School of Civil Engineering, Tianjin University, Yaguan Road No.135, Haihe Education Park, Jinnan District, Tianjin 300350, China.
National Ocean Technology Center, Jieyuanxidao Road No.219, Nankai District, Tianjin 300112, China.
Sensors (Basel). 2019 Jan 28;19(3):541. doi: 10.3390/s19030541.
In recent years, the GPS wave buoy has been developed for in situ wave monitoring based on satellite GPS signals. Many research works have been completed on the GPS-based wave measurement technology and great progress has been achieved. The basic principle of the GPS wave buoy is to calculate the movement velocity of the buoy using the Doppler frequency shift of satellite GPS signals, and then to calculate the wave parameters from the movement velocity according to ocean wave theory. The shortage of the GPS wave buoy is the occasional occurrence of some unusual values in the movement velocity. This is mainly due to the fact that the GPS antenna is occasionally covered by sea water and cannot normally receive high-quality satellite GPS signals. The traditional solution is to remove these unusual movement velocity values from the records, which requires furthering extend the acquisition time of satellite GPS signals to ensure there is a large enough quantity of effective movement velocity values. Based on the traditional GPS wave measurement technology, this paper presents the algorithmic flow and proposes two improvement measures. On the one hand, the neural network algorithm is used to correct the unusual movement velocity data so that extending the acquisition time of satellite GPS signals is not necessary and battery power is saved. On the other hand, the Gaussian low-pass filter is used to correct the raw directional wave spectrum, which can further eliminate the influence of noise spectrum energy and improve the measurement accuracy. The on-site sea test of the SBF7-1A GPS wave buoy, developed by the National Ocean Technology Center in China, and the gravity-acceleration-type DWR-MKIII Waverider buoy are highlighted in this article. The wave data acquired by the two buoys are analyzed and processed. It can be seen from the processed results that the ocean wave parameters from the two kinds of wave buoys, such as wave height, wave period, wave direction, wave frequency spectrum, and directional wave spectrum, are in good consistency, indicating that the SBF7-1A GPS wave buoy is comparable to the traditional gravity-acceleration-type wave buoy in terms of its accuracy. Therefore, the feasibility and validity of the two improvement measures proposed in this paper are confirmed.
近年来，基于卫星 GPS 信号的 GPS 波浪浮标已被开发用于现场波浪监测。基于 GPS 的波浪测量技术已经完成了许多研究工作，并取得了很大的进展。GPS 波浪浮标基本原理是利用卫星 GPS 信号的多普勒频移计算浮标运动速度，然后根据海浪理论从运动速度计算波浪参数。GPS 波浪浮标的缺点是运动速度偶尔会出现一些异常值。这主要是因为 GPS 天线偶尔会被海水覆盖，无法正常接收高质量的卫星 GPS 信号。传统的解决方案是从记录中删除这些异常的运动速度值，这需要进一步延长卫星 GPS 信号的采集时间，以确保有足够数量的有效运动速度值。本文基于传统的 GPS 波浪测量技术，提出了算法流程，并提出了两项改进措施。一方面，利用神经网络算法对异常运动速度数据进行修正，从而无需延长卫星 GPS 信号的采集时间，节省电池电量。另一方面，利用高斯低通滤波器对原始的方向波谱进行修正，从而进一步消除噪声谱能量的影响，提高测量精度。本文重点介绍了由中国国家海洋技术中心开发的 SBF7-1A GPS 波浪浮标和重力加速度式 DWR-MKIII Waverider 浮标在现场的海试情况。对两个浮标采集的波浪数据进行了分析和处理。从处理结果可以看出，两种浮标获取的海洋波浪参数，如波高、波周期、波向、波谱和方向波谱，具有较好的一致性，表明 SBF7-1A GPS 波浪浮标在精度上可与传统的重力加速度式波浪浮标相媲美。因此，本文提出的两项改进措施的可行性和有效性得到了验证。
