A 94 GHz dual-mode imaging radarometer for remote sensing
A 94 GHz dual-mode imaging radarometer for remote sensing
复制标题
用于遥感的 94 GHz 双模式成像雷达仪
DOI：
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
D. Macfarlane
中科院分区：
文献类型：
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作者：
D. Robertson;D. Macfarlane
我们报告我们的94 GHz双模雷达/辐射成像仪，AVTIS的持续发展。到目前为止，我们一直致力于改进雷达模式，现在可以获得最先进的远程高分辨率雷达图像。最近，我们致力于改进和集成辐射测量模式，以完成双模式功能。单基地架构的一个值得注意的问题是雷达发射机通过环行器/天线组件泄漏，即使发射机信号严重衰减。一个相关的问题是，由于所使用的崩越乘法器和功率放大器，本机振荡器信号中的AM噪声水平很高。这种远离载波的噪声与泄漏相结合，降低了接收机的灵敏度，并提高了本底噪声，使接收机的噪声温度约为6000 K。这产生了在4 ms内2K的热分辨率，被认为足以用于预期的火山学应用。相比之下，测试与高功率肖特基二极管乘法器链作为LO源产生了750 K的噪声温度在一个单独的辐射计。热校准也是一个值得关注的问题，我们已经实现了一个中频噪声添加电路，其中辐射计在场景和冷热中频噪声参考之间交替。这解释了IF放大器中的主要接收机波动，但天空倾斜曲线用于校准整体响应。虽然雷达已经能够制作表面反射率重叠的高分辨率地形图，但希望共同校准的辐射亮度温度数据将导致更好地了解被测量地形的发射率和表面粗糙度。
We report on the continued development of our 94GHz dual-mode radar/radiometric imager, AVTIS. To date we have concentrated on refining the radar mode and can now acquire state-of-the-art long range, high resolution radar images. More recently we have worked to improve and integrate the radiometric mode, to complete the dual-mode functionality. One notable problem of the monostatic architecture is that of radar transmitter leakage via the circulator/antenna assembly, even with the transmitter signal heavily attenuated. A related issue is the high level of AM noise in the local oscillator signal due to the IMPATT multipliers and power amplifiers used. This far-off-the-carrier noise, in combination with the leakage, desensitises the receiver and raises the noise floor to give a receiver noise temperature of approximately 6000K. This yields a thermal resolution of 2K in 4ms that is considered adequate for the intended volcanological application. In comparison, tests with a high power Schottky diode multiplier chain as the LO source has yielded a noise temperature of 750K in a separate radiometer. Thermal calibration is also of concern and we have implemented an IF noise adding circuit in which the radiometer alternates between the scene and hot and cold IF noise references. This accounts for dominant receiver fluctuations in the IF amplifiers but sky tipping curves are used to calibrate the overall response. Whilst the radar is already capable of producing high resolution topographic maps with surface reflectivity overlaid, it is hoped that co-aligned radiometric brightness temperature data will lead to a better understanding of the emissivity and surface roughness of the terrain being surveyed.
使用便携式雷达对不断增长的熔岩穹丘进行成像
DOI：
10.1029/2006eo230003
发表时间：
2011
期刊：
Eos, Transactions American Geophysical Union
影响因子：
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作者：
Wadge G
通讯作者：
Wadge G