Direction finding
    1.
    发明授权
    Direction finding 失效
    方向发现

    公开(公告)号:US4639733A

    公开(公告)日:1987-01-27

    申请号:US609232

    申请日:1984-05-11

    IPC分类号: G01S3/48 G01S5/02

    CPC分类号: G01S3/48

    摘要: An interferometer type DF system uses an array of five antennas (A,B,C,D,E) arranged at the apices of a regular pentagon to define five wide apertures along the sides of the pentagon and a further five apertures along the diagonals. The phases of the signals received by each antenna, are measured modulo 2.pi. and processed to give a unique bearing of the radio source to the accuracy of the widest aperture defined by the array. One method of processing the phases is to calculate from them the Fourier coefficients of the Fourier series representing the spatial phase distribution. By comparing the difference between each calculated coefficient and a corresponding order coefficient of a set of imaginary antenna phases expressed as integral multiples of 2.pi., the complete 2.pi. phase differences between the measured phases modulo 2.pi. can be found. The bearing angle of the received signal is then the phase of the vector resulting from subtracting the first order Fourier coefficient of the integral phases from the calculated first order coefficient.

    摘要翻译: 干涉仪型DF系统使用布置在正五边形顶点的五根天线(A,B,C,D,E)的阵列,以沿着五边形的侧面限定五个宽的孔,以及沿对角线的另外五个孔。 由每个天线接收的信号的相位被模2 pi测量,并被处理以给予无线电源的独特的轴承以由阵列限定的最宽孔的精度。 处理相位的一种方法是从它们计算表示空间相位分布的傅里叶级数的傅立叶系数。 通过比较表示为2 pi的整数倍的一组虚拟天线相位的每个计算系数和相应的次序系数之间的差异,可以找到所测量的相位2 pi之间的完整2 pi相位差。 接收信号的方位角就是从计算出的一阶系数中减去积分相位的一阶傅里叶系数得到的向量的相位。

    Direction finding systems
    2.
    发明授权
    Direction finding systems 失效
    测向系统

    公开(公告)号:US4626859A

    公开(公告)日:1986-12-02

    申请号:US655637

    申请日:1984-09-28

    IPC分类号: G01S3/48 G01S5/04

    CPC分类号: G01S3/48

    摘要: A DF system using a circular array of three to eight antennas, analyses the received signals digitally by first calculating at (8) the Fourier transform of the received signals to obtain frequency information and deriving at (10) from the Fourier transform the relative phases of the received signals at each of a number of spaced sample frequencies. This phase information is then fed to a stage (12) which takes the spatial Fourier series of the phases from which the required bearing information is derived as .pi./2 minus the arctan of the ratio of the real and imaginary parts of the Fourier series taken to suitable moduli. For a four antenna array the diameter of the circular array is constrained to be less than half of the wavelength at the highest frequency of interest. For a three antenna array, the diameter is constrained to be less than one third the wavelength at the highest frequency of interest in order that the analysis should yield accurate and unambiguous bearing outputs.

    摘要翻译: 使用三到八个天线的圆阵列的DF系统,通过首先在(8)计算接收信号的傅立叶变换来数字地分析接收信号,以获得频率信息,并从(10)得到傅里叶变换的相对相位 在每个间隔采样频率的每一个处接收信号。 然后将该相位信息馈送到阶段(12),该阶段采用将所需轴承信息导出的相位的空间傅立叶级数作为pi / 2减去所采用的傅里叶级数的实部和虚部的比率的arctan 到合适的模量。 对于四个天线阵列,圆形阵列的直径被限制为小于感兴趣的最高频率的波长的一半。 对于三个天线阵列,直径被限制在小于感兴趣的最高频率波长的三分之一,以便分析应该产生精确和明确的轴承输出。