| 摘要 |
For the purpose of accurate determination of the velocity component (vH, vL) in the horizontal and vertical direction independently of the velocity of sound, this Doppler log exhibits a transmitting and receiving device (12) for sending out wave energy and for receiving the reflected wave energy from two selective directions of reception (A, V), inclined to the transducer plane (14) and located symmetrically with respect to the normal of the transducer plane (14), and from a third selective direction of reception (O) coinciding with the normal. The directions of reception (A, O, V) are adjusted by suitably shifting the phase ( phi ) of the received signals of the individual transducers (15). The Doppler frequency (fA, fO, fV) is determined from each direction of reception (A, O, V). From the Doppler frequencies (fA, fV) of the inclined symmetrical directions of reception, the Doppler difference ( DELTA f) which is a measure of the velocity along the longitudinal axis (16) of the vehicle is determined, on the one hand, and, on the other hand, the Doppler sum ( SIGMA f) is determined. A processor (27) calculates from the Doppler sum ( SIGMA f) and the Doppler frequency (fO) from the third direction of reception (O) a velocity term (T) which is logically combined with the Doppler difference ( DELTA f) and the elevation angle ( epsilon ) for determining the accurate horizontal and vertical components (vH, vL) of the vehicle velocity. <IMAGE>
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