JPH0427509B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a direction finder display device that detects an azimuth signal having a phase corresponding to the azimuth of an incoming radio wave and displays the azimuth of an incoming radio wave.

<Prior art> Conventionally, in this type of direction finder, the direction is indicated by the automatic direction of the pointer using an analog meter, or in the case of a dot type display, for example, one light emitting display element is used. Display is performed by lighting up one light emitting element arranged in a circle at equal intervals and at an angle corresponding to the indicated direction, and this is also a type of analog display. These conventional analog displays can be read intuitively to read the approximate direction of arrival, but in order to read the correct azimuth angle, it is necessary to read the direction indicated by the pointer or the light emitting element that is lit. The direction must be read from an angular scale and cannot be read instantaneously.

<Summary of the invention> The purpose of this invention is to quantify the detected azimuth angle, further correct the obtained azimuth value as necessary, and
To provide a display device for a direction finder that can accurately determine and immediately display the average value of azimuth values, and can also display the azimuth correctly.

According to this invention, an azimuth signal having a phase corresponding to the azimuth of an incoming radio wave is detected from a received signal of an incoming radio wave, the phase of the azimuth signal is converted into a numerical value, and the numerical value is further corrected as necessary. A plurality of numerical values indicating the direction of the incoming radio waves or their modified values are averaged, and the obtained accurate average value is displayed on a digital display. Since the direction of the incoming radio wave is displayed as a number in this way, the viewer can accurately detect the direction the moment they see it.

<Embodiments> Hereinafter, embodiments of a direction finder indicator according to the present invention will be described with reference to the drawings. In FIG. 1, an azimuth signal having a phase corresponding to the direction of the arriving radio wave is detected from the received signal by the azimuth signal detection section 11.
In the figure, four rod-shaped antennas 1N, 1S, 1
E and 1W are placed at each corner in the positive direction, and the antenna 1N is on the north side of the center, and the antenna 1S is on the north side.
is on the south side, 1E on the east side, and 1W on the west side.
These antennas are switched and connected to a receiver 13 by a switching signal from a control signal generator 12. For example, the antennas 1N and 1S are alternately received twice, and as shown in FIG. 2A, the received signal 2N from the antenna 1N and the received signal 2S from the antenna 1S are received alternately twice. Next, antenna 1E
The received signal 2E from the antenna 1W and the received signal 2W from the antenna 1W are received alternately twice, and then the antenna 1N is received again, and the same process is repeated.

Received signals from these antennas are amplified by a circuit 14 in a receiver 13, further converted into intermediate frequency signals, and then sequentially received by a phase detector 15 to detect a phase change between each antenna signal. Antenna 1N as shown in Figure 2B
A signal 3N corresponding to the phase difference between the signal 2N from the antenna 1S and the signal 2S from the antenna 1S is detected, and when changing from the signal 2S to the signal 2N, the phase difference is reversed, so the signal 3S switches in a pulse-like manner. Obtained in points. Similarly, the signals corresponding to the phase difference between the antennas 2E and 2W are sequentially transmitted to the signals 3E and 3, respectively.
Obtained as W. The phase difference between the received signals 2N and 2S from the antennas 1N and 1S becomes larger as the arrival direction of the radio waves approaches the arrangement direction of the antennas 1N and 1S. The phase difference becomes zero, and a phase difference corresponding to the direction of arrival is obtained. The antenna switching frequency component is extracted by the wave detector 16 from the output of the wave detector 15 in which such a phase difference is detected. wave device 16
The outputs are switched by the antenna switching circuit 17 to the respective integration circuits, that is, time constant circuits 4N, 4S, 4E, and 4W each consisting of a capacitor and a resistor, and the corresponding ones are accumulated.

The signals integrated by the integrating circuits 4N, 4S, 4E, and 4W are switched by an analog switching circuit 18, and the integrating circuits
N, 4E, 4S, and 4W are repeatedly extracted in the order, and a signal train as shown in FIG. 2C, for example, is obtained. That is, in FIG. 2C, the integrating circuits 4N, 4S,
Each DC output of 4E, 4W is 5N, 5S, 5E, 5
W, the output of the switch circuit 18 is 5N, 5
E, 5S, 5W are repeated in this order. This switching speed can be arbitrarily selected, for example, one quarter of the switching speed of the switching circuit 17. This switching circuit 18
The repetition frequency component of the output is extracted by the wave generator 19 and converted into a sine wave signal as shown in FIG. 2D, and further converted into a square wave signal as shown in FIG. 2E by the waveform shaping circuit 21. The phase of this square wave signal corresponds to the direction of arrival of the radio wave with respect to the switching signal of the switching circuit 18. The principle of this azimuth signal detection section 11 is explained in, for example, Japanese Patent Application No. 127200/1983 (Japanese Patent Application Laid-open No. 027073/1983).

