Design and Development of Microwave Humidity Sounder for FY-3 Meteorological Satellite
Design and Development of Microwave Humidity Sounder for FY-3 Meteorological Satellite
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DOI：
10.11834/jrs.20080226
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Wang Zhenzhan
中科院分区：
文献类型：
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作者：
Wang Zhenzhan
风云三号气象卫星是中国的第二代极轨气象卫星，微波湿度探测仪是其主要载荷之一。本文简要介绍了微波辐射计探测大气湿度的基本原理和风云三号卫星上微波湿度探测仪的技术指标。给出了微波辐射计的框图和工作方式。微波辐射计是一种双频五通道毫米波辐射计，是一种基于外差接收机的全功率微波辐射计。150 GHz辐射计有V和H两个极化，183.31 GHz辐射计有三个通道，分别为183.31±1 GHz、183.31±3 GHz和183.31±7 GHz。通过对天线波束的跨航迹扫描，实现了约2700公里的条带宽度。最终测试证明，MWHs的性能满足技术要求。MWHS由天线和接收单元、电子单元和电源单元三个单元组成。天线和接收单元收集大气辐射。接收信号被聚焦到喇叭馈电和高频前端的第一单元，然后由双边带混频器下变频到中频；电子单元对低频信号进行数字化处理，控制扫描机构和测量星载热目标的物理温度进行校准，并通过1553B数据总线与卫星通信。电源单元进行DC/DC转换，将直流线分配到各个子组件并在标称单元和冗余单元之间切换。一个电机驱动150 GHz和183.31 GHz通道的两个独立的反射器，扫描周期为2.667。天线主波束以1.71的恒定周期在观测条带(距最低点±53.35°)的横向扫描，在每个周期内进行两点定标以校准接收机增益和噪声。定标是通过观测星载热目标和冷天的背景辐射来实现的。
FY-3 meteorological satellite is the 2nd generation of China's polar-orbit meteorological satellite,and the Microwave Humidity Sounder(MWHS) is one of its main payloads.The basic principle of atmospheric humidity sounding by microwave radiometer and the technical specifications of MWHS onboard FY-3 satellite are briefly introduced in this paper.The block diagram and operating modes of MWHS are presented.MWHS is a dual-frequency,five-channel millimeter wave radiometer which is a total power type microwave radiometer based on a heterodyne receiver,and performs cross-track scanning.The frequencies of MWHS include both the atmospheric transparent windows of 150GHz and water vapour absorption lines around 183.31GHz.The 150GHz radiometer has two polarizations of V and H,and the 183.31GHz radiometer has three channels of 183.31±1GHz,183.31±3GHz and 183.31±7GHz,respectively.The swath width of about 2700km is implemented by cross-track scanning of the antenna beams.Final testing verifies that the performance of MWHS satisfies technical requirements of specifications.MWHS consists of three units: antenna and receiver unit,electronic unit and power supply unit.Antenna and receiver unit collcets emission from the atmosphere. The received signal is focused to the horn-feed and the first element of the high frequency front end,and then down-converted by a double side band mixer to Intermediate Frequency;IF signal is been down-converted to Low Frequency(LF) by a detector,and then integrated.The electronic unit digitizes the LF signal, controls the scanning mechanism and measures physical temperature of the on-board hot target for calibration,and communicates with satellite through a 1553B data bus.The power supply unit performs DC/DC conversion,distributies the DC lines to the various sub assemblies and switches between the nominal and the redundant unit.One motor drives two separated reflectors for the 150GHz and the 183.31GHz channels,the scanning period is 2.667s.Main beams of the antenna scan over the observing swath(±53.35° from nadir) in the cross-track direction at a constant periodicity of 1.71s.During each period,two-point calibration are performed to calibrate the receiver gain and noise.The calibration is implemented by observing an onboard hot target and the background emission of the cold sky.