| 摘要 |
<p>A method and system for ultrasonic locationing using time difference of arrival measurements includes an ultrasonic receiver including three microphones (116) each disposed on a periphery of a housing and a fourth centrally-positioned microphone (216). A controller establishes only time difference of arrival measurements of an ultrasonic signal at each microphone, assumes an arbitrary flight time for the signal in order to obtain three flight distances (Rl, R2, R3) of the signal at each of the three microphones, calculates an intersection point (206) of three spheres having radii equal to the three flight distances, calculates a distance from the intersection point to the central microphone, subtracts the distance from a sum of the arbitrary flight time plus the time difference of arrival measurement for the central microphone to establish an test error, and searches different arbitrary flight times along a straight line (200) through the central microphone and intersection point until the test error is less than a threshold, indicating an actual location (106) of the emitter.</p> |
