JP4212933B2 - Radio interference device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radio interference device that transmits a false signal to a radar that performs speed discrimination to reduce its function.
[0002]
[Prior art]
A conventional radio interference device receives radio waves coming from a radar with an antenna, mixes them with a local oscillator signal with a mixer, converts the signals into an intermediate frequency signal, and generates a reception pulse. This pulse is delayed through a delay line that is delayed for a fixed time. In general, this delay time is often set to the pulse width of a radar to be interfered. In order to transmit the delayed intermediate frequency signal, the phase of the local oscillator signal used for reception is adjusted by the phase shifter according to the control signal of the phase amount controller. The phase-adjusted local oscillator signal is modulated by the modulator with the delayed intermediate frequency signal. The modulated signal returned to the original frequency is amplified and transmitted from the antenna.
The above is not a prior art but a generally known technique.
[0003]
[Problems to be solved by the invention]
Since the conventional radio interference device is configured as described above, the delay amount of the received pulse is fixed. Therefore, depending on the distance between the radar and the target equipped with the radio interference device, the transmission wave of the radar may be There are cases where the transmission timing for transmission and the timing at which the interference wave transmitted from the target reaches the radar and is received are the same. At this time, there is a problem that the interference wave cannot be received by the radar. This problem is also known as a problem in which radar reflected waves are not received, and is called Eclipse. In addition, since the delay amount of the jamming device is a fixed delay amount, the average power of the jamming wave transmitted by the jamming device is larger in the case of a signal transmitted with a pulse width of the radar longer than the delay amount. There was a problem of halving.
[0004]
The present invention has been made to solve such a problem. The radar does not overlap the timing at which the radar transmits and the timing at which the interference wave transmitted by the target reaches the radar and is received. An object of the present invention is to obtain a radio interference device that prevents the reception of an interference wave from being received at all and that does not reduce the average power of the interference wave by half regardless of the pulse width transmitted by the radar. It is another object of the present invention to provide another interference effect by changing the reproduction timing for reproducing the interference wave by receiving the transmission pulse of the radar.
[0005]
[Means for Solving the Problems]
The radio interference device according to the present invention includes a receiving unit that receives a radar pulse signal transmitted from a radar, a converting unit that converts a radar pulse signal received by the receiving unit into an intermediate frequency, and a signal that is converted by the converting unit. Storage means for storing the radar pulse signal, and a quantization noise generator for adding the quantization noise to the pulse signal when the pulse signal is stored in the storage means. An inverse quantization converter that inversely quantizes the output signal of the quantization noise generator, an adder that adds the output signal of the inverse quantization converter to the pulse signal of the intermediate frequency, and an output signal of the adder It is configured to include storage means for subtracting and storing the output signal of the quantization noise generator when storing .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. Throughout the drawings, the same reference numerals indicate the same or corresponding parts.
Embodiment 1 FIG.
FIG. 1 is a diagram showing the configuration of a radio interference apparatus according to Embodiment 1 of the present invention. A transmission wave transmitted from a radar is received by an antenna (not shown) and mixed with a signal from a local oscillator 2 by a mixer 1. And converted into a radar transmission pulse signal. This signal is input to a pulse leading edge detector (detecting means) 3, where the leading edge (leading edge) of the pulse signal is detected and a pulse is output to a DRFM (Digital Radio Frequency Memory) (storage means) 4. Remember. The leading edge of the detected pulse is input to the timing control circuit (timing control means) 5. The timing control circuit 5 generates a timing for reproducing a pulse that becomes a source of an interference wave, and controls the DRFM 4. The pulse read from the DRFM 4 is input to the modulator 8. The signal of the local oscillator 2 is given to the modulator 8 via the phase shifter 6 whose phase amount is controlled by the phase amount control circuit 7. The signal modulated by the modulator 8 is transmitted as an interference wave from an antenna not shown.
