电离层对月基对地观测平台辐射成像的影响
Influence of ionosphere on radiation imaging for Moon-based Earth observation platform
袁立男 1廖静娟 2董书莉 1武文波 1贺强民1
作者信息
- 1. 北京空间机电研究所,北京 100094
- 2. 中国科学院空天信息创新研究院,北京 100094
- 折叠
摘要
月基对地观测是一种全新的空间观测手段,其将月球作为搭载平台对地球进行持续长期观测,具有超大可观测范围、高测绘带幅宽、多角度成像、高时间分辨率和长使用寿命等优势.地球电离层位于地表以上至1 000 km的高空区域,是影响月基对地观测成像质量的重要因素.为探索月基对地观测平台下热红外及微波辐射传输特性,研究开展了地球电离层对月基对地观测平台热红外和微波辐射成像影响分析的工作,并模拟不同纬度区域月基微波辐射亮温衰减值.首先根据Chapman分布定量化分析电离层电子浓度、折射率变化规律,再结合观测天顶角、碰撞频率等参数计算穿过电离层过程中不同高度处衰减及传输路径,最终采用积分方式获取热红外和微波在电离层中能量衰减量.结果表明,月基对地观测平台热红外和微波成像链路中电离层中造成的能量衰减与碰撞频率、热红外波长和观测天顶角有关,且地球电离层对月基对地观测平台微波成像的影响大于热红外成像的影响.此外,低纬度区域月基微波辐射受电离层衰减影响较大,月基微波亮温值降低约1.304 K;中纬度次之.
Abstract
Moon-based Earth observation is a new space observation method,which conducts continuous and long-term observations of the Earth through the Moon platform.It has unique disadvantages such as large viewing angle,high width,multi-angle imaging,high time resolution,and long design life.The ionosphere is located in the high-altitude area up to 1 000 km above the Earth's surface,and it is an important factor affecting the quality of Moon-based Earth observation imaging.To explore the thermal infrared and microwave radiation characteristic for Moon-based Earth observation,the ionosphere influence on microwave imaging for Moon-based Earth observation platform was analyzed,and the attenuation value in microwave radiation brightness temperature under different latitude areas was simulated.First,the ionospheric electron concentration and the refractive index change law were estimated based on the Chapman distribution.Then the attenuation for different heights as well as transmission paths during ionosphere passing through were calculated,which used the observed zenith angle,collision frequency,etc.Finally,the integration method was adopted to obtain the thermal infrared and microwave energy attenuation in the ionosphere.Results show that the thermal infrared and microwave energy attenuation in the ionosphere of Moon-based Earth observation platform depends on the collision frequency,band,and viewing zenith angle.The ionosphere has greater effect on thermal infrared imaging than microwave imaging for Moon-based Earth observation.In addition,the Moon-based microwave brightness temperature value in the low latitude regions is greatly affected by the ionosphere attenuation with a decrease of about 1.304 K,followed by the mid-latitude regions.
关键词
月基对地观测/热红外/微波/电离层/能量衰减/折射率Key words
Moon-based Earth observation/thermal infrared/microwave/ionosphere/energy attenuation/refractive index引用本文复制引用
基金项目
国家自然科学基金重大项目(41590855)
中国科学院前沿科学重点研究计划项目(QYZDY-SSW-DQC026)
出版年
2024
国家科技期刊平台
NSTL
万方数据