JPH09113604A - Radio wave classifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more accurately classify pulse signals from a plurality of radio wave radiating sources. SOLUTION: A radio wave classifying device classifies radio waves from a plurality of radio wave radiating sources in accordance with the rate of change of the intensity of a received electric field and outputs the classified radio waves for display. When the classifying device classifies the radio waves, gate width setting circuits 50-1 to 50-N specify a prescribed range with the intensity of the electric field received at the preceding time as the central figure. Pulse amplitude gate circuits 40-1 to 40-N output the received radio waves as the same kind of radio waves as those of the preceding time when the intensity of the received electric field falls within the range or another kind of radio waves when the received electric field intensity does not fall within the range. Since the radio waves are classified in accordance with the received electric field intensity in addition to the frequency, arriving azimuth, and pulse-repetition frequency of the radio waves, pulse signals can be classified more accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave classifying device, and more particularly to a radio wave classifying device for receiving pulsed radio wave signals emitted by a plurality of radars whose pulse repetition frequencies change intricately and classifying respective radio wave emission sources. .

[0002]

2. Description of the Related Art Generally, a radio wave detecting device receives a pulse signal radiated by a radar such as an aircraft or a ship, and measures the frequency, the pulse width, the direction of arrival, the pulse repetition frequency, etc. which characterize the pulse signal, It is also possible to identify and orient the radiation source by collecting and analyzing pulse signals in the past and comparing with the summarized data.

In order to detect radio waves radiated by an aircraft or a ship, it is necessary to classify received pulse radio signals (hereinafter referred to as pulse signals) and display the pulse radio signals according to the classification result. is there. Conventionally, a radio wave classification device for performing this pulse signal classification is disclosed in, for example, Japanese Patent Laid-Open No. 5-2037.
As described in Japanese Patent Publication No. 14, the information on the frequency of the radio wave, the arrival direction of the radio wave, and the repetition frequency of the pulse is used to classify the received pulse signal group by the radiation source.

FIG. 11 is a block diagram showing an example of a conventional radio wave classifying apparatus. In the figure, a conventional radio wave classification device includes a reception / measurement circuit 202 that receives a pulse signal from a radiation source that transmits a pulse signal, and measures the arrival direction, frequency, and arrival time of the emitted radio wave, and the measured frequency and arrival time. A frequency / arrival direction classification circuit 203 that classifies pulse signals based on the azimuth, and a pulse repetition frequency is measured from the arrival time of the classified pulse signals. When the pulse repetition frequency has periodicity, the same radiation source is used. It is configured to include a pulse repetition frequency classification circuit 205 for further classification as a pulse signal and a display circuit 207 for displaying the classified pulse signal 254. In addition, 201 is an antenna.

In such a configuration, when a pulse signal from a radio wave radiation source such as an aircraft or a ship is input through the antenna 201, it is received by the reception / measurement circuit 202, and the arrival direction, frequency and arrival time of the emitted radio wave are received. To be measured. The frequency / arrival direction classification circuit 203 classifies the pulse signals based on the measured frequency and arrival direction. Further, the pulse repetition frequency classification circuit 205 measures the pulse repetition frequency from the arrival time of this classified pulse signal. Then, the pulse repetition frequency classification circuit 205 further classifies as a pulse signal from the same radiation source when the pulse repetition frequency has periodicity. In this way, the classified pulse signals are displayed on the display circuit 20.
7 is displayed.

[0006]

In the conventional radio wave classifying apparatus described above, signals are classified only by frequency, direction of arrival and pulse repetition frequency. Then, when the frequency and the arrival direction are the same, they are classified by the pulse repetition frequency. However, if the pulse repetition frequency is complicated and changes randomly, the signal sources may not be correctly classified and may be output and displayed in a state of interference.

Therefore, there has been a demand for the realization of a radio wave classifying device which can more correctly classify signal sources.

The present invention has been made to solve the above-mentioned drawbacks of the prior art, and an object thereof is to provide a radio wave classifying device capable of performing more accurate signal source classification.

[0009]

A radio wave classification device according to the present invention classifies radio waves radiated from a plurality of radio wave radiation sources into N (N is an integer of 2 or more) according to the rate of change of the received electric field strength. It is characterized in that it has a classification means for sending as N kinds of classification outputs.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The operation of the present invention is as follows.

Radio waves radiated from a plurality of radio wave radiation sources are classified according to the continuity of changes in the amplitude value of the received pulse signal with respect to time, that is, the rate of change in the received electric field strength, and the results are output and displayed. .

More specifically, when the received electric field strength is a value within a predetermined range centered on the received electric field strength at the time of the previous radio wave radiation, the received electric wave is sent as one type and a value outside the predetermined range is output. When it is, the received radio wave is transmitted as another type.

