声学多普勒测速仪标校技术研究

为了提高声学多普勒测速仪输出速度的准确度,安装过程中测速基阵与载体之间的偏差角不可忽略,安装偏差角包括航向偏角,横摇角及纵摇角三类。介绍了一种三维空间上的多普勒标定技术,通过高精度的GPS导航仪以及多普勒测速仪对海底测速,利用速度比值差校准航偏角。通过纵向剖面的几何关系,从航偏角出发进而获得纵摇角和横摇角的大小,完成了三维方向上多普勒测速仪的校准,使多普勒测速仪坐标系与载体坐标系能够进行精确转换,从而提高了声学多普勒测速仪输出速度的准确度。外场试验较好地证明了该方法的有效性,分析结论看出在二维平面上,造成误差的原因主要在于安装偏角的航向偏角,而在三维空间上,尤其垂向速度,误差主要由纵摇角和横摇角产生。该方法可以快速地对三维安装偏角进行校准,运算量小,并且在对海水测速后续研究中可以形成一套体系。

Study on the calibration method of acoustic Doppler velocimeter

In order to improve the accuracy of acoustic Doppler velocimeter, the deviation angles between the velocity transducer and the carrier in the process of installation can not be ignored. The deviation angles include yaw angle, roll angle and pitch angle. A calibration method in three dimensional space is proposed in this paper. By using high-precision GPS navigator and Doppler velocimeter to measure bottom velocity, the yaw angle can be calibrated in terms of the velocity ratio. Then, by the geometric relationship of longitudinal profile, the magnitudes of pitch angle and roll angle are obtained from the yaw angle. Thus, the calibration of the 3D directional Doppler velocimeter is completed and the Doppler velocimetry coordinates and the carrier vector coordinates can be transformed accurately, which makes the accuracy of acoustic Doppler velocimeter improved. The effectiveness of this method is proved in field tests. The analysis results show that the main error of velocity measurement in two dimensional plane is caused by yaw angle, however, in three dimensional space, particularly for measuring vertical velocity, the error is mainly caused by roll angle and pitch angle.