JPH0225700A - Proximity fuse - Google Patents

Abstract

PURPOSE:To eliminate malfunction due to reflected wave from the surface of ground or sea as well as the saturation of a receiving system by a method wherein a variable attenuator is provided on a route from a directional coupler to the input side of first and second mixers while the attenuating amount of the variable attenuator is controlled by the output of an integrator through a function generator. CONSTITUTION:The output of an integrator 17 includes an information on a distance between a missile and the surface of ground or sea, which is outputted by a tracking loop, and, therefore, the receiving input into first and second mixers 5a, 5b by a reflected wave from the surface of ground or sea is provided with an attenuation in inverse proportion to the square of the distance between the missile and the surface of ground or sea by the effect of the variable attenuator 13 when the attenuating amount of the variable attenuator 13 is controlled by a function generator 20 so as to be in inverse proportion to the distance between the missile and the surface of ground or sea. However, the receiving strength of the reflected wave from the surface of ground or sea is in inverse proportion to the square of the distance and, therefore, receiving powers for the first and second mixers 5a, 5b by the reflected wave will never be changed by the employment of the variable attenuator 13. Accordingly, malfunction due to the reflected wave may be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is directed to a target such as an aircraft that is within the effective range of a warhead of a flying object such as a cannonball or a missile, and that is This relates to a proximity fuse that detects in which direction a target is present.

[Conventional technology]

Figure 1O is a diagram showing the configuration of a conventional proximity fuse shown in, for example, Japanese Utility Model Publication No. 62-3741. In Figure 15, (1) is an oscillator, and (2) is an output of this oscillator (1). (3) is a circulator that guides the output of the directional coupler (2) to the antenna (4), (5) is a mixer, (6) is a video amplifier, and (7) is a doppler. filter, (8) is a detector, (9) is a comparator,
(10) is the ignition circuit, and (11) is the threshold cold setting device.Next, the operation will be explained. antenna (4)
The signal transmitted by the antenna (4) is irradiated onto the target, and the reflected signal is received again by the antenna (4). Circulator (3
), mixed with a part of the output of the directional coupler (2) in the mixer (5), and amplified in the video amplifier (6).
This detector (8) passes through a Doppler filter (7) that allows only the Doppler frequency corresponding to the relative speed difference between the target and the projectile to pass through, and the amplitude is detected by the detector (8).
The comparator (9) compares the output of the detector (8) with the threshold set by the threshold setter (11), and when the output of the detector (8) is greater than the threshold, the ignition circuit (10) is activated. Activate it and explode the warhead of the flying body.

A conventional proximity fuse is configured as described above, and detects the Doppler frequency component due to the relative speed difference between the target and the projectile.
It is now working.

[Problem to be solved by the invention]

However, as mentioned above, since the transmission output is a single frequency, it is easy to discover that the enemy is emitting radio waves, and it is also easy to detect interference waves by using a Doppler filter (7
), no countermeasures can be taken. Furthermore, the operating range changes depending on the strength of the reflected power from the target.

There is a problem that it is difficult to match the effective range of the warhead, and if the projectile flies at low altitude, it may malfunction due to waves reflected from the ground or sea surface, or the receiving system may become saturated. There was a point, and it was not possible to detect in which direction the target was located when viewed from the projectile.

This invention was made to solve the above-mentioned problems, and it is difficult for the enemy to discover the use of radio waves, and it also makes it less susceptible to interference and has a wider range of operation. The objective is to obtain a proximity fuze that can be clearly set, eliminates malfunctions and saturation of the receiving system due to reflected waves from the ground or sea surface, and has the function of detecting the direction of the target.

