JPS5951371A - Antenna - Google Patents

Abstract

PURPOSE:To detect the coming direction of radio waves quickly with limited processing circuits by determining the direction of coming radio waves based on the combination of Fourier transform values of signals separately received with the antenna arrays. CONSTITUTION:A plurality of coming radio waves, for example, two are received with linear array antennas 2a-2c and processed with a Fourier transform section of corresponding angle computing units 3a-3c to detect the conic angles of a cone with the array axis of antennas 2a-2c and the direction of coming radio waves. The direction of radio waves is determined with direction detection circuits 4d, 4e depending on the combination thereof. Based on the combination, directions of coming radio waves is calculated through a calculation circuit 5. With such an arrangement, directions of coming radio waves are detected quickly with limited processing circuits.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antenna device that detects the arrival direction of a plurality of radio waves when they arrive.

Conventional devices of this type perform beam scanning to detect the direction of incoming radio waves. According to this method.

There was a problem in that high-speed processing was difficult because the beam had to be scanned over the entire coverage area. In addition, the received signal from the element antenna of the linear array antenna is Fourier transformed using an FFT circuit, and the angle? There is also a method of calculating it, but in this case, when performing spatial bell scanning, a two-dimensional Fourier transform must be performed.

A total number of FFT circuits are required.

In order to eliminate these drawbacks, this invention provides 771 circuits in three linear array antennas that are not parallel to each other.
A 771 circuit is connected to each linear array antenna to detect the angle between the direction of the incoming radio wave and each linear array antenna.The angle detected by the first linear array antenna and the angle detected by the second linear array antenna are A three-dimensional direction angle is calculated by combining the angles obtained one by one. However, when there are multiple arriving radio waves, extra angles are calculated in addition to the true angle of arrival. Therefore.

Next, the total direction angle is calculated by combining the angles detected by the second linear array antenna and the third linear array antenna one by one. The arrival angle of the radio wave is defined as the angle of arrival of the radio wave that is commonly included in the direction angle calculated by the combination of this direction angle and the first linear array antenna and the second linear array antenna. The goal is to detect the direction of arrival of radio waves. The drawings will be explained in detail below.

Figure 1 shows examples of this invention (Ia) and (Ib).
, (Ic) barbed element antenna, (2a) linear array antenna composed of H element antenna (1a), (2b)
) Linear array antenna composed of U element antenna (1b), (2c) linear array antenna composed of element antenna (1C), (3a), (3b) t
- is an angle calculation circuit, (4d) and (4e) are direction detection circuits, and (51t'l calculation circuit).

Next, the operation of this embodiment will be described. Angle calculation circuit (3a
), (3b), and (3c) are the received signals from the element antennas of linear array antennas (2a), (2b), and (2c), which are Fourier-transformed using an IFFT circuit, and the incoming radio waves and the elements of each linear array antenna are Calculate the angle between the antenna and the array axis. Figure 2 is a diagram showing a cone with the linear array antenna as the axis and the above angle as the cone angle. indicates the angle calculated by the angle calculation circuit. Now consider the case where there are two arriving radio waves. The angle calculated by the angle calculation circuit (3a) is converted to 1. ψa2. Angle calculation circuit (31-+
) are calculated as ψb+ and ψb2. Direction detection circuit (4d,) U combination of two angles (ψafi
, ψbj) (1-j=' $ 2), four direction angles are detected, of which two are true direction angles of radio waves, and the remaining two need to be removed. Next, in the same way, the angle calculated by the angle calculation circuit (3C) is ψ. 1. ψ. 2
, the direction detection circuit (4e) detects four direction angles by the combination of two angles (ψbi, ψ.j) (i, j21.2). The calculation circuit (51) detects the direction angle among these four direction angles that is commonly included in the direction angle detected by the combination of (ψaimψ1.j) and detects the arrival direction of the radio wave. This is a diagram showing a cone with the linear array antenna as the axis and the above angle as the cone angle, and the direction of the incoming radio wave is indicated by the generatrix on this cone surface. Shows the calculated angle.

