JPH01224687A - Proximity fuse - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a proximity fuse installed on a guided flying object, and particularly to a proximity fuse that prevents malfunctions due to external interference waves and optimizes the timing of operation. It is.

[Conventional technology]

FIG. 4 is a diagram showing the configuration of a conventional proximity fuse.

(1) is an antenna that emits a signal into the air and receives the signal reflected by the target aircraft, (21 is a power divider that equally distributes power, and (3) is a transmitter that generates a continuous signal. , (4) is a combiner that extracts a part of the transmit power, (5) is a duplexer that separates the transmit and receive signals, and (6) is a combiner that mixes a part of the transmit power from the receive signal and the combiner (41). A mixer that produces a Doppler signal, (7) is an amplifier with a predetermined bandwidth, (8) is a detector that detects the Doppler signal, and (9) outputs a signal when the input signal exceeds a predetermined threshold. +1 (l is the detonation circuit that generates the detonation signal in response to the signal output by the comparator (91), fil+ is the safety device to maintain the safety of the warhead, and fi3 is the detonation circuit that receives the detonation signal and detonates. Note that the safety device αl) and the warhead a't are not included in the proximity fuze.

When a guided missile is launched in such a configuration, the transmitter (3) is connected to the coupler (41, duplexer +5).
1. When the target aircraft enters the beam of the antenna (1), the emitted signal corresponds to the relative speed of the guided flying object and the target aircraft. After receiving the Doppler shift, the antenna (
1) is received. The received signal is.

Through the duplexer (5) and at the mixer (6), a part of the signal of the transmitted output is taken out by the combiner (4).

The signals are mixed to become a Doppler signal, which is then amplified by an amplifier (7) and input to a detector (8), where it becomes a pulse signal and enters a comparator +91. The input pulse signal is compared with a predetermined threshold, and if the pulse signal exceeds this threshold, a signal is output. This signal is the detonator circuit fi [
I, where it is converted into a detonation signal and the safety device α]
) to the warhead (1) and detonate it.

[Problem to be solved by the invention]

Since the conventional f:neck operates if the magnitude of the received signal is greater than a predetermined value, there is a problem in that it tends to malfunction due to strong external interference waves. Also.

Since it always operates at a constant Doppler frequency, if the relative speed between the guided flying object and the target aircraft, that is, the Doppler frequency, is greater than the optimum value, it will operate after the target aircraft has passed, while if it is smaller than the optimum value, the target aircraft will The problem was that it activated before it passed.

This invention has been made in order to solve the above problems, and it is an object of the present invention to prevent malfunctions caused by external interference waves and to optimize the timing of the detonation operation of a proximity fuse.

[Means to solve the problem]

The proximity fuze of this invention applies frequency modulation to the signal to be transmitted so that its frequency changes over time, and when receiving the signal, the pulse width is changed by passing it through a Shita matted filter that matches this frequency modulation. In addition to aiming at compression, a pulse counting circuit is installed after the pulse pressure path, and a threshold value is set by using a means to perform pulse width discrimination before and after compression of the pulse width, and by utilizing the wide beam width of the antenna. death.

The device is equipped with means for changing this threshold value in accordance with the Doppler frequency.

[Effect]

In this invention, the signal to be transmitted is frequency modulated so that its frequency changes over time.

By passing the received signal through a matched filter suitable for one-frequency modulation, the pulse width is compressed, making it possible to increase the amplitude of the received signal. On the other hand, since the pulse width of the external interference wave is not compressed unless the same frequency modulation as the transmitted signal has occurred, it is possible to improve the SZJ ratio (signal to interference wave ratio) to the interference wave. Furthermore, by distinguishing between the pulse widths before and after pulse compression, it is possible to prevent malfunctions due to large-amplitude interference waves.

On the other hand, by setting the threshold value of the counting circuit provided after pulse compression low when the Doppler frequency sand is high, and conversely high when the Doppler frequency is low, it is possible to always operate at an appropriate position.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention.

(1) to α2 are exactly the same as the conventional proximity fuse.

+13 is a reference signal generator that generates an IF band reference signal.

The alpha core applies frequency modulation to the frequency of the reference signal so that it changes over time, and a dispersive filter that shapes the waveform to a predetermined pulse width increases the alpha frequency modulated reference signal to the transmission frequency. local oscillator for,
fiG is an up converter that combines the frequencies of the frequency-modulated reference signal and the signal from the local oscillator α to make the transmission frequency, and is an I in the IF band whose center frequency is the same as that of the reference signal.
F amplifier, aδ is the first detector that detects the IF amplified signal, +19 is the pulse width of the output signal of the first detector αa is equivalent to the pulse width of the transmission signal, and the amplitude is a predetermined value. The first pulse width discriminator outputs a signal when the value is greater than or equal to the value. The pulse width of the output signal of the second detector Qυ is equal to the pulse width after pulse compression, and the amplitude is determined by the first pulse width discriminator 1 as the pulse width. A second pulse width discriminator outputs a signal when the pulse width is higher than a threshold set by the amount of compression.

■ is a gate circuit that allows the output signal of the second pulse width discriminator ■ to pass only when there is an output signal of the first pulse width discriminator αg, and cuJ is the pulse compressed signal output from the matched filter ■ and the reference signal. A Doppler detector that mixes the basic fishing signal of generator a3 and generates a Doppler signal corresponding to the relative speed of the guided flying object and the target aircraft. It is a sand measuring circuit that has a threshold value that changes depending on the Doppler frequency output by the detector @, and outputs a signal when the count value exceeds this threshold value.

