共查询到19条相似文献,搜索用时 250 毫秒
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本文对一种以全功率微波辐射计为基础的新型微波辐射计———数字增益自动补偿微波辐射计进行了仿真研究。建立了微波辐射计系统各环节的数学模型并以此进行了仿真试验。仿真结果不仅证明了所建立的数学模型准确有效,而且为优化系统设计提供了重要参考,同时也为进一步实现星载环境仿真调试奠定了基础。 相似文献
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以风云三号气象卫星微波湿度计为例,通过手机信号对183.31GHz接收机的干扰实验,找到了干扰途径,进行了机理分析,并定量分析了移动通讯基站对在轨运行的星载微波辐射计的影响,给出在星载微波辐射计中预防和解决干扰的措施,并进行了实验验证。
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冰云对全球气候的显著影响,使得利用毫米波/亚毫米波辐射计探测冰云分布持续受到关注。为从辐射计亮温测量值中反演出冰云粒子参数,完善的辐射传输正演模型起到非常关键的作用。针对即将发射的冰云成像仪毫米波/亚毫米波星载辐射计,建立起了包含粒子散射在内的完整的辐射传输模型。传输模型读取大气廓线及云层粒子微观参数,仿真计算得到辐射计各通道的辐射亮温。给出了辐射传输模型的详细配置,并分析了不同通道对云层粒子的敏感性。结果表明:冰云成像仪各通道对冰云粒子、雪粒子均有很强的敏感性,但只有低频率通道能探测到水云粒子、雨粒子的变化。辐射计通道中,不同的中心频率对冰晶粒子敏感度不同,从而可使辐射计探测不同高度、不同特性的粒子。对于同一中心频率,不同频偏对应不同的大气透明度,使得辐射计可进一步探测到不同高度的云层信息。仿真工作将会为后续的毫米波/亚毫米波辐射计设计、反演算法研究等打下良好的基础。 相似文献
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从测量误差的理论角度,分析了影响微波辐射计系统测量精度的各种因素,提出了研制和应用微波辐射计系统所要依据的4个温度概念,并从应用条件角度讨论了提高陆基、机载、星载微波辐射计系统测量精度的一些具体技术方案。 相似文献
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Zhenzhan Wang Dehai Zhang Yun Li Jin Zhao 《International journal of remote sensing》2014,35(11-12):4496-4514
The atmospheric correction microwave radiometer (ACMR) is one of the main payloads for correcting atmospheric path delay in the radar altimeter on the Haiyang-2A (HY-2A) satellite. The ACMR is a three-band microwave radiometer operating at 18.7, 23.8, and 37.0 GHz. Calibration of the ACMR is important for applying its measurements to correct for atmospheric effects on the HY-2A altimeter signal transmission in the air. Therefore, a detailed introduction to the principles and specifications of the ACMR system is given first. The thermal vacuum calibration method of the ACMR is discussed and analysed, and the microwave transfer functions and related coefficients are given, especially the nonlinear coefficients derived from a test for correcting nonlinear responses between the input of antenna temperature and the output of voltage at each channel of the ACMR. Furthermore, antenna pattern correction algorithms for removing the effects of side lobe and cross-polarization are derived and their coefficients are used for in-orbit data processing. Primary calibration results are given by comparing with the similar spaceborne Jason microwave radiometer (JMR) on the Jason-1 satellite and with the advanced microwave radiometer (AMR) on Jason-2. The results of this comparison show that the data from the ACMR match well to those from the JMR and AMR. 相似文献
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Xianxun Yao Cheng Zheng Jin Zhang Jungang Miao 《International journal of remote sensing》2013,34(22):7795-7814