[0007]
Next, details of the operation will be described. First, the positioning of the radio interference device of the present invention will be briefly described with reference to FIG. The radio interference device of the present invention is mounted on the target 13. A transmission wave 14 (hereinafter referred to as a radar wave) transmitted from the radar 12 (generally installed on the ground) is reflected when it hits the target 13 and is reflected from the target 15 (hereinafter referred to as a radar echo). ) To reach the radar 12. The radar 12 receives this radar echo 15 and knows the distance to the target from the time difference from the transmission timing of the radar wave 14. Also, the speed of the target is known from the difference between the transmission frequency and the reception frequency. When receiving the radar wave 14 from the radar 12, the radio interference device 13 stores the waveform of the detected transmission pulse, and generates and transmits a pseudo radar echo 16 (hereinafter referred to as an interference wave) from the reception timing. is there.
[0008]
Now, returning to FIG. The radar wave 14 received by an antenna (not shown) is mixed with the signal of the local oscillator 2 by the mixer 1 and converted into a pulse signal having an intermediate frequency. This pulse signal is detected by the pulse detector 3 and the leading edge (rising edge) of the pulse is detected and output to the timing control circuit 5. On the other hand, the pulse detector 3 outputs the pulse waveform including the intermediate frequency component to the DRFM 4. FIG. 3 shows the configuration of the DRFM 4, which includes a quantizer 4a such as an A / D (analog / digital) converter, a memory 4b, and an inverse quantizer 4c such as a D / A (digital / analog) converter. Become. The pulse including the intermediate frequency is converted into digital data by the quantizer 4a and stored in the memory 4b.
[0009]
Next, the process until the stored pulse signal is reproduced and the interference wave is transmitted will be described. The digital data of the received pulse stored in the DRFM 4 is controlled by the leading edge signal of the pulse detected by the pulse detector 3. In the pulse reproduction timing control circuit 5, the delay time from the detected pulse leading edge signal is adjusted, the digital data of the pulse is read from the memory 4b, and the pulse signal including the intermediate frequency is reproduced by the inverse quantizer 4c. The regenerated pulse signal is input to the modulator 8. The modulator 8 receives a signal obtained by changing the phase of the signal of the local oscillator 2 used in the mixer 1 by the phase shifter 6 using the control signal of the phase amount controller 7. Modulating by changing the phase is the same as providing the Doppler effect. When the interference wave 16 is received by the radar 12, the pseudo speed of the target 13 (also called deception speed) is detected from the phase difference. .
FIG. 2 is a diagram showing the time relationship between the pulse of the radar 12 and the transmission pulse of the jamming device (the reception pulse on the radar 12 side). The radar wave transmitted by the radar 12 is received by the radar as a radar echo wave on the target 13. Is done. On the radar 12 side, the distance to the target 13 can be calculated based on the reception time difference between the radar wave and the echo wave. However, on the target 13 side, it is difficult to predict the transmission timing of the radar 12 and the reception timing of the radar echo. For this reason, the radio interference device controls the delay time τ based on the leading edge signal of the pulse detected from the received pulse so that the interference wave does not have the same timing as the radar wave. In the figure, the delay time τ from the radar echo is shown. Then, by switching the delay time τ with a relatively long period (for example, about several seconds), a state in which an interference wave is surely efficiently injected into the radar is generated.
[0010]
According to the first embodiment, since the delay time can be changed by changing the pulse reproduction timing, it is possible to optimize the time relationship between the radar echo and the interference wave, and to prevent a decrease in the interference effect due to Eclipse. There is an effect that can be disturbed.
[0011]
Embodiment 2. FIG.
In the first embodiment, the example of the radio interference device configured to switch the delay time with a relatively long cycle is shown. However, in the second embodiment, the configuration is the same as that of the first embodiment and is stored from the DRFM 4. The pulse to be reproduced is controlled by controlling the timing of reading out the pulse data. FIG. 4 is a diagram showing the time relationship of the interference wave transmitted according to the second embodiment. In the reproduction timing control circuit 5, the timing time read from the DRFM 4 is changed stepwise in a short cycle (in the delay time, τ1, τ2, τ3, τ4, τ5) and read to reproduce the pulse.