In addition, Fig. 2 shows the frequency modulation relationship of 20 dispersive filters, and (al and (b) in Fig. 3).
) indicate the pulse waveforms before and after pulse compression, respectively.

In the proximity fuse configured as described above, the reference signal output by the reference signal generator fi3 is subjected to frequency modulation whose frequency changes over time by the dispersive filter α4, and then shaped into a predetermined pulse width. Been,
Input to up converter αG and 8 local oscillators 11″3
The frequency is increased by the frequency of the signal. After this, the duplexer (6), power divider (
21 and is radiated into the air from antenna +11. The signal reflected by the target aircraft undergoes a Doppler shift corresponding to the relative speed between the guided flying object and the target aircraft, and is received again by the antenna (1), and is then received by the tI power divider 2),
It passes through the duplexer (6) and is added to the mixer (6) where it is mixed with the signal of the local oscillator α9 and the I
The signal is subjected to F-fold signal conversion, enters the IF amplifier αη, and is amplified. The signal amplified by the IF amplifier (171) is detected by the first detector α8.

becomes a pulse signal and passes through the first pulse width discriminator (at 19).

Its pulse width is equal to the transmitted pulse width, and

If the amplitude is greater than a predetermined value, a signal is output to the gate circuit. The other IF multiplied signal is input to the matched filter ■, where the pulse is compressed, and the amplitude is increased by the amount of pulse compression.
is input. , the pulse-compressed signal input to the second detector c21) is detected and input to the second pulse width discriminator. Is the pulse width of the input signal equal to the predetermined pulse width after pulse compression, and is its amplitude equal to or greater than the threshold set by the first pulse width discriminator (19) by the amount of pulse compression? 1. If both conditions are met, a signal is output to the gate circuit.Matched filter ■
Another output of the Doppler detector c! − is input,
Here, it is mixed with the reference signal of the reference signal generator a3, becomes a Doppler signal corresponding to the relative speed of the guided flying object and the target aircraft, and is sent to the counting circuit, which sets the threshold value of the counting circuit as a Doppler signal. When the Doppler frequency is high, it is set to be low, and when the Doppler frequency is low, it is set to be high. The output signal of the second pulse width discriminator
When there is an output signal of the pulse width discriminator α9.

It passes through the gate circuit ■, enters the counting circuit, where it is counted, and when it exceeds the threshold corresponding to the Doppler frequency, it outputs a signal to the detonation circuit αG, where it is converted to a detonation signal and passes through the safety device fiυ. Then send it to warhead a2 and detonate it.

〔Effect of the invention〕

As explained above, this invention applies frequency modulation to the frequency of the transmitted signal so that it changes over time, and when receiving it, it passes through a matched filter that is compatible with this frequency modulation, so that only the transmitted signal can be processed. It becomes possible to increase the amplitude and improve the S/J ratio with respect to external interference waves. Also.

Distinguish the pulse width before pulse compression and after pulse compression,
It is possible to prevent the device from operating when the pulse width is other than a predetermined pulse width.

Furthermore, by changing the threshold of the counting circuit according to the Doppler frequency that corresponds to the relative speed of the guide gongoplast and the target aircraft, it is possible to change the timing at which the proximity fuze is activated in accordance with the Doppler frequency, so that it can operate properly. become.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram explaining frequency modulation time characteristics of a transmission signal, FIG. 3 is a diagram showing pulse waveforms before and after pulse compression, and FIG. 4 is a diagram illustrating a conventional example. It is a figure showing the composition of the proximity fuze of. In the figure, (1) is the antenna, [2] is the power divider, (
31 is a transmitter, 141Fi coupler, (5) is a duplexer, (61 is a mixer, (7) is an amplifier, (8) is a detector, (91 is a comparator, αG is a detonation circuit, αl) is a safety device, (I3 is the warhead, α
3 is a reference signal generator, α4 is a dispersive filter,
α is local oscillator, ueFi up converter, +If
) ilF amplifier, apa and an are detectors, σ9 is a pulse width discriminator, anFi matched filter, gate gate circuit, □□□ Doppler detector, 25 is a counting circuit, Fig. 1 In the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] a signal generator that generates a reference signal in an intermediate frequency (IF) band; a means for applying frequency modulation to the output signal of the signal generator so that the frequency changes with time; and transmitting the signal as a transmission signal; I emits the above-mentioned transmission signal into the air, inputs the reflected signal from the target aircraft via the above-mentioned antenna, converts the signal into an IF signal, and amplifies it.
F signal converting means, a first detector for detecting the output signal of the IF signal converting means, and a compression device having characteristics suitable for the frequency modulation and compressing the pulse width of the output signal of the IF signal converting means. means, a second detector for detecting the output signal of the compression means, and a pulse width of the signal detected by the first detector and a pulse width of the signal detected by the second detector, respectively. first and second pulse width discriminators that output a predetermined signal only when the pulse width is a predetermined width and the amplitude thereof exceeds a predetermined level; and the output signal of the first pulse width discriminator is A gate circuit that allows the output signal of the second pulse width discriminator to pass only at certain times, and inputs the output signal of the signal generator and the output signal of the compression means to determine the relative speed of the guided flying object and the target aircraft. A Doppler detector that detects Doppler signals corresponding to A proximity fuze comprising means for generating a signal for operating a circuit.