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a radio wave classification device according to the present invention. In the figure, a radio wave classifying apparatus according to an embodiment of the present invention shows a receiving circuit 20 for receiving a pulse signal through an antenna 10 and converting it into a video signal.
And a pulse amplitude measuring circuit 30 for measuring and outputting the pulse amplitude of the video signal output from the receiving circuit 20,
A gate width setting circuit 50-i (i = 1 to N, the same applies hereinafter) that determines the passage amplitude range of the pulse signal, and a pulse amplitude gate circuit that outputs and classifies the pulse signal according to the determined passage amplitude range. 40-i.

As shown in FIG. 2, the pulse amplitude measuring circuit 30 includes a video signal amplitude PA (Pulse A).
It is configured to include a peak hold (PH) circuit 32 which holds and outputs the peak value of the (mplitude). The signal 32 having the held peak value, that is, the voltage value corresponding to the pulse amplitude is input to the pulse amplitude gate circuit 40-1.

As shown in FIG. 3, the pulse amplitude gate circuit 40-i includes a comparator 41 which receives an upper limit signal 541 indicating the upper limit of the passage amplitude range of the pulse signal as a reference input,
Lower limit signal 542 indicating the lower limit of the passing amplitude range of the pulse signal
Is used as a reference input, an AND circuit 43 that obtains the logical product of the comparison outputs of the two comparators 41 and 42, and an inverting circuit 44 that inverts the logical product output of the AND circuit 43.
And switches 45 and 46 in which only one of them is turned on according to the outputs of the AND circuit 43 and the inverting circuit 44.
It is comprised including. Then, when the switch 45 is in the ON state, the signal 32 is output as the signal 47 at the output terminal 1-i.
And the signal 32 is output as the signal 46 to the output terminal 2-i when the switch 46 is in the ON state.

The gate width setting circuit 50-i adds the signal from the signal generator 51 to the output signal to the output terminal 1-i of the pulse amplitude gate circuit 40-i, as shown in FIG. It is configured to include an adder 52 which sends out as an upper limit signal 541 and a subtracter 53 which subtracts the signal from the signal generator 51 from the output signal and sends out as a lower limit signal 542. Since the signal generator 51 always sends out a constant signal, the upper limit signal 541 and the lower limit signal 542 centered on the voltage value (received electric field strength) of the output signal to the output terminal 1-i of the pulse amplitude gate circuit 40-i. In the pulse amplitude gate circuit 40-i, it is determined whether or not the voltage value of the pulse signal to be input next time is within the passing amplitude range defined by.

As a result of the judgment in the pulse amplitude gate circuit 40-i, if it is within the passing amplitude range, it is sent from the output terminal 1-i as a pulse signal from the same radiation source. On the other hand, if it is not within the passing amplitude range, it is sent from the output terminal 2-i as a pulse signal from a radiation source different from the previous radiation source, and the pulse amplitude gate circuit 40- (i + 1) outputs the same signal. A decision is made.

Therefore, when the received electric field strength of the received radio wave is a value within a predetermined range centered on the received electric field strength at the time of the previous radio wave radiation, the received electric wave is regarded as one of the N kinds of classification outputs. Is transmitted, and when the value is out of the predetermined range, the received radio wave is transmitted as another type of N types of classification output.

The signals output from the signal generator 51 to the adder 52 and the subtractor 53 may have the same voltage value or different voltage values.

Here, when the pulse wave radiated from the directional antenna of the radar is received and the state of change of the pulse amplitude value with respect to time is examined, an envelope curve as shown in FIG. 5 is drawn. That is, since a radio wave beam from a radio wave radiation source rotates, the pulse amplitude value gradually increases with time, as shown by a curve P1 in the figure, and the pulse amplitude value gradually decreases with a certain value as a peak. It will become. Similarly, in the case of the curve P2 by another radio wave radiation source, the pulse amplitude value gradually increases with time, and gradually decreases with a certain value as a peak.

Curves P1 and P as shown in FIG.
In the case of 2, both curves intersect at the intersection Q. For this reason,
Since the same pulse amplitude value is input from two radiation sources at this intersection, both radiation sources cannot be distinguished. However, since the continuity of the change in the amplitude value over time is different for each radiation source, the curvature of both curves, that is, the rate of change of the received electric field strength is different. Therefore, after the elapse of the predetermined time, the pulse amplitude value of the pulse signal from one of the radiation sources becomes a value outside the above-mentioned passing amplitude range, and hence it is possible to perform accurate classification thereafter. That is, in the present invention, the radio waves are classified according to the rate of change of the received electric field strength.

