JPS6015030B2 - Direction measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a direction measuring device in a radio direction finder.

[Prior Art] A conventional direction measuring device of this type is shown in FIG.

In the figure, 1 is an antenna for vertically polarized wave reception, 2 is a sense antenna, 3 is an azimuth measuring receiver, and 7 is an output terminal. Next, the operation will be explained.

A vertically polarized signal emitted from a moving object is transmitted to the antenna 1
and sent to the orientation receiver 3 for processing.

Further, the signal from the sense antenna 2 is sent to the direction measurement receiver 3 as a reference signal. This direction measuring receiver 3 outputs the arrival direction of radio waves using the signal from the sense antenna 2 and the signal from the antenna 1. The reason why vertically polarized waves are used to measure direction in this way is that the radio equipment of a moving object such as a taxi generally emits radio waves from an antenna that transmits vertically polarized waves. [Problems to be Solved by the Invention] However, in conventional direction measuring devices using only vertically polarized waves, radio waves may be refracted or reflected by undulating terrain, such as mountains and valleys, or terrain with oceans and rivers. occurs,
The measurement results sometimes differed greatly from the true radio wave emission direction.

This invention was made in order to eliminate the drawbacks of the conventional methods as described above, and it also measures the electric field strength and direction in the horizontal polarization plane, and separates the measured values in the vertical polarization plane and the measured values in the horizontal polarization plane. The object of the present invention is to provide a device that can correct the radio wave direction based on the relative value of .

[Means for solving problems]

A direction measuring device according to the present invention receives radio waves emitted from an antenna for transmitting vertically polarized waves of an object whose direction is to be measured, and measures the electric field strength and direction of the vertically polarized wave plane of the radio waves. A receiver, a horizontal polarization receiver that measures the electric field strength and direction of the horizontal polarization plane of the radio wave, and a ratio of the electric field strength of the vertical polarization plane and the electric field strength of the horizontal polarization plane measured by each of the above receivers. By comparing with a predetermined value,
and azimuth correction means for correcting the azimuth determined by the measurement on the direct polarization plane.

[Effect]

When the radio waves emitted from the vertically polarized antenna 1 of an object are directly received, the electric field strength on the vertical polarization plane is much larger than the electric field strength on the horizontal polarization plane. When the signal is received after being reflected, the difference in electric field strength between the vertical polarization plane and the horizontal polarization plane is small.

Therefore, according to the configuration of the present invention, the azimuth correction means compares the ratio of the electric field strength on the vertical polarization plane and the electric field strength on the horizontal polarization plane with a predetermined value to correct the azimuth measured on the vertical polarization plane. , an orientation for which the ratio is larger than a predetermined value can be obtained as the true orientation. [Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

Figure 2 shows this system diagram, where 1 is an antenna for direct polarization transmission, 2 is a sense antenna, 3 is a vertical direction measurement receiver,
4 is an antenna for horizontal polarization reception, 5 is a horizontal polarization receiver, 6
7 indicates an azimuth correction circuit (azimuth correction means) and an output terminal.

When the radio waves emitted from the vertically polarized wave transmitting antenna of the object whose direction is to be measured arrive at the antenna on the receiving side, the vertically polarized wave component of the arriving radio wave is transmitted to the antenna 1 for vertically polarized wave receiving. and is sent to the direction measurement receiver 3 via the sense antenna 2.

In this direction measurement receiver 3, the electric field strength of the vertically polarized wave plane of the radio wave is measured from the radio wave captured by the sense antenna 2, and the field strength is also captured by the sense antenna 2 and the antenna 1 for vertical polarization reception. By comparing the phases of the radio waves, the direction of the radio waves is measured, and such a direction measuring receiver 3 is widely known as a general receiver. The horizontally polarized wave component is sent from the horizontally polarized wave receiving antenna 4 to the horizontally polarized wave receiver 5.

