GNSS浮标高程测量精度的影响因素研究

Research on the Influence Factors in the Precision of Height Measured by GNSS Buoy

针对高度计定标检验的需求，研制了GNSS浮标，并在天津市于桥水库和威海市石岛镇分别进行了浮标性能测试。通过对影响浮标数据处理精度的因素进行研究，为GNSS浮标数据处理方法建立了完整的技术流程，使其满足高度计定标检验的需求。结果表明：GNSS浮标可以满足高度计定标检验的需求；但需特定的数据处理方法。（1）在基准站数据处理中，卫星截止高度角选择为5°~15°，数据采集时间不少于24 h；（2）浮标数据处理模式选择为自动模式，并对其进行移动平均滤波或中值滤波处理后，流动站解算结果最优；（3） GNSS浮标的水面高程测量精度优于1 cm；（4）受到GNSS本身的限制，当浮标距离GNSS基准站越远，浮标数据的解算精度越低。

Aiming at the requirements of altimeter calibration and inspection, a GNSS buoy was developed and its performance was tested in the Yuqiao reservoir in Tianjin and Shidao town in Weihai, Shandong Province. The GNSS buoy data process was established through the research on the factors influencing buoy data processing precision. The complete technical process was built to process the GNSS buoy data, satisfying the requirements of calibration and validation of satellite altimeter. Results show that the GNSS buoy can meet the inspection requirements of altimeter calibration, but needs special data processing method： （1） In data processing in the reference station, the cut off angle of satellite should be set to 5-15°, and the data acquisition time should be no less than 24 h;（2） in order to achieve the optimal results of GNSS buoy data, the mode of data processing should be set automatic, and the moving average filter or the median filter should be used to process the raw data; （3） the precision of water surface elevation measured by GNSS buoy should be better than 1 cm; （4） confined by its own limits, the precision of GNSS buoy data solution is lower when the distance from the buoy to the GNSS reference station is farther.