For example, for the output square wave signal of the waveform shaping circuit 21 shown in FIG. 2E, the switching reference signal is as shown in FIG. 2F, and the phase difference between these two signals is detected as a numerical value (digital value). to obtain numerical data corresponding to the direction of the incoming radio wave. Control signal generator 12
uses a stable clock from the reference clock oscillator 22 to switch the antennas 1N, 1S, 1E, and 1W, control the switching circuits 17 and 18, and also generate the reference signal shown in FIG. 2F. For example, when the reference signal rises, the flip-flop 23
is set, the Q output opens the gate 20, and the clocks passing through the gate 20 are counted by the counter 24. The flip-flop 23 is reset by the rise of the output of the waveform shaping circuit 21. Therefore, the counter 24 counts the clock pulses (G in FIG. 2) from the rise of the reference signal to the rise of the square wave signal having a phase corresponding to the arrival direction of the radio wave. This count value is calculated by the central processing unit,
It is taken into so-called CPU25, and then CPU2
5 resets the counter 24.

The CPU 25 performs display operations by sequentially reading and decoding the programs stored in the ROM 26, and when the azimuth data obtained by the counter 24 is fetched a predetermined number of times, the azimuth data is averaged and the azimuth data is averaged. The average value is expressed as an angle on the numerical display 27.
to be displayed. A RAM 28 is provided for storing data required for this purpose, and an interval time 29 is provided for controlling panel keys and the like. Furthermore, this display operation is started by detecting the arrival of a radio wave, and the output of the circuit 14 of the receiver 13 is also branched into the radio wave arrival detector 31, and the detection output of the radio wave arrival detector 31 is given to the CPU 25. When the angle is displayed, the CPU 25 starts the operation for displaying the angle. Furthermore, in this example, an analog display 32 is provided in which light emitting diodes are arranged on a circle at regular intervals and the light emitting diodes at angular positions corresponding to the angle of the incoming radio waves are lit to display the display. .

The CPU 25 performs operations as shown in FIG. 3, for example.

That is, in step _S1 , it is always detected whether the radio wave arrival detection signal Sig is turned on or not.
If it is off, the flag F is turned off in step _S2 and the process returns to step _S1 . This flag F is stored in the flag storage area 28 in the RAM 28, for example, as shown in FIG.
It is stored in a. When the arrival direction of the radio wave is detected in step _S1 , the process moves to step _S3 , and then
In _S3 , it is checked whether the data can be taken in, that is, whether the counting operation of the counter 24 has been completed.If the counting operation has not been completed, the process returns to step _S1 , and when the counting operation has been completed, it is checked. At step _S4 , data representing the count value of the counter 24 is taken in. After that, in step _S5 , it is checked whether flag F is off, and if flag F is off, it means that no radio waves have arrived until then, and in that case, in step _S6 , flag F is turned on and Let the data be average data. This average data is stored in average data area 28b within RAM28.

If the flag F is on in step _{S5 , the process moves to step S7 ,} where the count value n of the average number counter is incremented by 1, and the average number n is stored in the counter area 28c. At the same time, the operation moves to the data averaging routine _R1 . As shown in FIG. 5, the data averaging routine _R1 checks whether the added value D _s = _o 〓 D is zero in step S ₈ , and if the added value D _s is zero in step S ₈ , the process goes to step S ₉ . Immediately move on, and in step _S8 , if the added value is not zero,
If there is already an added value, it is detected in step _S10 whether the value obtained by subtracting the captured data D from the average data is greater than a predetermined value, for example 512. In this embodiment, this value 512 corresponds to the case where 360 degrees corresponds to 1024 degrees, and is half of that value, and corresponds to 180 degrees. If the average value calculated up to that point is 180° or more larger than the imported data D, step
Proceed to step S ₁₁ , add 1024 to the imported data D, and use the result as imported data D. Step S ₉
Move to. If the difference is smaller than 512 in step _S10 , it is checked in step _S12 whether the value obtained by subtracting the captured data D from the average data is smaller than -512, that is, if the captured data D is smaller than the average data up to that point. Check whether it is larger than 180°, and if it is larger than 180°, move to step _S13 , subtract 1024, which is 360°, from the captured data D, and take the result as captured data D.
Proceeding to _S9 , if the difference between the data acquired in step _S12 and the average data is less than 180°, the process immediately proceeds to step _S9 .

In the operations in these steps _S10 to _S13 , when the measured data (azimuth) is around 0°, a data value slightly larger than 0° and a large data value slightly before 0° are measured; If averaged as is, the obtained measurement data would be around 180°, which is a completely different value from 0°. Therefore, processing is performed to prevent such errors from occurring.