[0012]
As described above, when the interference pulse is reproduced in a stepwise manner with a timing read out from the DRFM, the power of the interference wave injected into the radar changes, and the same effect as that obtained by adding amplitude modulation to the interference wave. In addition, it is possible to eliminate the need for amplitude modulation components on the radio wave jamming device side, which leads to the effect of downsizing the device.
[0013]
Embodiment 3 FIG.
FIG. 5 is a diagram for explaining generation of an interference wave in the third embodiment. In the first and second embodiments, the reproduction timing control circuit 5 reads out and reproduces the pulse data stored in the DRFM 4 in a relatively long cycle or in a stepwise short cycle in accordance with the pulse leading edge signal, and transmits an interference wave. However, in this embodiment, the delay time is set to almost zero and the interference wave is transmitted. The radar side may also employ processing for removing Eclipse. That is, depending on the distance between the radar and the target, the radar echo wave does not overlap the transmission timing. As shown in FIG. 5, the transmission period (T1, T2, T3...) It is changing slightly. Therefore, if the interference wave is output without delay from the radar reflected wave, the interference wave can be injected into the radar most efficiently.
[0014]
Transmitting an interfering wave without delaying is difficult because the reception and transmission are performed at the same time, and isolation in the radio interfering device cannot be sufficiently obtained. Therefore, in this embodiment, as shown in FIG. 6, each time a radar wave is received, the pulse data is not stored in the DRFM 4, but the pulse data once stored in the DRFM 4 is repeatedly reproduced. However, the reproduction is performed at the timing of the leading edge signal of the pulse detected by the pulse detection circuit every time a radar wave is received.
[0015]
By adopting the configuration as described above, the interference wave can be transmitted without being delayed from the radar reflected wave, so that the interference wave can be injected into the radar most efficiently.
[0016]
Embodiment 4 FIG.
In the first embodiment, the pulse leading edge of the radar wave is detected in the previous stage of the DRFM 4, but the pulse width measuring circuit 3a for measuring the pulse width of the radar wave as shown in FIG. 7 may be used. Good. Other configurations are the same as those in FIG.
The operation will be described with reference to FIG. After being converted to an intermediate frequency pulse signal by the mixer 1, the pulse width of this pulse signal is measured by the pulse width measuring circuit 3a, and the pulse width information is output to the pulse control circuit 5a. Based on the pulse width information, the pulse control circuit 5a causes the DRFM 4 to record for the same pulse width. Then, the pulse is reproduced with a delay of the measured pulse width. The regenerated pulse modulates the phase-shifted signal of the local oscillator 2 by the modulator 8 and transmits it as an interference wave.
FIG. 8 is a diagram showing this state. FIG. 8A shows the time relationship when the pulse width of the radar wave received by the radio interference device is wide, and FIG. 8B shows the time relationship when the pulse width is narrow. Yes. Even if the pulse width (PW) is wide or narrow, it is delayed by a delay time (τ) having the same width as the pulse width (PW).
[0017]
By adopting such a configuration, even if the radar wave of the radar has a wide pulse width or a narrow pulse width, it is possible to efficiently interfere without reducing the average power that the interference wave injects into the radar.
[0018]
Embodiment 5 FIG.
In the embodiment described above, the configuration in which the detection circuit for detecting the leading edge of the pulse or the pulse width measurement circuit is provided in the previous stage of the DRFM 4 has been described. An embodiment of the disturbing device will be described.
FIG. 9 is a diagram showing the configuration of the fifth embodiment, in which an adder 4d is provided between the quantization noise generator 9, the quantizer 4a in the DRFM 4, and the memory 4b. Other configurations are the same as those of the first embodiment.
In FIG. 9, a quantization noise is generated by a quantization noise generator 9, and this quantization noise is superimposed on a signal obtained by converting a received radar pulse signal of an intermediate frequency into digital data by a quantizer 4a by an adder 4d. To do. The superimposed digital data is stored in the memory 4b. The stored digital data is read out, converted into an intermediate frequency pulse signal by the inverse quantizer 4c, modulated by the modulator 8, and transmitted as an interference wave.