[Means to solve the problem]

The proximity fuse according to the present invention widens one frequency band by modulating the transmitted wave with a spread spectrum code, and even if it is discovered by an enemy and is interfered with, the video amplifier of the received signal can be By correlating the output with the code 1 bit before and 1 bit after the modulation signal using a correlator, interference waves that are not modulated with the same code as the modulation code are despread and transmitted to the Doppler of one nearby fuze. Since it goes out of the filter band, it is made stronger against interference, and the operating range is centered around a distance corresponding to the round trip time of a radio wave that differs by only 1 bit from the modulation code, and the round trip of the radio wave of 1 bit before and after that. By making it possible to limit the distance range to a distance corresponding to time, and by changing the oscillation frequency of the voltage-controlled oscillator that drives the first and second code generators depending on the distance to the ground or sea surface, the above-mentioned distance range can be expanded. It changes according to the distance to the ground or sea surface, so that the above distance range is consistent with the effective range of the missile's warhead, and the signal of the reflected wave from the ground or sea surface Since the intensity is inversely proportional to the square of the distance between the projectile and the ground or sea surface, by using a variable attenuator whose attenuation is inversely proportional to the square of this distance, the received signal input to the mixer due to this reflected wave can be input to the ground or sea surface. Regardless of the distance to the sea surface - again. By comparing the intensities of the received signals obtained by the third and fourth antennas attached to the left and right sides of the body of the spacecraft, the left or right side of the target position as seen from the spacecraft can be determined. Information on which side the target exists on is obtained, and information on whether the target exists on either the lower or upper side is obtained from the codes generated by the first or second code generator.

By comparing which code has a larger received signal, the combination of left, right, lower, or upper determines the position of the target as seen from the aircraft, that is, in the plane perpendicular to the aircraft's axis. This makes it possible to detect in which quadrant the target is located.

[Effect]

In the proximity fuse of the present invention, in the downward direction of the projectile, the output of one oscillator is spread spectrum modulated by the output of a first 1-bit delay circuit that delays the output of the first spread spectrum code generator by 1 bit. Transmitted from the first antenna, and for the upward direction of the projectile, the output of the two oscillators is spread spectrum modulated by the output of the third 1-bit delay circuit, which delays the □ output of the second spread spectrum code generator by 1 bit. and the reflected signals from the target are received by the third and fourth antennas. The signal received by the third antenna is homodyne-detected by being mixed with a portion of the output of the oscillator in the first mixer. The detected output is amplified by the first video amplifier and then divided into four equal parts, each of which has a first video amplifier. Second. Third
and in the fourth correlator, the output of the first code generator;
The output of the second 1-bit delay circuit, which is delayed by 2 bits from this first code generator, is 2 bits + more than the first code generator.
The output of the ΔT delay circuit delayed by 8 T and the output of the fourth 1-bit delay circuit delayed by 2 bits from the second code generator are correlated, and the signal received by the fourth antenna is A mixer mixes the signal with a portion of the output of the oscillator, thereby performing homodyne detection. The detection output is amplified by the second video amplifier and then divided into three equal parts, each of which is divided into three parts. In the sixth and seventh correlators, the output of the second code generator, the output of the second 1-bit delay circuit that is two bits later than the first code generator, and the output of the second code generator that is two bits later than the second code generator. A correlation is taken with the delayed output of the fourth 1-bit delay circuit. The outputs of these first to seventh correlators are filtered through first to seventh Doppler filters through which only Doppler frequency band waves corresponding to a preset range of relative velocity difference between the target and the flying object can pass. The outputs thereof are respectively detected by the first to seventh detectors. A constant voltage is added to the outputs of the first and pole 5 detectors in first and second bias adders, respectively. The output of the third detector is compared with the output of the first bias adder indicated by -F in a first comparator, and after the output is integrated in an integrator, the output is compared with the output of the first bias adder, and then the output is integrated by an integrator. The variable attenuator controls the oscillation frequency of the voltage-controlled oscillator that drives the oscillator, and also drives the function generator, causing the variable attenuator to generate an attenuation amount that is inversely proportional to the square of the distance between the projectile and the ground or sea surface. The outputs of the first and second bias adders are compared with the outputs of the second and fourth and sixth and seventh detectors, respectively, in the second to fifth comparators of the signal detector. Each of the second to fifth comparators generates a detection signal when the outputs of the sixth and seventh detectors become larger than the outputs of the first and second bias adders, respectively. The trigger pulse generator generates a pulse when a detection signal is obtained from any one or more of the second to fifth comparators of the signal detector. In the signal comparators, the 2nd. 4th. The magnitudes of two of the outputs of the sixth and seventh detectors are compared to generate respective comparison signals. The quadrant determiner holds the above six comparison signals using the trigger pulse from the trigger pulse generator, and uses a combination of these held signals to judge the quadrant in which the target exists, and selects the first to first signals corresponding to this quadrant. Activate one of the four ignition circuits.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) is the oscillator, (2) is this oscillator (1
), a directional coupler for taking out part of the output of (4
, ) is the first wave that emits radio waves into the air below the flying object.
antenna, (4,) is the second antenna that emits radio waves into the air above the flying object, (4°) and (4,)
are the third and fourth receiving antennas attached to the left and right sides of the aircraft's fuselage.

