JPH0421828B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a device for measuring the direction of incoming radio waves.

[Technical background of the invention and its problems]

Conventionally, in order to measure the direction of incoming radio waves, the output signal of a goniometer is demodulated by a receiver, and this demodulated output signal is displayed on a display so that an operator can determine the direction. That is, the azimuth waveform output from the receiver is, for example, a signal as shown by the dashed line 11 in FIG. 1, and this signal is supplied to an analog/digital conversion circuit and quantized for each predetermined azimuth angle. . This quantized signal is displayed on the display as azimuth waveform data 12 corresponding to the azimuth, as shown in FIG. Further, at this time, a portion of the azimuth waveform data 12 located in the radio wave arrival direction (the portion indicated by a dotted circle in the figure) is displayed enlarged several times so that the azimuth waveform data 12 can be easily viewed. At this time, on the right side of the azimuth waveform data 12 in the figure, a number of data of the same level corresponding to the magnification ratio are displayed simultaneously, and each azimuth waveform data 12 itself is also displayed in an enlarged manner. This azimuth waveform data 12 is visually viewed by the operator on a display, and the azimuth angle D corresponding to the lowest level of the azimuth waveform is read to measure the arrival direction of the radio wave. Therefore, this arrival method relies on the operator's visual measurement for the final azimuth measurement, which can lead to large measurement errors if the signal is poor due to interference, etc., and also makes it difficult to perform quick measurements. It has disadvantages such as being difficult.

[Purpose of the invention]

This invention was made based on the above circumstances, and its purpose is to shorten measurement time and improve measurement accuracy by determining the direction of arrival of radio waves by calculation rather than by visual estimation by the operator. The aim is to provide a direction measuring device that can

[Summary of the invention]

This invention applies to any two slopes of both slopes adjacent to the radio wave arrival direction of the azimuth waveform data displayed on the display.
Each point is sequentially specified using a cursor line, two straight lines including each of these two points are found, and the direction is automatically found from the intersection of these straight lines.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In FIG. 2, as in the prior art, an azimuth versus level signal is extracted from radio waves received by a goniometer. The quantized azimuth waveform data 21 obtained by quantizing this azimuth angle vs. level signal is the position coordinate of the display screen (azimuth vs. level: Normally, the goniometer output has a sum beam and a difference beam, and the sum beam has a beam direction direction. The level is stored in the display memory 22 in correspondence with the point where the level reaches a peak at , and the difference beam has a null in the beam direction as shown in FIG. This stored azimuth waveform data is sequentially read out, enlarged to a desired magnification, and displayed on the display 23. The display 23 displays azimuth waveform data 21 as shown in FIG. For convenience of explanation, the upward waveform data 21 is shown as a straight line.

On the other hand, 24 is a cursor generation circuit. This cursor generation circuit 24 displays a third cursor on the screen of the display 23.
Cursor line C perpendicular to the azimuth direction as shown in the figure
is displayed. This cursor line C can be moved in the azimuth direction within the screen of the display 23 by operating an operator provided in the cursor generation circuit 24. When point a, for example, in 21 is designated, the position of this cursor line on the screen is read by a cursor position reader 26 and supplied to an azimuth/inclination angle calculator 27. Note that the azimuth waveform data specified by the cursor line is the left end of each data in the diagram because the data is enlarged. In the azimuth/inclination angle calculator 27, position coordinates corresponding to point a and 2 to 3 azimuth waveform data located in the vicinity thereof are fetched from the display memory 22 from the supplied position data of the cursor line, and A straight line connecting these data including the points is approximated. Similarly, when point b is specified using the cursor line C, the position of this cursor line is read by the cursor position reader 26 and supplied to the azimuth and inclination angle calculator 27 . In this azimuth/inclination angle calculator 27, from the supplied position data of the cursor line, position coordinates corresponding to point b and two to three pieces of azimuth waveform data located in the vicinity thereof are taken in from the display memory 22, and
A straight line connecting these data including the points is approximated. The data of the two straight lines obtained in this way is supplied to the intersection point calculator 28, and the intersection point of these straight lines is determined in this calculator 28. The data of this intersection is converted into azimuth data via a memory table constituted by, for example, a ROM (read-only memory). That is, the data of the intersection point is used as an address in the ROM, and azimuth character data is stored in correspondence with this address, and the corresponding azimuth character data is read out by specifying the address using the data of the intersection point. being done. This read azimuth character data is supplied to the display 23 and displayed as characters, for example, at the corners of the screen.

According to the above configuration, arbitrary points on both slopes adjacent to the lowest level of the azimuth waveform data quantized and displayed on the display 23 are specified by the cursor line, and the specified arbitrary points and this Both slopes are approximated by two straight lines from azimuth waveform data close to , and the arrival direction of the radio wave is automatically determined from the intersection of these straight lines. Therefore, the accuracy of measurement can be improved compared to the case where the operator visually measures the arrival direction.

Furthermore, since the direction of arrival can be immediately determined by simply aligning the cursor line with an arbitrary point on the displayed azimuth waveform data, it is possible to shorten the measurement time.

In the above embodiment, the azimuth waveform data is displayed so that the direction of arrival of the radio wave is at the lowest level, but this is not limited to this, and the same applies even when the azimuth waveform data is displayed so that the direction of arrival of the radio wave is at the highest level. It is possible to implement it.

It goes without saying that various other modifications can be made without departing from the gist of the invention.

〔Effect of the invention〕

As described in detail above, according to the present invention, there is provided an azimuth measuring device that can shorten measurement time and improve measurement accuracy by determining the direction of arrival of radio waves through calculation rather than visual measurement by the operator. Can be provided.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining a conventional direction measuring method, FIG. 2 is a configuration diagram showing an embodiment of a direction measuring device according to the present invention, and FIG. 3 is a diagram for explaining the operation of FIG. 2. FIG. 21...Azimuth waveform data, 22...Display memory, 23...Display device, 24...Cursor generation circuit, 26...Cursor position reader, 27...Azimuth inclination angle calculator, 28...Intersection point calculator, C...Cursor line.

Claims (1)

[Scope of Claims] 1. A means for extracting an azimuth versus level signal from radio waves received by a goniometer; a circuit for quantizing the azimuth versus level signal extracted by this means and outputting it as azimuth waveform data; a memory for storing the azimuth waveform data; a display for displaying the azimuth waveform data read from the memory; a circuit for generating a cursor line on a display screen of the display; and a circuit for displaying the cursor line on the display. means for individually matching the azimuth waveform data on both slopes adjacent to the direction of arrival of the radio waves among the azimuth waveform data obtained, a reader for reading the position of the cursor line, and a cursor line read by the reader. means for reading the azimuth waveform data specified by the cursor line and the azimuth waveform data adjacent thereto from the memory; What is claimed is: 1. An azimuth measuring device comprising: a circuit for approximating the approximated straight lines; and a circuit for determining the direction of arrival of radio waves from the approximated straight lines.