The medium frequency radar uses the circular polarization echoes to retrieve the wind fields and the electron density in the middle and upper atmosphere. To transmit and receive circular polarization echoes, a spaced antenna system, composed of a series of cross-dipoles, is used. Different demands are imposed for the circular characteristics in the echoes to retrieving the wind fields and the electron density, consequently, the receiver should be able to keep and remove the circular characteristics in the echoes. In most medium frequency radars, a hardware solution is adopted to remove the circular characteristics by making a phase adjustment to one of the two sets of signals associated with a cross dipole unit and then overlapping it with the other. Adjusting the phase at a medium frequency requires extra devices and a complicated system, what is more, the reliability of the device might be influenced by the environment. In this paper, the 4 I/Q components of a cross dipole unit are employed to compose the I/Q components of the signals associated with the circular polarization echoes. This method is very simple, and it only involves some basic calculations and judgments at each point. Theoretical analyses and numeral simulations show that this method is effective in removing the polarization characteristics.
AO Jun
,
WANG Liming
,
CHEN Jinsong
,
LI Na
. A new approach to receive circular polarization echoes on medium frequency radar[J]. Science & Technology Review, 2015
, 33(5)
: 104
-108
.
DOI: 10.3981/j.issn.1000-7857.2015.05.017
[1] Briggs B H. The analysis of spaced sensor records by correlation techniques[C]//Handbook for Middle Atmosphere Program. Illinois. University of Illinois, 1984: 166-186.
[2] Gardner F F, Pawsey J L. Study of the ionospheric D-region using partial reflections[J]. Journal of Atmospheric and Terrestrial Physics, 1953, 7(3): 321-344.
[3] 桂质廷. 地磁及电离层电波传播[M]. 武汉: 武汉大学出版社, 1986: 117-121. Gui Zhiting. Geomagnetism and wave propagation in ionosphere[M]. Wuhan: Wuhan University Press, 1986: 117-121.
[4] Hunsucker R D, Hargreaves J K. The high-latitude ionosphere and its effects on radio propagation[M]. Cambridge: Cambridge University Press, 2003: 527-532.
[5] 李娜, 陈金松, 赵蕾, 等. 基于MF雷达观测的D区日食效应的研究[J]. 地球物理学报, 2011, 54(4): 942-949. Li Na, Chen Jinsong, Zhao Lei, et al. The study of ellipse effects in D region based on MF radar measurement[J]. Chinese Journal of Geophysics, 2011, 54(4): 942-949.
[6] 李娜, 陈金松, 赵振维, 等. 利用昆明MF雷达对C级耀斑的初步研究[C]. 第十届电波年会, 武汉, 2009-11-09. Li Na, Chen Jinsong, Zhao Zhenwei, et al. Preliminary study of C level solar flare using MF radar in Kunming[C]. The 10th Chinese National Symposium on Radio Propagation, Wuhan, China, November 9, 2009.
[7] 杨涛, 周莹莉, 曾繁清, 等. 利用全相关分析方法确定大气风场[J]. 电 波科学学报, 2003, 18(3): 324-336. Yang Tao, Zhou Yingli, Zeng Fanqing, et al. Wind field measurement by the full correlation analysis method[J]. Chinese Journal of Radio Science, 2003, 18(3): 324-336.
[8] 孔金瓯. 电磁波理论[M]. 北京: 电子工业出版社, 2003: 15-21. Kong Jin'ao. Electromagnetic waves theory[M]. Beijing: Publishing House of Electronics Industry, 2003: 15-21.
[9] 赵蕾, 陈金松, 李娜, 等. 昆明MF雷达及初步探测结果[J]. 空间科学 学报, 2011, 31(1): 27-33. Zhao Lei, Chen Jinsong, Li Na, et al. MF Radar in Kunming and its preliminary observation results[J]. Chinese Journal of Space Science, 2011, 31(1): 27-33.
[10] Richards M A. 雷达信号处理基础[M]. 北京: 电子工业出版社, 2008: 12-15. Richards M A. Fundamental of radar signal processing[M]. Beijing: Publishing House of Electronics Industry, 2008: 12-15.
