收稿日期: 2005-11-11
修回日期: 2006-04-18
网络出版日期: 2006-07-15
基金资助
国家海洋863项目“基于卫星定位系统的海面风速和风向探测技术”（编号：2002AA639190）资助.
Measuring Soil Moisture Using Reflected GPS Signals
Received date: 2005-11-11
Revised date: 2006-04-18
Online published: 2006-07-15
在水文、气候、农业等问题的研究中，土壤湿度信息十分重要。近年来，利用GPS系统进行遥感的新方法，已经越来越多地引起研究者们的关注。特别是GPS卫星广播的L1（1.57542GHz）频率信号，是土壤湿度遥感的最佳频率。反射GPS信号功率是土壤介电常数的函数，而土壤介电常数又和土壤湿度有关。根据这一原理，美国国家航空与航天局于2002年进行了基于地表面反射GPS信号的遥感土壤湿度实验。结果证明反射GPS信号对土壤湿度特性十分敏感，由于植被的影响对反射率进行了修正，并用此方法模型与其它方法进行了比较。在利用GPS遥感土壤湿度方面，研制高增益天线，更好的修正信号波动的影响，发展更加完善的遥感土壤湿度方法等是今后在此项研究中所要解决的问题。
宋冬生 , 关止 , 赵凯 . 利用反射GPS信号遥感土壤湿度[J]. 地球科学进展, 2006 , 21(7) : 747 -750 . DOI: 10.11867/j.issn.1001-8166.2006.07.0747
]Soil moisture plays a significant role in the research of hydrology, climatology, and agriculture. As a new tool, this remote sensing method using reflected GPS signals has attracted much more attention. The GPS broadcasts a carrier signal at 1.57542GHz which is an optimal frequency for remote sensing soil moisture. The reflected GPS signal as a function of permittivity relates to the soil moisture. The experimental result proves that the reflected GPS signal is sensitive to the surface soil moisture characteristic. The reflectivity is corrected under the vegetation effects and comparison of the GPS and the other model is investigated. Developing the high gain antenna, correcting the effects of signal fluctuation and improving the method of remote sensing soil moisture are the main issues we should resolve in future work.
Key words： Soil moisture; Reflected GPS signal; GPS bistatic radar.
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