(5,) and (55) are the first and second mixers, (6
, ) and (65) are the first and second video amplifiers, (
7,) to (7,) are first to seventh Doppler filters,
(8,) to (81) are the first to seventh detectors, (9,
) is the first comparator, (10,) to (10,l) are the first comparator
~4th ignition circuit, (12,) and (+2.) are the first
and a second modulator, (+3) is a variable attenuator for attenuating the output of the directional coupler (2), (14,) and (14,,) are the variable attenuator (13) and the directional coupler. vessel(
2) for distributing each output into two.
(+5.) to (15,) are the first to seventh correlators.

(+6.) and (16,) are the first and second bias adders (17) are integrators, (1g) is a voltage controlled oscillator,
(+9.) and (19h) are the first and second code generators, (20,) to (20,) are the first to fourth 1-bit delay circuits, (21) is the ΔT delay circuit, (23 ) is the signal detector, (24) is the trigger pulse generator, (25)
is a signal comparator, (26) is a quadrant judger, and (27) is a function generator.

Spread spectrum codes can be 1M series, Gold codes, etc., but all of them generate a high correlation output for a signal that is in phase with the own code, and generate a high correlation output for signals that are out of phase with other codes or codes that are out of phase by 1 bit or more. In this case, only an extremely low correlation output is generated. This invention uses this principle.

The output of the oscillator (1) is attenuated by a variable attenuator (13) via a directional coupler (2), and the output of the oscillator (1) is attenuated by a variable attenuator (13).
After modulating the transmission signal in the first modulator (12,) by the output of the first 1-bit delay circuit (20,), which is delayed by 1 bit from the output of the While transmitting as a radio wave by the antenna (4a) of 1,
The output of the third 1-bit delay circuit (20c), which is delayed by 1 bit from the output of the second code generator (19b), modulates the transmission signal in the second modulator (12h). Radio waves are transmitted upward by a second antenna (45).

Here, the first and second code generators (+9A) and (19h
) generate different codes, which will be referred to as a first code and a second code, respectively.

The reflected waves from the target are transmitted by the third and fourth antennas (4o) and (4d) attached to the left and right sides of the fuselage of the aircraft.
After being homodyne-detected by first and second mixers (5a) and (5b), respectively, the signals are amplified by first and second video amplifiers (6A) and (6h). 1st
The output of the video amplifier (6,) is sent to the first to fourth correlators (
+5. ) to (tS, ), the output of the first code generator (19,), the second 1-bit delay circuit (20h
), the output of the AT delay circuit (21), and the output of the fourth 1-bit delay circuit (20d), and the output of the second video amplifier (65) is correlated with the output of the AT delay circuit (21) and the output of the fourth 1-bit delay circuit (20d). (1
5,) to (15,), the output of the second code generator (19,) and the second 1-bit delay circuit (20h), respectively.
Correlation is taken with the output of the fourth 1-bit delay circuit (20d).

However, since the first correlator (15,) takes the correlation with the first code whose phase is one bit ahead of the transmitted signal modulated with the first code, its output is divided by receiver noise and interference. Only a signal is generated in which the transmitted signal, which has no correlation with the signal, is despread by the above-mentioned first code. After passing this signal through a Doppler filter (7a) and a detection n (8,),
By adding a constant bias with the bias adder (16,), an adaptive threshold can be set according to the radio wave environment inside and outside the proximity fuse.