In this horizontally polarized receiver 5, an antenna 4 for receiving horizontally polarized waves
The electric field strength of the horizontally polarized wave plane of this radio wave is measured from the radio wave captured by the horizontally polarized wave receiving antenna 4.
By rotating the device in a horizontal plane, the electric field strength in all directions is measured and compared, and the direction with a relatively large electric field strength is detected as the arrival direction of the radio waves. Such a horizontally polarized receiver 5 is also widely known as a general receiver. The output data of the two receivers 3 and 5 are sent to the azimuth correction circuit 6, and the electric field strength of the Chinese polarization plane and the electric field strength of the horizontal polarization plane in the azimuth output from each receiver 3 and 5 are compared. , corrects the azimuth data output from the azimuth measurement receiver 3, and outputs the corrected azimuth data to the output terminal 7.
Output to.

For example, if a radio wave emitted from an antenna for transmitting vertically polarized waves of an object arrives directly to each antenna 1, 2, and 4, but it is reflected by a nearby mountain and arrives at antenna 1, 2, and 4, the upper direction The measurement receiver 3 receives the Chinese polarization component of the radio wave and receives data indicating that a large electric field strength exists in the direction A of the direct radio wave and the direction B of the reflected indirect radio wave. Output.

In other words, two directions A and B are output. However, when radio waves are emitted from an antenna for transmitting vertically polarized waves from an object, the electric field strength on the vertically polarized wave plane is much larger than that on the horizontal polarized wave plane when there is no reflection, but the electric waves are reflected by mountains. As a result, the plane of polarization changes, and the difference in electric field strength between the vertical and horizontal polarization planes becomes extremely small by 4.

Strictly speaking, this difference is a ratio of electric field strengths, since electric field strengths are expressed in decibels (dB). Therefore,
The direction correction circuit 6 sets a predetermined value to a value slightly larger than the standard ratio of the electric field strength in the vertical polarization plane and the electric field strength in the horizontal polarization plane for radio waves without reflection.
This azimuth correction circuit 6 sets both the above azimuth A.
, B is compared with the above predetermined value, and the direction A in which the difference between the above electric field strength ratio and the predetermined value is small is the true direction, and the above ratio is It is determined that the azimuth B with a large difference from the predetermined value is a false azimuth, and the true azimuth A is outputted to the output terminal 7 as azimuth data.

Note that the electric field strength of the received radio wave changes depending on the transmission output, distance, etc. of the object receiving the radio wave.

For example, the smaller the transmission output, the lower the field strength of the received radio waves by 4. However, the ratio of the electric field strengths of vertically polarized waves and horizontally polarized waves has nothing to do with the transmission output. Furthermore, the farther the object is, the more the radio waves are attenuated and the electric field strength becomes smaller. However, since both vertically polarized waves and horizontally polarized waves are attenuated at the same rate, if we take the ratio of the two, this ratio will be independent of distance. Therefore, according to the present invention, the orientation of an object can be obtained with high accuracy regardless of the transmission output and distance of the object. [Effects of the Invention] As described above, according to the present invention, the azimuth measured on the vertical polarization plane is corrected based on the deviation of the data measured on the horizontal polarization plane, so the accuracy of azimuth measurement is significantly improved. It has the effect of

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a conventional direction measuring device, and FIG. 2 is a system diagram showing a direction measuring device according to an embodiment of the present invention. 1...Antenna for vertical bridge wave reception, 2...Sense antenna, 3...Azimuth measurement receiver, 4...Antenna for horizontal polarization reception, 5... ...Horizontal polarization receiver, 6...Azimuth correction circuit. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Figure 1 Figure 2

Claims (1)

[Claims] 1. An azimuth measurement receiver that receives radio waves emitted from an antenna for transmitting vertically polarized waves of an object whose azimuth is to be measured, and measures the electric field strength and azimuth of the vertical polarization plane of the radio waves, and A horizontal polarization receiver measures the electric field strength and direction of the wave surface, and by comparing the ratio of the electric field strength of the vertical polarization plane and the electric field strength of the horizontal polarization plane measured by each of the above receivers with a predetermined value, An azimuth measuring device comprising azimuth correction means for correcting azimuth based on measurements on the polarization plane.