JPH05302969A - Radio-wave direction measuring instrument - Google Patents

Abstract

PURPOSE:To obtain a radio-wave direction measuring instrument wherein it does not contain any mechanically movable part and its constitution is simple and low-cost. CONSTITUTION:The following are arranged nearly on the same axis: two directional antennas 1, 2 which are provided with the same already known reception directivity characteristic; and a non-directional dipole antenna 3. The directivity of the directional antennas 1, 2 is former to be symmetric with respect to the horizontal plane and to be superposed partly. Reception inputs from the individual antennas are received, amplified and digitally converted respectively by means of receivers 4, 5, 6 and A/D converters 7, 8, 9. A ROM 11 stores the distance-to-reception level characteristic data on the dipole antenna 3 and the reception level-to-azimuth characteristic data on the individual antennas 1, 2. A CPU 11 measures the direction of incoming radio waves on the basis of the stored data in the ROM 11 and reception levels by means of the three antennas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave direction measuring instrument,
In particular, the present invention relates to a radio wave direction measuring instrument that measures the direction of incoming radio waves to detect the direction.

[0002]

2. Description of the Related Art Conventionally, this type of radio azimuth measuring device includes a Koni-Cal scan system for mechanically rotating a radio beam to detect a direction, a beam switch system for detecting a direction by switching a radio beam with a relay or the like. A typical example is a monopulse system in which a plurality of beams are formed at the same time without changing the directions of the antenna beams and an angular error is detected by a 1-bit pulse.

[0003]

The conventional direction finding method described above has a mechanically movable portion in the conical scan method and the beam switch method, and has a difficulty in durability. Further, the monopulse system has no mechanically movable parts, but has a problem in that it is difficult in terms of price.

The object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide an inexpensive radio wave direction finder having a simple structure, which has no mechanically movable parts and has increased durability.

[0005]

A radio wave azimuth measuring device of the present invention is a radio wave azimuth measuring device for measuring the azimuth of an incoming radio wave, and includes an omnidirectional first azimuth receiving pattern formed by a dipole antenna, A second azimuth receiving pattern and a third azimuth receiving pattern of known directivity formed by superposing a part of the two directional antennas arranged on the same axis as the dipole antenna; The distance to the source of the incoming radio wave obtained based on the reception level according to the azimuth reception pattern, the reception level of the incoming radio wave according to the first, second, and third azimuth reception patterns, and the predetermined values of the two directional antennas. The configuration is such that the azimuth of the incoming radio wave is obtained based on the reception level vs. azimuth angle characteristic previously obtained at the distance of.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention.

The embodiment shown in FIG. 1 exemplifies a case where two identical directional antennas having known directivities are used.
Directional antenna 1 and directional antenna 2 having equal azimuth receiving patterns, dipole antenna 3 having omnidirectional azimuth receiving patterns, receivers 4, 5 and 6 for receiving and amplifying respective antenna outputs, and receivers. A / D converters 7, 8 and 9 for digitizing the outputs of 4, 5, and 6, a CPU 10 for calculating the arrival direction, a ROM 11 for storing data necessary for calculating the arrival direction, and an output for outputting the calculated direction. 1, and the bus line 13 is also shown in FIG.

Next, the operation of this embodiment will be described.
FIG. 2 is a diagram showing an azimuth reception pattern in this embodiment.

In FIG. 2, the second azimuth receiving pattern 1
01 and the third azimuth receiving pattern 201 show the same azimuth receiving directional pattern formed by the directional antenna 1 and the directional antenna 2, respectively, and the third azimuth receiving pattern 301 shows the dipole antenna 3 3 shows an azimuth omnidirectional reception pattern by.

The directional antennas 1 and 2 are arranged on the same axis including the dipole antenna 3, and the azimuth receiving patterns formed are symmetrical to each other in the azimuth plane, that is, the horizontal plane, and partially overlap each other. It

Now, it is assumed that the incoming radio wave L comes from the direction shown by the arrow. This conventional radio wave is received at point A according to the omnidirectional first azimuth receiving pattern 301, point B according to the second azimuth receiving pattern 101, and point C according to the third azimuth receiving pattern 201. With sensitivity, it is received by each antenna.

The outputs of these antennas are respectively the receiver 4 and the A / D converter 7 shown in FIG.
The A / D converter 8 and the receiver 6 and the A / D converter 9 receive and amplify the signals, and digitally convert them.