In addition, in the second correlator (15,), correlation is taken using the first code that is l bit behind the transmitted wave modulated with the first code, so the first code that is l bit delayed from the transmitted wave is A strong correlation output is generated only when a reflected wave of a modulated wave from the target according to the first code appears in the range of 1 bit before and after . This signal contains a Doppler frequency corresponding to the relative velocity difference between the target and the projectile, so it is filtered by a Doppler filter (7
ゎ) and is detected by a detector (8b).

Furthermore, in the third correlator (15e), the correlation is taken by the first code that is delayed by 1 bit + Δ from the transmitted wave modulated by the first code, so the signal is delayed by 1 bit + 8 T from the transmitted signal. A strong correlation output is generated only when a reflected wave of a modulated wave by the first code appears in a range of 1 bit before and after the first code. FIG. 2 shows time and the first bias adder, the second .
This is a diagram showing the relationship between the output voltage of the third wave detector and the output voltage of the first bias adder (18,). is the third detector (
The output voltage of 8c), -, indicates the tracking distance. As shown in Figure 2, the third detector can obtain a correlation output at the farthest distance from the projectile, so the projectile flies at a low altitude and the reflected waves from the ground or sea surface are When obtained within the round-trip distance of radio waves corresponding to the range described above.

A correlated output will occur. Since this signal includes a Doppler frequency corresponding to the speed of the flying object, it passes through a Doppler filter (7e) and is detected by a detector 28 (8,), and then the first comparator (9c) detects the first bias. Adder (16
, ) is compared with the output of In the third correlator (15,), correlation is taken by the output of the ΔT delay circuit (21), so signals due to uncorrelated receiver internal noise, external interference waves, and uncorrelated transmitted signals are After being despread, the signal only in the passband of the Doppler filter (7c) is sent to the detector (
8, .), and is added to the output of the Doppler frequency component of the two reflected waves, and appears at the output of the detector (8c). Therefore, from the output of the first comparator (96), the internal noise of the receiver, the external interference signal component and the uncorrelated transmitted signal component are subtracted, and only the reflected signal component appears. This signal is refined by an integrator (17) and a voltage controlled oscillator (
+8) to control its oscillation frequency. The relationship between the input voltage and the output oscillation frequency of the voltage controlled oscillator (18) is as shown in Figure 3, so when the projectile is flying at a sufficiently high altitude, the third detector (8) ，
) is small, the output of the integrator (17) is OV, and the output oscillation frequency of the voltage controlled oscillator (18) is a corresponding frequency fL. However, when the projectile flies at a low altitude and produces an output at the third detector (8 degrees), which exceeds the output voltage of the first bias adder (+6.), the output voltage of the first bias adder (+6. The comparator (96) outputs the difference voltage between the two. This output voltage is integrated by an integrator (17).

Since the signal is input to the voltage controlled oscillator (18), its output frequency increases as shown in FIG. The first code generator (19°) is driven by this voltage controlled oscillator (18), so an increase in frequency means that the period of one bit becomes shorter, and the corresponding round-trip distance of the radio wave also decreases. The third detector (8c) shown in Figure 2C is shortened.
The output time width of
The output voltage of (o) decreases, and this voltage balances out at the point of tracking distance 2 shown in FIG. That is, the 74-voltage controlled oscillator (Hl), the first code generator (19,), the first
and second 1-bit delay circuit (20,) and (20b)
, ΔT delay circuit (21), third correlator (+5.), third Doppler filter (7e,), third detector (8e,
), the first comparator (9,), and the integrator (17) form a loop that tracks the reflected wave from the ground or sea surface input from the first video amplifier (6a),
This tracking distance will automatically change depending on the flight altitude of the projectile.

Incidentally, the output of the integrator (17) includes information on the distance between the projectile and the ground or sea surface due to the tracking loop. Therefore, by controlling the attenuation amount of the variable attenuator (13) by the function generator (27) so that it is inversely proportional to the square of the distance between the flying object and the ground or sea surface, the first and second mixers (5A ) and (5h) due to reflected waves from the ground or sea surface are attenuated in inverse proportion to the square of the distance between the flying object and the ground or sea surface by the function of the variable attenuator (13). Become. However, since the received intensity of reflected waves from the ground or sea surface is inversely proportional to the square of the distance, the use of the variable attenuator (13) reduces this reflection to the first and second mixers (56) and (5b). The power received by waves does not change depending on the distance between the flying object and the ground or sea surface.