In step _S9 , the acquired data D obtained as a result of step _S8 , _S11 , or _S13 is added to the total value _Ds up to that point to obtain additional data.
D _s =ΣD is obtained and stored in the addition data area 28d of the RAM 28. After that, in step _S14 , it is checked whether the added data _Ds is smaller than 0, and if it is positive, the process moves to step _S15 .
If it is negative, the addition data D _s is added in step _S16 .
1024×n, that is, the value of n times 360° is added and used as addition data D _s . This is added to the addition data area 28.
Store in d. Thereafter, the process moves to step _S15 , and this added data _Ds is divided by the n value at that time to obtain average data, which is stored in the average data storage section 28b.

When the average data routine _R1 is completed in this way, it is checked in step _S16 in FIG. 3 whether the average number n matches a predetermined value N, and if not, the process returns to step _S1 . Generally, radio waves arrive continuously, and in this state, steps S ₁ , S ₃ , S ₄ , and
The processes of step S ₅ , step S ₇ , and step S ₁₆ are repeated. When n reaches the predetermined average number of times N in step _S16 , the average number value n and data total value _Ds are set to 0 in step _S17 , and an angle calculation, that is, an operation of 360÷1024×, is performed to obtain the average data. Obtain the numerical value DEG indicating the corresponding angle.
This value is checked in step _S18 to see if it is larger than 360°, and if it is smaller, the step
Proceed to S ₁₉ , and if it is larger, enter that value in step S ₂₀ .
360° is subtracted from DEG and the result is used as DEG, and the process moves to step _S19 , where the numerical value of this azimuth angle is displayed on the display 27.

When displaying on the analog display 32, add 2.5° to the numerical data DEG calculated as above, that is, the display interval between the light emitting elements of the display 32.
Add half the value of 5°, divide the added value by 45°, detect in which 45° area of the 45° division drive, and then calculate the value of the division result. The value is divided by 5 and the light emitting element corresponding to the value is lit to display the value.

<Effects> As described above, according to the direction finder display according to the present invention, since the direction of the arriving radio wave is displayed as a numerical value, the direction of arrival can be immediately read as an accurate value by looking at this. Since the direction is detected as a numerical value in this way, it can be transmitted accurately without any errors.

If the reception condition is unstable, the detected direction of arrival may fluctuate by, for example, ±45 degrees, but even in such cases, the present invention can perform rational averaging processing as shown in Figure 5. Therefore, the arrival direction of radio waves can be detected correctly.

Furthermore, although averaging processing is performed in this way, steps from step _S6 to
The process moves to _S17 , where the first received data is directly designated as an azimuth signal, and is therefore immediately detected and displayed without any delay in detection by averaging processing. Therefore, it is possible to reliably detect the direction of radio waves that arrive instantaneously.

In the above, the operation shown in Fig. 1 was performed to obtain the direction signal, but the operation is not limited to this type of operation. In other words, the present invention can be applied to direction finders that can obtain a signal with a phase corresponding to the direction of arrival, such as those of the goniometer type.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a direction finder display according to the present invention, FIG. 2 is a waveform diagram for explaining its operation, FIG. 3 is a flowchart showing an example of its processing operation, and FIG. The figure shows a storage area in the RAM, and FIG. 5 is a flowchart showing an example of processing of the averaging routine. 1N, 1S, 1E, 1W: Antenna, 4N, 4
S, 4E, 4W: Integrating circuit, 11: Direction signal detection section, 13: Receiver, 15: Phase detection circuit, 17,
18: switching circuit, 21: waveform shaping circuit, 22: clock oscillator, 12: control signal generator, 25:
CPU, 24: Counter, 27: Digital display.

Claims (1)

[Scope of Claims] 1. An azimuth signal detection means for obtaining an azimuth signal having a phase corresponding to the azimuth of an incoming radio wave; an azimuth value conversion means for obtaining a numerical value corresponding to the azimuth of an incoming radio wave from the phase of the azimuth signal; A display device for a direction finder, comprising averaging means for averaging a plurality of azimuth values, and display means for digitally displaying the averaged azimuth values, wherein the averaging means averages the azimuth values until then. Compare with the average value of the azimuth values to determine whether the former is the first case smaller than the latter by 180 degrees or more, the third case larger than the latter by 180 degrees, or the second case neither smaller nor larger than the latter by 180 degrees. In the case of the first case above, the direction value is compared with 360
a first azimuth value correction means for obtaining a first correction value of the azimuth value by adding the numerical values of degrees;
a second azimuth numerical value correction means for obtaining a second correction value of the azimuth value by subtracting the numerical values for 360 degrees; Adding means for adding the numerical values as they are and the above-mentioned second modified value respectively to the cumulative value of the azimuth numerical values up to that point, and cumulative value positive/negative for determining whether the output cumulative value of the adding means is negative or not. judgment means; cumulative value correction means for adding a value obtained by multiplying the number of data samples by the numerical value for 360 degrees to obtain a corrected value for the cumulative value when the output cumulative value is negative; and a dividing means for calculating the average value of the azimuth values by dividing the output cumulative value or its modified value by the number of data samples depending on whether the calculated value is positive or negative. Detector indicator.