中国风云三号(FY3)卫星是国际气象组织组网卫星之一,其搭载的微波成像仪(MWRI)可为气象研究、天气预报等多个领域提供有效数据。在应用MWRI数据进行多频率探测通道的协同反演时,必须考虑通过重采样来使不同探测频点的数据具有一致的空间分辨率。Backus-Gilbert(BG)方法是一种被广泛用于星载微波辐射计亮温数据重采样的方法。传统重采样方式应用BG方法计算辐射计单次旋转扫描得到的采样点的权重系数(预计算权重系数),并将其直接应用到所有旋转扫描获取的采样点上,进而完成全部数据的重采样。然而,在卫星仪器的采样过程中,地球椭球面等因素的影响会导致观测视场之间的相对位置发生改变,将预计算权重系数直接应用到全部数据会给重采样带来误差。因此,本文提出一种结合天线方向图投影定位方法的重采样方式,详细分析了MWRI数据在不同轨道位置的重采样效果。实验结果表明,本文采用的重采样方式能够在MWRI的不同的通道组合上修正传统重采样方式造成的平均1.32 K的亮温误差。本文指出并修正了重采样亮温的一种误差来源。未来在使用多频率探测通道数据协同反演地球物理参数时,根据反演参数对亮温变化的敏感程度,应用本文方式获取的重采样数据可以获得更准确的反演结果。

As an important load of airborne/spaceborne passive microwave remote sensing, fully polarized microwave radiometer is widely used to the measurement of wind vector and salinity on sea surface. The retrieval of ocean surface parameters requires high accuracy data of radiometer. In recent years, the data correction scheme of fully polarized radiometer is common, but the attitude problem of radiometer is not paid enough attention. This paper establishes a full link transfer model for a fully polarized microwave radiometer, and focus on analysing the impact of aircraft attitude on various parameters. This paper aims to draw researchers' attention to attitude control of fully polarized microwave radiometer. Through the model established in this paper, the influence of attitude on fully polarized microwave radiometers is clarified and corrected, then rapidly correction can be achieved. Through simulation model, the impact of different attitudes on data can be calculated in advance before flight tests, and can provide guidance for attitude control. Using the corrected data for wind vector analysis, the deviation of wind direction is within 10 circle , which also verifies the accuracy of the model in this paper. The model proposed in this paper can achieve fast and accurate correction of radiometer parameters and the error prediction caused by attitude, which provides a strong guarantee for the inversion of sea surface parameters.

Spaceborne passive microwave sensor is a kind of remote sensing that uses high-sensitivity receivers to detect natural microwave radiation from scenes and targets. Passive microwave remote sensor also refers to microwave radiometer. Microwave radiometers have been used for remote sensing of the Earth from space for more than fifty years. At present, microwave radiometers have become the main payload of meteorological and oceanographic satellites, playing an important role in numerical weather prediction, marine environment monitoring and global climate change research. This article analyzes and summarizes the following points. Firstly, passive microwave remote sensing technology and its application development. Secondly, the development trend of passive microwave remote sensing technology and its key technical issues. Thirdly, for the quantitative application of passive microwave remote sensing in China, some thoughts and suggestions are put forward in terms of product and data processing procedures, as well as standardization on algorithm for deriving different level products, calibration/validation of brightness temperature and geophysical parameters. The contents of this article aim at promoting much wider application of passive microwave remote sensing data and maximizing the application efficiency of passive microwave remote sensing technology.

