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首页> 外文学位 >Development of internally-calibrated, direct detection millimeter-wave radiometers to improve remote sensing of wet-tropospheric path delay.
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Development of internally-calibrated, direct detection millimeter-wave radiometers to improve remote sensing of wet-tropospheric path delay.

机译：开发内部校准的直接检测毫米波辐射计，以改善对湿对流层路径延迟的遥感。

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摘要

Satellite ocean altimeters measure the sea surface height by emitting a radar pulse and measuring the time for it to propagate to the surface, bounce off and return to the satellite. Assuming speed-of-light propagation, the sea surface height can be determined. However, water vapor in the atmosphere, which is highly variable both temporally and spatially, reduces the propagation speed of these radar signals, in turn increasing the round-trip radar propagation time, leading to substantial errors in the sea surface height estimation. This delay in the arrival time of radar pulse returns is referred to as wet-tropospheric path delay.;Past and current satellite ocean altimeters include nadir-viewing, co-located 18-34 GHz microwave radiometers to measure wet-tropospheric path delay with a precision of 1 cm. However, due to the large antenna footprint sizes at these frequencies, the accuracy of wet path retrievals is substantially degraded within 40 km of coastlines, and retrievals are not provided over land. Because footprint diameter is directly proportional to wavelength for the same antenna aperture size, a viable approach to improve their capability is to add wide-band millimeter-wave window channels in the 90-175 GHz band, thereby achieving finer spatial resolution for a fixed antenna size.;To address this need, an internally-calibrated, wide-band, cross-track scanning airborne microwave and millimeter-wave radiometer has been collaboratively developed between Colorado State University (CSU) and Caltech/NASA's Jet Propulsion Laboratory (JPL). This airborne radiometer, referred to as the High Frequency Airborne Microwave and Millimeter Wave Radiometer (HAMMR) includes microwave channels at 18.7, 23.8, and 34.0 GHz at both Quasi-H and Quasi-V polarizations, millimeter-wave window channels at 90, 130, and 168 GHz, as well as temperature and water vapor sounding channels near the 118 and 183 GHz absorption lines, respectively. Since this instrument also serves as a prototype for potential future Earth science missions, substantial effort has been devoted to minimizing the mass, size and power consumption of the radiometer. Preliminary airborne measurements of the HAMMR demonstrate the reliable and robust operation of the millimeter-wave window and sounding channels on an airborne platform, as well as the improvement in spatial resolution that they provide, over that of the traditional microwave channels.
机译：卫星海洋高度计通过发射雷达脉冲并测量其传播到地面，弹起并返回卫星的时间来测量海面高度。假设光传播的速度，可以确定海面高度。但是，大气中的水蒸气在时间和空间上都高度可变，从而降低了这些雷达信号的传播速度，进而增加了往返雷达的传播时间，从而导致海平面高度估计中的重大误差。雷达脉冲返回的到达时间的这种延迟称为“湿对流层路径延迟”。过去和当前的卫星海洋高度计都包括天底观测仪，位于同一地点的18-34 GHz微波辐射计可以测量湿对流层路径延迟，而精度为1厘米。但是，由于在这些频率下天线覆盖区尺寸较大，因此在海岸线的40 km范围内，湿路径取回的准确性会大大降低，并且无法在陆地上进行取回。因为对于相同的天线孔径，足迹直径与波长成正比，所以一种提高其能力的可行方法是在90-175 GHz频带中添加宽带毫米波窗口信道，从而为固定天线实现更好的空间分辨率为了满足这一需求，科罗拉多州立大学（CSU）和加州理工学院/ NASA的喷气推进实验室（JPL）合作开发了一种内部校准的宽带，跨轨扫描机载微波和毫米波辐射计。这种机载辐射计，称为高频机载微波和毫米波辐射计（HAMMR），包括在准H和准V极化下分别为18.7、23.8和34.0 GHz的微波信道，以及在90、130处的毫米波窗口信道，168 GHz和168 GHz，以及分别位于118和183 GHz吸收线附近的温度和水蒸气探测通道。由于该仪器还可以作为未来潜在地球科学任务的原型，因此已竭尽全力使辐射计的质量，尺寸和功耗降至最低。 HAMMR的初步机载测量表明，机载平台上毫米波窗口和测深通道的可靠，可靠运行以及与传统微波通道相比提供的空间分辨率有所提高。

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  • 作者

    Hadel, Victoria D.;

  • 作者单位

    Colorado State University.;

  • 授予单位 Colorado State University.;
  • 学科 Electrical engineering.;Atmospheric sciences.;Electromagnetics.
  • 学位 M.S.
  • 年度 2015
  • 页码 224 p.
  • 总页数 224
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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