MRU位置偏差二次探测及多波束异常条纹地形消除方法研究

Secondary Detection of MRU Position Deviation and Terrain Elimination of Multi-beam Abnormal Stripe

  • 摘要: 针对多波束测深数据中常出现的沿航迹向异常条纹在浅水影响显著,传统方法机理不完善和异常消除不彻底问题,基于多波束数据处理原理分析成因,认为主要由于诱导涌浪未补偿或姿态传感器(motion reference unit,MRU)位置偏差量测不准带来的诱导涌浪补偿残余所致,为此提出基于往返测线测深点对深度不符值的MRU位置偏差二次分段探测方法和异常条纹消除方法。首先通过最近平面点搜索,发现同名点对;然后分段构建深度不符值与欲探测的MRU位置偏差关系模型,并借助支持向量机回归参数抗差估计法估计位置偏差;最后给出修正模型,消除测深数据中异常条纹影响。实验表明,所提方法从机理上较彻底地消除了异常测深条纹影响,也为MRU安装偏差探测提供了一种新方法。

     

    Abstract:
    Objectives The anomaly along-track stripes which often appear in the multi-beam sounding data have significant influence on shallow water. Aiming at the problem that the mechanism of traditional methods is not perfect and the elimination of anomalies is not complete, the causes are analyzed based on the multi-beam data processing principle. It is considered that the main reason is induced heave compensation residual caused by uncompensated induced heave or inaccurate measurement of position deviation of motion reference unit(MRU).
    Methods For this reason, a method of position deviation detection and elimination of abnormal stripes based on the sounding data of common coverage area is proposed. First, homologous point pairs are found by automatic nearest plane point searching. Second, the relationship model between the water depth difference of the homologous point and the position deviation to be detected was constructed, and the position deviation was estimated by support vector machine regression parameter robust estimation method. Finally, a modified model is given to eliminate the influence of abnormal stripes in the sounding data.
    Results Experimental results show that: (1) After the calibration of the proposed method, the standard deviation of the difference between the common coverage area of the round-trip lines decreases from 8.5 cm to 2.6 cm. (2) The mutual difference between the detection results of each section is about 1 cm. (3) The proposed method performs (significantly different) on adjacent lines with 50% and 15% overlap area, with standard deviations decreasing from 6.9 cm to 3.9 cm and from 12.9 cm to 7.6 cm, respectively. (4) Using the detected relative position deviation to correct the entire measurement area, the standard deviation of the discrepancy value in the common coverage area is reduced from 0.07 m to 0.03 m.
    Conclusions The proposed method can completely eliminate the influence of abnormal sounding stripes and provide a new method for detecting MRU installation deviation. However, the results are affected by the overlap area of the adjacent lines, so it is recommended to be performed on the round-trip lines whenever possible.

     

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