JPH04157383A - Measuring apparatus of azimuth - Google Patents

Abstract

PURPOSE:To enable simultaneous measurement of an incident angle with measurement of an azimuth by comparing phases of signals of one antenna element and the other antenna elements which are disposed at different positioned in the vertical direction. CONSTITUTION:Using antenna elements 1 and a nondirectional antenna element 2, an azimuth measuring apparatus 3 measures an azimuth angle. Signals from the elements 1 and 2 are inputted to an incident angle extracting element 4, a difference between phases of the signals of the two kinds of elements is taken by a difference circuit 42 and a phase shifter 41 is adjusted so that the difference be the minimum. Then the amount of shift at this time corresponds to a phase difference phi. When an incident angle obtained in the case when a radio wave is received from above with the elements 1 and 2 disposed linearly in the vertical direction is denoted by phi1, in other words, the phase difference phican be determined by an equation phi=2pid1.cosphi1/lambda (d1 denotes a vertical distance on a straight line between the elements 1 and 2, and lambda a wavelength). The incident angle phi1 can be measured from this phase difference phi.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention measures the direction of incoming radio waves by arranging a plurality of antenna elements at equal intervals on the circumference and scanning these antennas by sequentially switching them. This invention relates to a direction measuring device.

[Conventional technology]

As shown in FIG. 5, the conventional azimuth measuring device includes a circular array antenna in which a plurality of antenna elements 1 are arranged at equal intervals on the circumference, a non-directional antenna element 2, and a azimuth measuring device 3. It is configured.

The direction measuring device 3 performs scanning by sequentially electrically switching the antenna element 1 using a reference signal generator 36, and converts the frequency of the obtained signal into an IF signal using a frequency converter 31.
After passing through the sideband canceller 34, the direction measuring device 3
5. At this time, by switching and scanning the antenna element 1, a reception signal S1 whose reception phase changes in a sinusoidal manner as shown in FIG. A detected signal S,1 can be obtained. By comparing this signal with the reference signal S of the reference signal generator 36 as shown in FIG. 6(b), it becomes possible to measure the direction θ of the incoming signal.

In addition, the omnidirectional antenna element 2 is constantly receiving signals, and as shown in FIG. By inputting both the IF multiplied signal from 1 to the sideband canceller 34, unnecessary signals for direction measurement are removed.

In other words, as a result of receiving switching, the antenna element 1 contains a signal with the same component as this switching period (frequency),
If the original received signal contains a modulation component (especially an FM acid component) in the vicinity, it will interfere with the signal and cause an error in the direction measurement result.For this reason, the received signal including the direction signal,
By taking the difference between the received signal and the received signal that does not include the azimuth signal, the sideband canceller 34 extracts only the components necessary for azimuth measurement.

[Problem to be solved by the invention]

This conventional direction measuring device measures the direction of arrival of radio waves by processing signals received by both antennas: antenna elements 1 and omnidirectional antenna elements 20 arranged at equal intervals on the circumference. There is. For this reason, although it is possible to measure the plane azimuth angle, there is a problem in that the angle of incidence (elevation angle) of the radio waves cannot be measured.

An object of the present invention is to provide an azimuth measuring device that can measure the angle of incidence.

[Means for Solving the Problems] The direction measuring device of the present invention is capable of determining the phase of an incoming signal received by a negative antenna element, and the phase of an incoming signal received by another antenna element disposed at a position vertically different from this antenna element. It has means for comparing signal phases, and is configured to measure the azimuth and arrival angle of the arriving radio waves using this comparing means.

The comparison means is comprised of a difference circuit that takes the difference in phase difference between both antenna elements, and a phase shifter that controls one phase so that this difference is minimized.

[Effect]

According to the present invention, by utilizing the phase difference between the antenna elements disposed in the vertical direction, it is possible to measure the angle of incidence simultaneously with the measurement of the azimuth.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is an overall configuration diagram of the azimuth-window device of the present invention, and its antenna portion, as shown in FIG. 2, includes a plurality of antenna elements 1 arranged at equal intervals on the circumference, and these antenna elements
, and a non-directional antenna element 2 disposed at a position vertically different from each antenna element 1.

