星载高层大气风场原位探测技术与测试分析

Satellite-borne In-situ Measurement Technologies and Testing Analysis of Thermospheric Neutral Wind

采用平板型碳纳米管冷阴极作为电子发射体,基于电子发射材料的性能与几何特征,设计了以直流电子枪为结构基础的均匀场离子源,在栅极和阳极间设计聚焦极,阳极与电离区之间增加双层屏蔽栅网形成电场,对离子和电子产生区进行有效分离,确保出射电子束的能量单一且方向一致,并结合具有较高速度分辨率的阻滞势速度分析器,研制了可获取高精度中性风速的星载高层大气风场原位探测仪(SSTNWI)。仿真计算和对实物的测试分析表明,风速测量误差在平均风速100 m/s时仅为10%左右,高于“通信/导航中断预报系统”卫星(C/NOFS)的轨道风传感器,中性风速测不准引起的轨道预报误差可下降到优于1.0%,未来有望应用于火星等行星和地球卫星的大气探测任务。

According to the requirement of obtain the high accuracy orbital neutral wind speed,satellite-borne in-situ thermospheric neutral wind instrument(SSTNWI)with uniform field ion source and velocity analyzer has been developed.The uniform field ion source using flat plate cold cathode electron emitter is based on the structure of a DC electron gun.According to the performance and geometry of the electron emitter material,the focus electrode of the ion source is designed between the grid and anode,and a double-layer shielding grid is added to effectively separate the electric field from the ion production area and electron production area.This design ensures the impact of electron ionization to the velocity distribution of neutral gas can be minimized and the consistency of the energy and direction of the emitted electron beam.Combined with the velocity analyzer with the retarding potential analysis method,the speed resolution is improved.The simulation and the test verification results show that the measurement accuracy of neutral wind speed is better than the Ram Wind Sensor onboard the Air Force’s Communications/Navigation Outage Forecast System(C/NOFS)satellite.The neutral wind velocity measurement accuracy of the detector is better than 10 m/s,and the error of orbital prediction from the neutral wind speed measurement is decreased to less than 1.0%.This instrument is expected to be applied to atmospheric exploration missions of Mars,other planets or Earth satellites in the future.