非相干散射雷达的高信噪比空间物体距离测量方法

The range measurement of space object with high signal to noise ratio based on the incoherent scatter radar

非相干散射雷达是目前地基电离层探测的强大手段,同时在空间物体探测方面也具有重要应用前景.当空间物体回波信噪比很高时,可以利用单个脉冲进行目标检测,而无需相干积累.非相干散射雷达常采用相位编码脉冲,在单个相位编码脉冲内存在多次相位翻转,此相位翻转在接收机滤波后显示一定坡度,通过搜索此坡度曲线上具有最大斜率的坡度点可高精度确定发射-接收回波脉冲内各对应相位翻转的时间差以及对应的距离,对这些距离值进行加权最小二乘拟合,即可给出该回波脉冲对应的空间物体距离及误差估计值.利用欧洲非相干散射科学联合会(European Incoherent Scatter Scientific Association,EISCAT)实测数据分析发现,距离误差可达数十米量级,远优于以往的基于发射-接收回波脉冲前沿时间差方法.

The incoherent scatter radar（ISR）is a main tool for monitoring the ionosphere on the ground,and can also be used to detect the space objects.When the signal to noise ratio is a bit high,only one pulse is needed to detect the space object and the coherent integration is unnecessary.There usually exist many phase flips in the radar phase-modulated pulses.When the echo pulse with phase flips is filtered by the receiver,the resulting phase flips are not sharp but consist of many slopes.By investigating the echo amplitude variation within this slope,the time difference between the transmission and reception subpulse and then the range measurements are known.Then all these range measurements during one pulse are applied to a weighted least-square fitting,which gives the range and its error estimation.By analyzing the EISCAT raw data,it is found that the range error is about several tens of meters,which is far better than that from the frequently-used method based on time difference between the transmission and reception pulse.