Synthetic aperture interferometric radiometry (SAIR) has provided an effective approach for achieving high spatial resolution in remote sensing at microwave frequencies. The radiometric sensitivity of a synthetic aperture interferometric radiometer is determined by the uncertainty in visibility samples. Generally, visibility samples can be calculated by utilizing either nominal or redundant correlation methods, such as in microwave imaging radiometry with aperture synthesis. In this paper, we use the average of results from both methods, which results in a 1.5 dB improvement in the signal-to-noise ratio (SNR) of visibility samples by assuming double side band (DSB) inphase/quadrature (I/Q) demodulation. Moreover, the requirement for the baseband signals to have a high sampling rate for optimum visibility sample uncertainty can be greatly relaxed, regardless of the type of demodulation. The receiver complexity, volume, and power consumption will be also much lower, which is critical for airborne and space-borne SAIR applications. The mathematical derivation is presented in detail followed by verifications with several experiment results based on the SAIR prototype instrument. 相似文献
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各种离散分数阶傅立叶变换DFRFT(Discrete Fractional Fourier Transform)算法的发展促进了分数阶傅立叶变换FRFT(Fractional Fourier Transform)在数字信号处理领域的应用。本文首先介绍了FRFT的定义和特性,并给出了几种DFRFT计算方法的比较。在对Ozaktas提出的DFRFT快速算法理论分析基础上,本文给出了基于TMS320C6201定点数字信号处理器DSP(Digital Signal Processor)的快速算法详细实现。该详细充分利用FFT计算和数学处理来有效降低算法的运算量。 相似文献
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机载前视风切变雷达信号处理方法分析 总被引:2,自引:1,他引:1
遭遇低空风切变是飞机失事的主要原因之一,利用机载气象雷达探测危险低空风切变的最大难题在于寻求一种好的信号处理算法,在气象信号回波功率远低于地杂波回波功率时仍有好的性能表现.介绍了机载前视风切变雷达的几种数字信号处理算法,重点讨论了脉冲对处理(PPP)法和傅立叶变换(FFT)法,分析了两种算法的原理特点,采用风切变回波模拟数据对两种算法进行了计算机仿真和性能对比分析,仿真结果表明,在一般情况下采用FFT和PPP方法估计风速的性能差异不大,在微下击暴流核心区域,都能获得对风速的良好估计. 相似文献
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综合孔径微波辐射计是被动微波遥感发展的新方向。综合孔径技术利用了以小口径天线阵列合成大的观测口径的技术,解决了在较低频率时天线物理口径要足够大才能得到期望的空间分辨率的严重缺陷。土壤湿度和海水盐度是影响全球气候和水气循环的重要因素。这些参数一般是在L波段范围观测得到,综合孔径辐射计就是减少天线孔径和重量,并最终可以观测反演出这两个参数的一项新兴技术。综合孔径辐射计不同于全功率辐射计,它测量的是视场亮温分布对于天线阵中不同基线长度的可视度函数分量。它的系统主体是稀疏天线阵和多通道相关接收机。在实际应用中,要得到土壤湿度等参数的反演,较高的系统亮温分辨率以及亮温与测量量之间的准确对应是至关重要的,这即是定标工作要完成的任务。定标直接影响微波辐射图解译和判读的准确度,是实现定量化微波遥感的前提。针对一雏综合孔径辐射计系统,给出了一种定标方案。其中分析了天线阵以及多通道相关接收机部分的定标,由得到的矩阵形式的空间频率响应信息推出了亮温图像的反演公式。 相似文献
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《中国科学:信息科学(英文版)》2012,(10):2301-2317
Sparse microwave imaging radar is a newly developed concept of microwave imaging system,which tries to combine the traditional radar imaging system with sparse signal processing theories,achieving the aim of reducing the complexity of microwave imaging systems and enhancing the system performance.In this paper,we introduce some basic concepts of sparse signal processing theory,and then apply it to the traditional radar imaging system to get the mathematical model of sparse microwave imaging system.We analyze the factors that determine the performance of sparse microwave imaging radar,including scene,waveform and platform.According to the radar model,we analyze how these factors influence the radar system and how to optimize them.Simulation results of the sparse microwave imaging radar system are also provided. 相似文献