Figure 3 is a diagram showing the above operation.

Lb and Lc are angle calculation circuits (3a), (3b),
A straight line representing the set of angles detected in (3c), ψa1. ψa2 is the angle detected by the angle calculation circuit (3a) when radio waves arrive from two directions, ψb
l, ψb2 is the angle, ψ, detected by the angle calculation circuit (3b). 1°ψc2 is the angle detected by the angle calculation circuit (3C), the black circle is a point indicating the arrival direction of the radio wave, and the white circle is a point indicating the angle detected in excess. According to the operation shown in the embodiment of FIG. 1, ψaimψbi−ψci (i=1
Lai, Lbi, Lci dropped off at e2)
(i = 1, 2) The direction angle found from the point where the perpendicular lines intersect is calculated by the direction detection circuit (4d), (4θ), but the direction detection circuit (4(1), (4θ) is included in common Calculating the angle by the calculation circuit (5) corresponds to calculating the point where the three perpendicular lines intersect as shown in FIG. 2, and only the direction of arrival of the radio waves can be detected.

Although the above description has been made regarding the case where radio waves arrive from two directions, the present invention is not limited to this, and can be used in cases where a larger number of radio waves arrive.

As described above, the antenna device according to the present invention has the advantage that the arrival directions of a large number of radio waves can be detected by a simple processing circuit.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing a cone whose axis is the arrangement axis of the linear array antenna, and the cone angle is the angle calculated by the angle calculation circuit, and Fig. 3 is a diagram showing the detection (Ia) in Figure 1 shows a diagram of the angle
(1b), (1c) H element antenna. (2a) Near array antenna consisting of LD element antenna (1a), (2b) U element antenna (1b)
A linear array antenna consisting of (2c) a U element antenna (1C) +
(3a) *(3b), (6c) are angle calculation circuit 1
(4d), (4e) are direction detection circuits, (5) ii calculation circuit, Lii linear array antenna, ψ is the angle calculated by the above calculation circuit, and La. Lb, Lci4 angle calculation circuit (3aL (3b), p
A straight line representing a set of angles detected in c), cage 1. ψa2
is the angle detected by the angle calculation circuit (3a), ψb1. ψ
b2 is the angle detected by the angle calculation circuit (3b), ψc1
．． ψc2 is the angle detected by the angle calculation circuit (3c), the black circle is a point indicating the arrival direction of the radio wave, and the white circle is a point indicating the angle detected in excess. In addition, the same or equivalent parts in the figures have the same reference numerals in Figure 1.

Claims (1)

[Claims] A plurality of element antennas are arranged on three straight lines that are not parallel to each other. A second and a third linear array antenna are formed, and the element antenna array axis of each linear array antenna is applied to each of the three linear array antennas by Fourier transforming the received signal of the element antenna of the linear array antenna. The first step is to calculate the angle between the direction of the incoming radio wave and the direction of the arriving radio wave. second and third angle calculation circuits are provided, and a plurality of first angle calculation circuits are provided, the element antenna array axis of the first linear array antenna is the axis, and the angle calculated by the first angle calculation circuit is a cone angle. and the second conical surface of
Direction detection for determining a plurality of first directional angles where a plurality of second conical surfaces intersect, with the array axis of the linear array antenna as the axis and the conical angle being the angle calculated by the second angle calculation circuit. a circuit is provided, and a number of third conical surfaces whose cone angle is an angle calculated by the third angle calculation circuit and whose axis is the arrangement axis of the third linear array antenna, and the second conical Determining that a plurality of second direction angles where the surfaces intersect are determined by using the direction detection circuit and another direction detection circuit, and an arrival angle at which the first direction angle and the second direction angle coincide is calculated. An antenna device characterized by being provided with a circuit.