[0019]
With this configuration, if the quantization noise to be superimposed is appropriately selected, an effective interference wave in which the noise is superimposed can be transmitted without adding components to the radio interference wave.
[0020]
Embodiment 6 FIG.
In the fifth embodiment, the quantization noise is superimposed and stored in the DRFM 4. However, as shown in FIG. 10, a subtractor 4e is used instead of the adder 4d of the DRFM 4, and the quantization noise generator 9 is used. Is input to the subtracter 4e and input to the inverse quantization converter 10, and then the noise converted into an analog signal is converted into a radar pulse signal that has been converted to an intermediate frequency signal by the mixer 1 before the DRFM 4. The adder 11 may add the values. The signal stored in the DRFM 4 is a signal with less noise, read out from the DRFM 4, converted into a pulse signal having an intermediate frequency by the inverse quantizer 4 c, and input to the modulator 8.
[0021]
By adopting such a configuration, by performing a series of processes for adjusting quantization noise, noise included in the output waveform of the interference wave can be reduced compared to when radar pulse data is simply stored / reproduced by DRFM. It can be reduced and effective radio interference can be achieved.
[0022]
【The invention's effect】
As described above, according to the present invention, the receiving means for receiving the radar pulse signal transmitted from the radar, the converting means for converting the radar pulse signal received by the receiving means to an intermediate frequency, and the converting means Storage means for storing the converted radar pulse signal, and a quantization noise generator for adding quantization noise to the pulse signal when storing the pulse signal in the storage means, , An inverse quantization converter that inversely quantizes the output signal of the quantization noise generator, an adder that adds the output signal of the inverse quantization converter to the pulse signal of the intermediate frequency, and an output of the adder since a configuration that includes a storage means for and storing subtracts the output signal of the quantizing noise generator in storing signals, by performing a series of processes for adjusting the quantization noise, simply radar Rusudeta than when stored / playback DRFM and can reduce the noise included in the output waveform of the interference wave, an effect that it is effective jamming.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a first embodiment of the present invention.
FIG. 2 is a diagram showing a relationship between an interference wave and a radar wave according to the present invention.
FIG. 3 is a diagram showing a configuration of a DRFM of the present invention.
FIG. 4 is a diagram showing a relationship between an interference wave and a radar wave according to Embodiment 2 of the present invention.
FIG. 5 is a diagram showing a relationship between an interference wave and a radar wave according to Embodiment 3 of the present invention.
FIG. 6 is a diagram showing interference wave reproduction timing in Embodiment 3 of the present invention.
FIG. 7 is a diagram showing a configuration of a radio interference device according to Embodiment 4 of the present invention.
FIG. 8 is a diagram for explaining average power of jamming waves in Embodiment 4 of the present invention.
FIG. 9 is a diagram showing a configuration of a radio interference device according to Embodiment 5 of the present invention.
FIG. 10 is a diagram showing a configuration of a radio interference device according to Embodiment 6 of the present invention.
FIG. 11 is a diagram showing a positional relationship between the radio interference device of the present invention and a radar.
[Explanation of symbols]
1 mixer, 2 local oscillator, 3 pulse detector, 4 DRFM, 4a quantizer, 4b memory, 4c inverse quantizer, 4d adder, 4e subtractor, 5 timing control circuit, 6 phase shifter, 7 phase quantity Control circuit, 8 modulator, 9 quantization noise generator, 10 inverse quantization converter, 11 adder, 12 radar, 13 target, 14 radar wave, 15 radar echo wave, 16 interference wave.

Claims (1)

Receiving means for receiving a radar pulse signal transmitted from the radar;
Conversion means for converting the radar pulse signal received by the receiving means into an intermediate frequency;
Storage means for storing the radar pulse signal converted by the conversion means;
A quantization noise generator for adding quantization noise to the pulse signal when storing the pulse signal in the storage means;
The quantization noise is superimposed by an inverse quantization converter that inversely quantizes the output signal of the quantization noise generator, and an adder that adds the output signal of the inverse quantization converter to the pulse signal of the intermediate frequency. And a storage means for subtracting and storing the output signal of the quantization noise generator when storing the output signal of the adder.

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