Returning to FIG. 1, in such a configuration, the pulse signal output from the antenna 10 is received by the receiving circuit 20, converted into a video signal and output. The pulse amplitude measuring circuit 30 measures and outputs the pulse amplitude of the input video signal. When the first pulse signal is input to the pulse amplitude gate circuit 40-1, it is output to the output terminal 1-1 as it is. In addition, the gate width setting circuit 50-
1 determines the passing amplitude range of the pulse signal to be input next based on the amplitude value of the input pulse, and outputs this.

Next, the second pulse signal is input to the pulse amplitude gate circuit 40-1, and if the pulse amplitude value is within the pass amplitude range determined by the gate width setting circuit 50-1, For example, it is determined that the pulse signal is from the same radiation source as the first pulse signal and is output to the output terminal 1-1. Here, the gate width setting circuit 50-1 further determines the passing amplitude range of the pulse signal input next,
Output this. Therefore, the passing amplitude range of the pulse signal is updated.

On the other hand, if the pulse amplitude value of the pulse signal input to the pulse amplitude gate circuit 40-1 is out of the passing amplitude range, the pulse signal has the pulse amplitude value.
-2, and is output to the output terminal 1-2 as it is. Here, the gate width setting circuit 50-2 to which the pulse width amplitude value is input determines the passing amplitude range of the pulse signal to be input next, and outputs this. Therefore, the passing amplitude range of the pulse signal is updated.

Hereinafter, the pulse amplitude gate circuit 40-3 and the gate width setting circuit 50-3 to the pulse amplitude gate circuit 4 will be described.
The same processing is performed up to 0-N and the gate width setting circuit 50-N. Therefore, by using this device, it is possible to more accurately classify the pulse signal groups from N radiation sources by radiation source.

In the case where a plurality of radiation sources exist in the same azimuth, when classified by the conventional apparatus, the classification based on the pulse amplitude is not performed, so that the plurality of radiation sources are displayed as one radiation source. There was a case. That is, for example, as shown in FIG. 6A, when two radiation sources (Δ) are present in the vicinity of 90 ° azimuth, when classified by the conventional device, It is displayed as one radiation source as shown. The same applies to the two radiation sources (Δ) near the azimuth of 300 °.

On the other hand, according to the present apparatus, since the classification is performed based on the pulse amplitude, it is not displayed as shown in FIG. 7B, but as shown in FIG. Is displayed correctly.

FIG. 7 is a block diagram showing a device configuration example in the case where the radio wave classification according to the present invention is used in combination with the radio wave classification based on the frequency, azimuth and pulse repetition frequency which has been conventionally used, and is equivalent to FIG. Are denoted by the same reference numerals. In the figure, this radio wave classifying device has a configuration in which a storage memory 204 and a pulse amplitude classifying circuit 206 are added to the device of FIG.

The storage memory 204 is provided between the frequency / arrival direction classification circuit 203 and the pulse repetition frequency classification circuit 205 and is a memory for storing the classified pulse signals. During the storage, the frequency and the direction of arrival are used as the address. That is, as shown in FIG. 8, the pulse signal that is output from the output frequency arrival direction classification circuit 203 after being classified based on the frequency and the arrival direction is output at the frequency and the direction (0 ° to 360 °). It divides and accumulates. That is, it is considered that the pulse data that enter the same grid (same address) in FIG. 8 are due to pulse signals from the same radiation source.

Further, the pulse repetition frequency classification circuit 205
Is a pulse repetition period PRI (Puls) based on the data in the storage memory 204, as shown in FIG.
The PRI measuring unit 251 for measuring eRepetition Interval, and when the measured pulse repetition period PRI is not constant or a specific frequency such as stagger, outputs an enable signal 253 for enabling the pulse amplitude classification circuit 206. , And an output unit 25 for transmitting the classified signal 254 when the predetermined value is not exceeded.
2 is included.

Returning to FIG. 7, the pulse amplitude classification circuit 206
Is for classifying pulse signals with the same configuration as the pulse amplitude gate circuit 40-i and the gate width setting circuit 50-i in FIG. In this example, the pulse amplitude classification circuit 206 classifies the pulse signal based on the pulse amplitude data in the storage memory 204 only when the pulse repetition frequency classification circuit 205 cannot classify the pulse signal. In the pulse amplitude classification circuit 206, the storage memory 204
The pulse amplitude data is sequentially read out from and is subjected to digital / analog conversion.

In this structure, the receiving / measuring circuit 20
2 receives the pulse signal from the radiation source via the antenna 201, measures the frequency, the direction of arrival, and the pulse amplitude value, converts it into a quantized signal, and outputs this quantized signal for each pulse. The frequency arrival direction classification circuit 203 classifies the input pulse signal based on the frequency and the arrival direction and outputs it. The storage memory 204 stores the classified pulse signals by using the frequency and the arrival direction as addresses.

