评述了GPS技术目前存在的问题，包括与SLR测量之间存在的系统偏差、GPS技术本身可能存在的周年变化和GPS卫星天线相位中心的变化。
The main problems in GPS technology including the system bias to SLR, its own annual variety and the change of GPS satellite antenna phase center are also discussed.
本文是为了解决定向天线的相位中心问题，为侦测合一系统设计提供参考而展开研究的。
This paper is worked to solve the phase center of the directional antenna, accordingly to giving some references for the interception and Direction-finding system.
菲涅尔区相位修正平面天线是一种用于高功率毫米波发射系统的新型平面天线形式。
Fresnel zone phase correcting plate antenna is a new type of planar antenna which is used in high-power millimeter-wavelength radiation system.
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