微波湿温探测仪（MWHTS）的通道响应函数（SRFï¼‰ä¸€èˆ¬è¢«è®¤ä¸ºè¿‘ä¼¼äºŽçŸ©å½¢å‡½æ•°ï¼Œç„¶è€Œä»Žå®žé™ SRF的测试数据来看，MWHTS各个频段不同通道的SRFå­˜åœ¨ä¸€å®šçš„å¸¦å† æ³¢åŠ¨ã€‚æœ¬æ–‡åˆ©ç”¨å¤§æ°”è¾å°„ä¼ è¾“æ¨¡æ‹Ÿå™¨ï¼ˆARTS）模拟了MWHTS中118 GHzå„é€šé“ä¸åŒåœºæ™¯çš„äº®æ¸©è°±ï¼Œå¹¶è¾“å ¥è‡³å‰æœŸå»ºç«‹çš„MWHTSç³»ç»Ÿä»¿çœŸæ¨¡åž‹ä¸­ï¼Œé€šè¿‡å®šæ ‡å¾—åˆ°äº†ä»ªå™¨çš„è¾“å‡ºäº®æ¸©ï¼Œè¿›è€Œè¯„ä¼°å®žæµ‹SRFå¯¹äº®æ¸©æµ‹é‡åŠå ¶åæ¼”çš„å¤§æ°”æ¸©åº¦å»“çº¿çš„å½±å“ï¼Œå¹¶åˆ©ç”¨å«æ˜Ÿå®žæµ‹æ•°æ®è¿›è¡Œäº†å¯¹æ¯”éªŒè¯ã€‚ç»“æžœè¡¨æ˜Žï¼Œäº®æ¸©åå·®ä¸Žå®žé™ SRFçš„å¸¦å† æ³¢åŠ¨å‘ˆçŽ°çº¿æ€§æ­£ç›¸å ³çš„å ³ç³»ï¼Œå½“å¸¦å† æ³¢åŠ¨å¤§äºŽ3 dB时，亮温偏差可以达到0.2—0.5 K。SRFçš„å¸¦å† æ³¢åŠ¨ä¼šé€ æˆå¤§æ°”æ¸©åº¦å»“çº¿åæ¼”è¯¯å·®ï¼Œç‰¹åˆ«æ˜¯åœ¨é«˜åº¦ä¸º1.8 km时，误差最大可以达到0.8—0.9 Kï¼Œè¯¥ä»¿çœŸç»“æžœä¸Žå«æ˜Ÿå®žæµ‹æ•°æ®ç»“æžœä¸€è‡´ã€‚å› æ­¤åœ¨ä½¿ç”¨æ•°æ®åŒåŒ–æ–¹æ³•å¯¹æ•°å€¼å¤©æ°”é¢„æŠ¥ï¼ˆNWPï¼‰è¿›è¡Œæ¨¡æ‹Ÿæ—¶ï¼Œéœ€è¦ç‰¹åˆ«æ³¨æ„å ·æœ‰è¾ƒå¤§SRFå¸¦å† æ³¢åŠ¨çš„é€šé“æ‰€å¼•èµ·çš„äº®æ¸©åå·®ï¼Œè¿™å¯¹äºŽæœªæ¥å«æ˜Ÿæ•°æ®çš„åº”ç”¨å ·æœ‰é‡è¦çš„ç ”ç©¶ä»·å€¼ã€‚

APMR（Airborne full Polarization Microwave Radiometer） is one of the main loads of the national major scientific and technological infrastructure aviation remote sensing system, which is used to obtain the polarization microwave radiation electric field information from the earth’s surface and atmosphere, so as to retrieve the physical parameters of the earth’s surface and atmosphere. APMR is a passive microwave remote sensor with 5 frequency points, and the central frequency points are 10.7 GHz, 18.7 GHz, 23.8 GHz, 37.0 GHz and 90 GHz respectively. Among them, horizontal and vertical polarization reception is adopted at 23.8 GHz and 90 GHz; and full polarization reception is adopted at 10.7 GHz,18.7 GHz and 37.0 GHz, and four Stokes parameter brightness temperatures of observed scene radiation are received at the same time. Based on the introduction of the main technical characteristics and basic performance indexes of the APMR system of China’s first airborne full polarization microwave radiometer, this paper puts forward a two-step data processing method which consists of full polarization calibrationand sea surface brightness temperature extraction, so as to obtain the four Stokes parameter information of sea surface brightness temperature, which can be used for the inversion of sea surface wind direction, wind speed and other parameters. Sea surface test of APMR have been carried out in Dongying in June 2020. The sea surface brightness temperature extracted from the experimental results is consistent with the expected situation, which verifies the working performance of the instrument and the extraction method of sea surface brightness temperature, and provides a new technical means for the future airborne platform to obtain ocean surface parameters.

A digital-correlation full-polarized microwave radiometer is an important passive remote sensor, as it can obtain the amplitude and phase information of an electromagnetic wave at the same time. It is widely used in the measurement of sea surface wind speed and direction. Its configuration is complicated, so the error analysis of the instrument is often difficult. This paper presents a full-polarized radiometer system model that can be used to analyze various errors, which include input signal models and a full-polarized radiometer (receiver) model. The input signal models are generated by WGN (white Gaussian noise), and the full-polarized radiometer model consists of an RF front-end model and digital back-end model. The calibration matrix is obtained by solving the overdetermined equations, and the output voltage is converted into Stokes brightness temperature through the calibration matrix. Then, we use the four Stokes parameters to analyze the sensitivity, linearity, and calibration residuals, from which the simulation model is validated. Finally, two examples of error analysis, including gain imbalance and quantization error, are given through a simulation model. In general, the simulation model proposed in this paper has good accuracy and can play an important role in the error analysis and pre-development of the fully polarized radiometer.

An electron cyclotron resonance ion source has been developed in RIAMB for 100 keV ion implantation. Its magnetic field was produced by NdFeB permanent magnet and its outline dimension is about 160 mm in diameter and 150 mm in height. It operates in pulse mode, at nitrogen discharge, 100 kV extraction voltages, and 60 kV acceleration voltages; more than 40 mA ion pulse current was extracted from seven emission apertures of 3.5 mm in diameter. Even ion beam over an area of about 250 mm in diameter has been obtained on the sample stage at a distance about 1000 mm from the emission aperture.