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装有短脉冲雷达高度表的Geos-3卫星于1975年4月发射到地球轨道。高度表用来精确地测量卫星到地球的距离,同时也通过记录雷达回波脉冲的波形来测量地球表面的平均粗糙度。该卫星工作在海洋上空,海面高度的变化表示地球引力场的改变,粗糙度的变化是由波浪引起的。 本文阐述了根据雷达回波脉冲波形来确定波高的方法和必须考虑的修正量。详细地讨论了定时变化对平均回波脉冲波形的影响,并指出测量这种波形的采样波门的精确校准要求是特别高的。 推导出的波高与海面实测数据进行了比较,实测数据是根据测量船关于太平洋东北部波高的报告以及海洋气象站PAPA所做的日常测量得到的。发现,通过适当的校准和调整,卫星的测量与地面的观测是一致的。在H_(1/3)的波高处的精度约为0.5米。
Geos-3 satellites equipped with short-pulse radar altimeters were launched into Earth orbit in April 1975. Altimeter is used to accurately measure the distance of the satellite from the earth, meanwhile, the average roughness of the Earth’s surface is measured by recording the waveform of the radar echo pulse. The satellite is operating above the ocean. Changes in sea level indicate changes in the Earth’s gravitational field, and changes in roughness are caused by waves. This article describes the method of determining the wave height based on the radar echo pulse waveform and the amount of correction that must be considered. The effects of timing variation on the average echo pulse waveform are discussed in detail, and the precise calibration requirements of the sample wave gate to measure this waveform are particularly high. The derived wave heights are compared with the sea surface measured data obtained from the reports of the survey vessel on the wave height in the northeastern Pacific Ocean and daily measurements by the marine weather station PAPA. It has been found that satellite measurements are consistent with ground observations through proper calibration and adjustment. The accuracy at the H_ (1/3) wave height is about 0.5 m.