The ROM 11 preliminarily measures the relation between the azimuth angle and the reception level at a predetermined distance by the directional antenna 1 and the directional antenna 2 and the relation between the reception level and the distance by the dipole antenna 3. Stored data and

FIG. 3 is a reception level vs. distance characteristic diagram of the dipole antenna 3. The vertical axis represents the reception level, the horizontal axis represents the distance, and the level (intensity) value is expressed as a normalized value with the level at 100 km as 1.

FIG. 4 shows a predetermined distance, 10 k in this embodiment.
FIG. 7 is a characteristic diagram of reception level versus azimuth angle by the first and second directional antennas at m. Also in FIG. 4, the reception level is represented by a normalized value with the reception level at a predetermined azimuth angle being 1.

It should be noted that the right side (+ side) and the left side (-) symmetrical with respect to the directional centers of the second and third azimuth receiving patterns.
Side) has the same properties.

The CPU 10 knows that the distance is 70 km if the input level at the point A by the dipole antenna 3 is level 3 by collating with the data of FIG. 3 stored in the ROM 11, for example.

Next, the CPU 10 determines which directional antenna is used for the right side (+ side) or the left side (-side) of the directional pattern.
The number of times is calculated using the data stored in the ROM 11 as follows.

First, the reception level is converted by the following equation (1). Reception level at point B × (reception level of dipole antenna 3 at 10 km = 6) / (reception level of dipole antenna 3 at 70 km = 3) (1) What is meant by equation (1) is at point B When the azimuth angle is obtained from the reception level by using the relationship between the azimuth angle and the reception level in FIG. 4, the relationship in FIG. 4 is at 10 km. Therefore, the distance 70 km to the transmission source of the incoming radio wave is 10 km.
The correction is performed by converting the data into the distance correspondence data of m.

By this conversion correction, point B, that is, the first point
The arrival azimuth by the directional antenna of is obtained from the data of FIG. 4 stored in the ROM 11.

However, there are two such azimuths, the point B and the point (B) symmetrical with the point B with respect to the directional center. Therefore, in this case, it is determined as follows that the desired arrival direction is not the point (B) but the direction including the point B.

Similarly, the CPU 10 obtains the azimuth angle for the reception level at the point C by the directional antenna 2. In this case as well, two azimuth angles of the + side and the − side are obtained, but it is determined that the azimuth angle that is the same as that of the directional antenna 1 is the desired azimuth angle, and the determination result is output from the output unit 12. To be done.

In this way, it is possible to eliminate the mechanically movable part and calculate the arrival direction of the radio wave with a simple structure.

In the above-described embodiment, the two directional antennas have the same characteristics, but even if the two directional antennas have different characteristics, their respective reception level-azimuth angle characteristics are measured in advance at a predetermined distance and stored in the ROM 11. Obviously, it can be easily carried out by placing it.

[0025]

As described above, according to the present invention, a non-directional reception pattern by a dipole antenna and a pair of left and right directional antennas symmetrically arranged with the axis of the dipole antenna partially overlap. Arriving radio waves are received by a pair of symmetrically formed azimuth receiving patterns, and the arriving azimuth is based on the reception level and the dipole antenna distance vs. reception level and the directional antenna azimuth angle vs. reception level acquired in advance. By knowing, there is an effect that it is possible to realize a simple and inexpensive radio wave direction measuring instrument in which mechanically movable parts are unnecessary and durability is remarkably increased.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing a direction reception pattern in FIG.

3 is a reception level vs. distance characteristic diagram of the dipole antenna 3 in FIG.

FIG. 4 is a reception level vs. azimuth angle characteristic diagram of the first and second directional antennas 1 and 2 in FIG.

[Explanation of symbols]

 1 1st directional antenna 2 2nd directional antenna 3 dipole antenna 4,5,6 receiver 7,8,9 A / D converter 10 CPU 11 ROM 12 output part 101,201,301 direction reception pattern

Claims (1)

[Claims] 1. A radio wave azimuth measuring device for measuring the azimuth of an incoming radio wave, comprising an omnidirectional first azimuth receiving pattern formed by a dipole antenna, and two directional patterns arranged on the same axis as the dipole antenna. Radio wave having a known directional second azimuth reception pattern and a third azimuth reception pattern formed by superimposing a part of the directional antenna, and arriving radio wave obtained based on the reception level of the first azimuth reception pattern. To the transmission source, the reception level of the incoming radio wave by the first, second and third azimuth reception patterns, and the reception level vs. azimuth angle characteristic obtained in advance at a predetermined distance of the two directional antennas. A radio wave azimuth measuring device characterized by finding the azimuth of incoming radio waves based on