基于MEMS加速度计空投浮标的波浪测量方法试验研究

针对基于MEMS加速度传感器的空投波浪浮标存在采样频率与测波精度低的问题，根据频域衰减积分算法，提出一种相应的波浪测量算法，为了验证该算法测波的准确性，开展了多功能水槽试验研究。该算法旨在将MEMS加速度传感器输出的加速度与姿态角转化为浮标运动的波形，首先将加速度与姿态角信号进行竖向处理获得竖直方向的加速度，再利用离散傅里叶变换将竖向加速度转化为频域内的加速度复数序列，然后引入控制函数减弱低频噪声，经过频域积分、离散傅里叶逆变换、时域积分获得竖直方向的位移，最后通过后处理得到最终的波形。多功能水槽试验采取10中不同波高和周期的工况，对比空投波浪测量浮标与波高仪的测量结果，试验结果表明，浮标的测量误差在10%以内，达到测波标准。

Experimental study on the new wave measurement method of air-launched buoys using a MEMS accelerometer

In our study, the method of wave measurement using the frequency-domain attenuation integral algorithm is proposed to solve the problem of low accuracy of an air-launched wave measurement buoy that consists of a MEMS acceleration sensor, and the method is analyzed by conducting simulation experiments in a multifunction pond. The algorithm transforms acceleration and attitude angle measured by a MEMS accelerometer into the waveform of a buoy''s motion. First, vertical acceleration is obtained by processing accelerations and attitude angles. The complex conjugate of acceleration in a frequency domain is obtained using Discrete Fourier Transform, and then a control function is introduced for decreasing low-frequency noise. The vertical displacement of a buoy can be acquired by frequency-domain integration, Inverse Discrete Fourier Transform, and time-domain integration. Finally, wave patterns are obtained by post processing. Multifunction pond experiments were conducted or simulated using 10 different wave heights and wave periods to compare the data measured by both air-launched wave buoy and wave height gauge. It is found that all the measurement errors of the air-launched buoy are less than 10% when the results are compared with the buoy-based wave measurement system, and it confirms an improved accuracy of new proposed method.