The pulse repetition frequency classification circuit 205 reads the pulse signal data from the storage memory 204, further classifies the pulse signal data having a regular pulse repetition frequency as pulse signals from the same radiation source, and displays the data. Output to 207. This regularity refers to the case where the pulse repetition frequency is constant or staggered (the pulse repetition frequency differs for each pulse).

If the pulse repetition frequency has no regularity, the pulse amplitude classification circuit 206 reads the data from the storage memory 204, further classifies the pulse signal by the same method as described above, and outputs it to the display circuit 207.

The display circuit 207 displays information on the classified radiation source of the pulse signal. In the display circuit 207, if there is data in the past which seems to be data from the same radiation source, the same name as that of the past data is given and the data is displayed. If there is no suspected data from the same source, give it a new name and display it. This display process will be described with reference to FIG. In FIG. 10, first, the past data is read and the read data is compared with the classified pulse signal (step 101). If the data is from the same radiation source, it is displayed with the same name as that given when the past data was displayed (step 102 → 10).
3).

If the data is not from the same radiation source, it is judged whether all the data are compared (step 10).
4). If there is data that has not been compared yet, the next data is read and compared in the same manner (step 104 → 101).
→ 102 ...).

As a result of comparison with all the data, if there is no data from the same radiation source, the data is displayed with a new name (step 104 → 105).

In this way, if data from the same radiation source has been displayed in the past, it is displayed with the same name.

As described above, in addition to the conventional pulse signal based on the frequency, arrival direction and pulse repetition frequency, classification is also performed based on the amplitude data of the pulse signal.
It is possible to more accurately classify pulse signals from a plurality of radiation sources that have no periodicity in the pulse repetition frequency within the same frequency and direction of arrival. In short, this radio wave classification device performs classification according to the rate of change of the received electric field strength in addition to the frequency, direction of arrival, and pulse repetition frequency.
More accurate signal classification can be performed.

[0041]

As described above, according to the present invention,
By performing classification according to the rate of change of the received electric field strength in addition to the arrival direction and the pulse repetition frequency, there is an effect that more accurate signal classification can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a radio wave classification device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration example of an amplitude measurement circuit.

FIG. 3 is a block diagram showing an internal configuration example of a pulse amplitude gate circuit.

FIG. 4 is a block diagram showing an internal configuration example of a gate width setting circuit.

FIG. 5 is a characteristic diagram showing a change in pulse amplitude value.

FIG. 6 is a diagram showing display contents by a display circuit,
(A) is the case according to the present invention, and (b) is the case according to the prior art.

FIG. 7 is a block diagram showing a configuration example of a radio wave classification device when used in combination with the present invention and radio wave classification based on a frequency, an azimuth, and a pulse repetition frequency that are conventionally used.

FIG. 8 is a diagram showing a method of storing data in a storage memory.

FIG. 9 is a block diagram showing an internal configuration example of a pulse repetition frequency classification circuit.

FIG. 10 is a flowchart showing display processing in the display circuit.

FIG. 11 is a block diagram showing a configuration of a conventional radio wave classification device.

[Explanation of symbols]

 1-1 to 1-N, 2-1 to 2-N output terminal 20 receiving circuit 30 pulse amplitude measuring circuit 40-1 to 40-N pulse amplitude gate circuit 50-1 to 50-N gate width setting circuit 202 receiving / Measurement circuit 203 Frequency / arrival direction classification circuit 204 Storage memory 205 Pulse repetition frequency classification circuit 206 Pulse amplitude classification circuit 207 Display circuit

Claims (3)

[Claims] 1. A classifying unit that classifies radio waves radiated from a plurality of radio wave radiation sources into N (N is an integer of 2 or more) in accordance with a rate of change of the received electric field intensity and sends out as N types of classification outputs. A radio wave classification device characterized in that 2. The classifying means includes a receiving means for receiving the radio wave, and N level comparing means for sending out as the classification output when a change in the received electric field strength level of the received radio wave received is within a predetermined range. The radio wave classification device according to claim 1, further comprising: 3. The radio wave is radiated from the plurality of radio wave radiation sources at predetermined intervals, and the level comparing means sets the received electric field strength of the received radio wave to a predetermined value centering on the received electric field strength at the time of the previous radio wave radiation. When the value is within the range, the received radio wave is transmitted as one type of the N types of classification output, and when the value is outside the predetermined range, the reception radio wave is received as the other type of the N types of classification output. The radio wave classifying device according to claim 2, wherein radio wave is transmitted.