弹载天线旋转对接收信号多普勒偏差的影响

由弹体自旋产生的弹载天线的旋转是引起地面测控站多普勒测速误差的一个重要因素.根据线极化信号接收原理,对弹载天线旋转条件下接收的左旋和右旋信号多普勒偏差进行了理论推导和分析.分析结果表明：左/右旋接收信号将产生幅度相等、极性相反的多普勒偏差,多普勒偏差的均值与弹载天线旋转速率在数值上相等,多普勒偏差的方差随着目标视线与天线转轴之间夹角的增大而增大.为验证理论分析结果,开展了天线转台模拟实验,实验测量得到的多普勒偏差的均值和方差与理论分析结果基本一致.最后,根据理论分析和模拟实验结果,提出在实际任务中,可采用左旋和右旋多普勒偏差均值差的一半分别对左/右旋信号的多普勒进行补偿,以减小弹载天线旋转对测速精度的影响.

Impact of Rotation of Missile-Borne Antennas on Doppler Shift of Received Signals

The rotation of antennas due to a spinning missile is the main cause of Doppler shift measured by ground stations. According to the receiving principle of linearly polarized signals, Doppler shift is analyzed for LHCP （Left- Hand Circular Polarization） and RHCP （Right Hand Circular Polarization） signals which are received from the spin- ning missile antenna. It is shown that the Doppler shifts for I.HCP and RHCP signals are equal in magnitude but op posite in polarity. The average magnitude of the Doppler shift is equal to the velocity of the rotating antenna. The variation of the Doppler shift increases with the angle between the rotation axis and signal transmit axis. The conclu sion is primarily demonstrated by a simulated experiment using a transmit antenna stabilized during the spinning stage. According to the conclusion, half of the difference of the Doppler means for LHCP and RHCP could be calcu- lated to eliminate the Doppler shift caused by the rotation of missile antennas.