With this configuration, the conventional antenna configuration can be used as is.

The antenna element 1 and the antenna element 2 are connected to an azimuth measuring device 3 and an incident angle extracting section 4, respectively, which are constructed in the same manner as in the prior art. The angle of incidence extraction unit 4 includes a phase shifter 4 that shifts the phase of the signal from the antenna element 1, and an antenna element 2.
The processor 5 is configured to include a difference circuit 42 that calculates the phase difference between the two and the processor 5 to measure the angle of incidence based on this phase difference.

According to this configuration, the azimuth measuring device 3 can measure the azimuth using the antenna element 1 and the non-directional antenna element 2 in the same manner as in the past.

On the other hand, the angle of incidence extraction section 4 can measure the angle of incidence ψ based on the signals from the antenna elements 1 and 3. FIG. 3 is a diagram showing the principle, and for convenience of explanation, the antenna elements 1 and 2 are shown at the top.

It is arranged in a straight line below, and shows the state in which radio waves are received from above. If the angle of incidence in this case is φ, then the phase difference Δφ when receiving by antenna element 1 and antenna element 2 is as follows.

Note that d is the vertical distance between the antennas 1 and 2 on a straight line.

From this, if Δψ is found, the angle of incidence ψ can be measured.

That is, in the configuration of FIG. 1, both antenna elements 1.
2 is input to the incident angle extractor 4, the difference circuit 42 calculates the phase difference between the two signals, and the phase shifter 41 is adjusted so that the difference is minimized. The amount of displacement corresponds to Δψ.

Although the above embodiment shows an example in which the antenna element 1 and the antenna element 2 are located vertically on a straight line, in reality, the antenna element 1 and the antenna element 2 are located vertically on a straight line. Not yet. In this case as well, the angle of incidence can be measured in principle using the same method as described above. That is, as shown in FIG. 4, the received signal phase difference ψ between the antenna element 1 and the antenna element 2 can be determined from the following equation.

Note that is the horizontal distance between both antenna elements 1.2.

From this, the incident angle ψ2 can be measured by extracting ψ using the method explained in the above-mentioned principle.

〔Effect of the invention〕

As explained above, the present invention has the effect of being able to measure the angle of incidence at the same time as the azimuth measurement by comparing the phases of the signals of the antenna element and the other antenna elements arranged at different positions in the vertical direction. .

In addition, in the comparison means, by adjusting one phase using a phase shifter so that the difference between the signal phases of both antenna elements is minimized, the amount of displacement of the phase shifter at that time can be obtained as a phase difference. .

[Brief explanation of the drawing]

Fig. 1 is a block diagram of one embodiment of the direction measuring device of the present invention, Fig. 2 is a configuration diagram of the antenna part, Fig. 3 is a diagram for explaining the principle of measuring the angle of incidence, and Fig. 4 is different. Figure 5 is a block diagram of a conventional direction measuring device, and Figure 6 (
(a) and (b) are signal waveform diagrams when measuring the azimuth, respectively. 1.2...Antenna element, 3...Direction measuring device, 4.
...Incidence angle extraction unit, 5...Processor, 31.32...
Frequency converter, 33... Local oscillator, 34... Sideband canceller, 35... Direction measuring device, 36... Reference signal generator, 41... Phase shifter, 42... Differential circuit . Figure 1 Figure 3 Figure 4 σ2 Figure 6

Claims (1)

[Claims] 1. The direction of the incoming radio wave is determined based on the phase between adjacent antenna elements obtained by arranging a plurality of antenna elements at equal intervals on the circumference and electrically switching the antenna elements sequentially. The azimuth measuring device for measuring includes means for comparing the phase of an incoming signal received by the antenna element with the phase of an incoming signal received by another antenna element disposed at a position different from the antenna element in the vertical direction, An azimuth measuring device characterized by measuring the azimuth and the angle of incidence of incoming radio waves using comparison means. 2. Claim 1, wherein the comparison means is comprised of a difference circuit that takes the difference in phase difference between both antenna elements, and a phase shifter that controls the phase of one of the antennas so that this difference is minimized. The orientation measuring device described.