公开(公告)号：US4888593A

公开(公告)日：1989-12-19

申请号：US147255

申请日：1987-12-15

申请人： Joseph S. Friedman ,  John P. King ,  Joseph P. Pride, III

发明人： Joseph S. Friedman ,  John P. King ,  Joseph P. Pride, III

IPC分类号： G01S3/50

CPC分类号： G01S3/50

摘要： A direction finding method and apparatus for a radio signal source, modulated by a digital information signal and existing in a heavy interference environment, is based on cyclic crosscorrelation. The direction finding technique exploits the second order periodicity of a transmitted signal having digital modulation, whereby the technique is immune to narrow-band interference. Radio frequency signals are received by two spaced antennas, and the signal of interest can be considered as a cyclostationary process. The signal time of arrival difference between the two antennas is determined using a cyclic crosscorrelation method. This is implemented by sending the electrical signals, developed by the antennas, through a variable delay device, then to a balanced mixer. The composite signal from the mixer is sent to a band-pass filter whose center frequency is equal to the baud rate of the signal of interest. The output energy of the filter is proportional to that portion of the cyclic crosscorrelation function where the cyclic frequency corresponds to the baud rate. With the use of a peak detector, which finds the peak values of the cyclic crosscorrelation function, the time difference of arrival between the two antennas is determined. This, in turn, determines a line of position to the radio source.

摘要翻译： 用于由数字信息信号调制并且存在于严重干扰环境中的无线电信号源的测向方法和装置基于循环互相关。 方向发现技术利用具有数字调制的发送信号的二阶周期性，由此该技术不受窄带干扰的影响。 射频信号由两个间隔的天线接收，感兴趣的信号可以被认为是循环平稳过程。 使用循环互相关方法确定两个天线之间的信号到达时间差。 这是通过发送由天线开发的电信号通过可变延迟装置，然后发送到平衡混频器来实现的。 来自混频器的复合信号被发送到中心频率等于感兴趣信号的波特率的带通滤波器。 滤波器的输出能量与循环频率对应于波特率的循环互相关函数的那部分成正比。 利用寻找循环互相关函数的峰值的峰值检测器，确定两个天线之间的到达时间差。 这反过来又决定了无线电源的位置。