultrasonic airspeed and direction sensor is suitable for mounting to a vehicle such as an aircraft or helicopter. The ultrasonic system may comprise at least four non coplanar sets or six ultrasonic paths 20/21 forming three non coplanar sets of two parallel paths 20/21. The weighting system may be calculated using a Least Squares fit algorithm judged against previous readings, or from the amplitude of the received ultrasonic signals. |
