JPH0261576A - Phase difference direction finder - Google Patents

Abstract

PURPOSE:To calculate an angle of incidence of a incoming radio wave without information on frequency by arranging two sets of antennas at a specified angle to perform an arithmetic processing of a phase difference separately between both the antenna groups. CONSTITUTION:A phase discriminator 4a detects a phase difference phi1 between signals passing through receivers 2a and 2b after received with antennas 1a and 1b and likewise, a phase discriminator 4b detects a phase difference phi2 between signals passing through receivers 2c and 2d after received with antennas 1c and 1d. Here, the phase difference phi1 and phi2 shall be cleared of periodicity thereof. Then, when the phase differences phi1 and phi2 and antenna intervals d1 and d2 are inputted into an arithmetic processor 5, the processor 5 can calculate an angle theta of incidence even with the absence of information on frequency based on a specified formula.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device that passively detects the arrival direction of radio waves such as radar waves, and in particular performs phase difference direction detection instantaneously and precisely without frequency information. It is related to the device.

[Conventional technology]

Figure 4 shows, for example, Penisiche, Uwo Publishing (P
James B, Ts published by ENINSULA PUBLISHING
The document “Microwave Regivers and Retired Components J (M
icrowave Receivers and Re
In Figure 0, which is a phase difference direction finding device shown in 1ated Components), la and lb are antennas,
2a and 2b are receivers that amplify radio waves received by this antenna, and 3 is this receiver 2a.

This is a mixer that detects the phase difference between the signals from 2b.

Next, the operation will be explained. When radio waves arrive at an angle of θ to antennas la and 1b, receivers 2a and 2b
The phase difference φ between the signals obtained from is determined by λ. However, the wavelength of the incident wave is λ, and the antenna la
, lb is the interval d. The mixer 3 is a device that detects this phase difference φ. From the phase difference φ obtained by this mixer 3, the incident angle θ can be determined as 2 πd.

[Problem that the invention attempts to solve]

Since the conventional phase difference direction finding device is configured as described above, there is a problem in that it is impossible to calculate the angle of incidence θ unless information on the wavelength, that is, the frequency, is obtained from another measurement system.

This invention was made in order to solve the above-mentioned problems with the conventional ones, and its purpose is to obtain a phase difference direction finding device that can obtain the angle of incidence θ without requiring frequency information. do.

[Means to solve the problem]

The phase difference direction finding device according to the present invention is configured such that two antenna groups are arranged at a predetermined angle, and the angle of incidence of an incoming radio wave is determined based on the phase difference between the antenna groups.

[Operation] In this invention, the phase difference direction finding device calculates the phase difference between the two sets of antenna groups, so the frequency information of each set cancels each other out, and therefore there is no frequency information. The angle of incidence of the incoming radio wave can be calculated.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows a phase difference direction finding device according to an embodiment of the present invention, and in the figure, la, lb, lc, 1d are antennas, 2a,
2b, 2c, 2d are receivers that amplify the signals received by each of these antennas, 4a, 4b are 2a,
This is a phase discriminator that detects the phase difference between 2b and 2c + 2d, and outputs a phase difference without periodicity. 5 is a phase discriminator and an arithmetic processor for calculating θ which calculates the angle of incidence from the phase difference between 4a and 4b.

Next, the operation will be explained. The phase difference between the signals received by antennas 1a and 1b and passed through receivers 2a and 'lb is detected by phase discriminator 4a. However, the periodicity of this phase difference must be removed by some means.

The relationship between this phase difference φ and the incident angle θ is given by: Similarly, the relationship between the phase difference between the antennas lc and ld and θ is expressed as follows. By dividing equation (3) by equation (4), θ can be found using equation (3). The arithmetic processor 5 for calculating θ is (
5) This device calculates the antenna spacing d, dt and its phase difference φ1... even without wavelength information. The incident angle θ can be determined from φ2.

Although the above embodiment shows the case where the angle formed by the antenna group is 90°, other angles α may be used as shown in FIG. 2. In FIG. 2, the device configuration is the same as in FIG. 1. However, the calculation in the calculation processor 5 for calculating θ is φ, d! The process changes to the process of finding θ that satisfies sin θ φz d+ 5in (θ+α).

Further, in FIG. 3, three antenna groups are arranged orthogonally to each other so that not only the horizontal direction but also the vertical direction incident angle can be determined at the same time.

In FIG. 3, le and If are antennas for vertical direction measurement, 2e and 2f are receivers for these antennas, 4C is a phase discriminator, and 5 is an arithmetic processor for calculating θ. The operation in the vertical direction is similar to that in FIG. In this case, originally 4
Where two sets of antenna groups are required, one set is shared by taking advantage of the fact that the antenna groups are orthogonal, which has the effect of reducing the number of antennas.

〔Effect of the invention〕

As described above, the phase difference direction finding device according to the present invention is configured so that direction finding can be performed by phase difference without frequency information, so a frequency measurement means is not required, and therefore the configuration is simpler. This has the effect of making highly accurate direction finding possible instantaneously.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a phase difference direction finding device according to one embodiment of the present invention, FIGS. 2 and 3 are block diagrams showing a phase difference direction finding device according to another embodiment of the present invention, and FIG. FIG. 1 is a configuration diagram showing a conventional phase difference direction finding device. In the figure, 1 is an antenna, 2 is a receiver, 3 is a mixer,
4 is a phase discriminator, and 5 is an arithmetic processor for calculating θ.

Claims (1)

[Claims] (1) In a direction finding device that measures the angle of incidence of incoming radio waves based on the phase difference between the antennas, two sets of antenna groups are arranged at a predetermined angle to each other, and the respective positions of the two sets of antenna groups are measured. A phase difference direction finding device comprising: means for measuring a phase difference; and arithmetic processing means for determining an angle of incidence from two phase differences obtained by this means.