| Shortwave radar is different from microwave radar, it transmits and receives electromagnetic wave from refraction of Flayer, it can detect object out of stadia under tangent that moves over radar ,because it isn't restricted within curvature of earth. The detecting space of the radar is three-dimensional space and the number of square kilometer is over millions, the number of three-dimensional is over multimillion.This paper expounds that errors of the array effect on the performance of the antennas by analyzed the performance of the phased array antennas and how to correct the errors. The transmitting channel and the receive channel of radar is maken up of lager antenna and lager radio-frequency cable. calibration for phased array antennas in near field is mature technology, but it isn' t fit to apply in this case, no other than to apply technique of internal monitor and external monitor.The paper describes design method for internal monitor or external monitor to improve the precision. The inconsistent phase owning to long cable must be resolved. The effect of multipath that electromagnetic wave spreads in the space and how to resolve it. the interference of entironment mustbe taken out when dectecting singal. |
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