Next, in the fourth correlator (tSa), a voltage controlled oscillator (18
) is correlated with a second code generated by a second code generator (19b) driven by a second code generator (19b). The fourth correlator (
15d), the correlation is taken using the second code that is 1 bit behind the transmitted wave modulated by the second code, so the signal from the target is within 1 bit before and after the second code that is 1 bit delayed from the transmitted wave. A strong correlation output is generated only when a reflected wave of a modulated wave with the second code appears. Since this signal includes a Doppler frequency corresponding to the relative velocity difference between the target and the projectile, it passes through a Doppler filter (7d) and is detected by a detector (8d). The fifth correlator (15,) takes the correlation with the second code whose phase is one pit ahead of the transmitted signal modulated with the second code, so its output is combined with the receiver noise and the interference signal. Only a signal is generated in which the uncorrelated transmitted signal is despread by the above-mentioned second code.

This signal is passed through a Doppler filter (7°) and a detector (8o).
After passing through the signal, a constant bias is added by the second bias adder (16,), thereby making it possible to set an adaptive threshold according to the radio wave environment inside and outside the proximity fuse.

In addition, in the sixth correlator (+S+), correlation is taken using the first code that is 1 bit delayed from the transmitted wave modulated by the first code, so the first code that is 1 bit delayed from the transmitted wave is A strong correlation output is generated only when a reflected wave of a modulated wave of the first code from the target appears in the range of 1 bit before and after. This signal contains a Doppler frequency corresponding to the relative velocity difference between the target and the projectile, so it is filtered by a Doppler filter (7
, ) and is detected by a detector (8,).

Furthermore, in the first correlator (15□), correlation is taken using the second code that is delayed by 1 bit from the transmitted wave modulated by the second code, so the second code that is delayed by 1 bit from the transmitted wave is A strong correlation output is generated only when the reflected wave of the modulated wave of the second code from the target appears in the range of 1 bit before and after. This signal contains a Doppler frequency corresponding to the relative velocity difference between the target and the projectile, so it is filtered by a Doppler filter (7K
) and is detected by the detector (8□).

FIG. 4 is a diagram showing details of the signal detector (23), in which A and D are the outputs of the first and second bias adders (16,) and (16,), B, C, E and F are second;
4th. 6th and 7th detectors (g,), (g,),
These are the outputs of (a,) and (81), and (9b) to (9
o) are the second to fifth comparators. Second comparator (9h
), the output A of the first bias adder (+6.) and the second
The output B of the detector (81) is compared. In the second correlator (15h), correlation is taken by the output of the second 1-bit delay circuit (20,,), so uncorrelated internal receiver noise, external interference waves, and two-phase shifts are detected. The signals caused by the modulated wave of the first code and the modulated wave of the second code are despread, and the signal of only the pass band of the Doppler filter (7h) is sent to the detector (8b), and the Doppler filter from the target is sent to the detector (8b). It is added to the output of the frequency component and appears in the output of one detector (8, .). Therefore, from the output of the second comparator (9ゎ), the internal noise of the receiver, the external interference signal component, and the uncorrelated transmitted signal component are subtracted, and only the target signal component appears, and the detected signal G is obtained. It will be done.

In the third comparator (9e), the first bias adder (tS
, ) and the output C of the fourth detector (8d) are compared. In the fourth correlator (15d), correlation is taken by the output of the fourth 1-bit delay circuit (20,), so uncorrelated internal receiver noise, external interference, and the first code modulated wave The signal generated by the modulated wave of the second code with a two-phase shift is despread, and the signal of only the passband of the Doppler filter (7d) is sent to the detector (8d), which detects the signal due to the Doppler frequency component from the target. The output is added to the detector (8,
) appears in the output.

Therefore, from the output of the third comparator (9c), the internal noise of the receiver, the external interference signal component, and the uncorrelated transmitted signal component are subtracted, and only the target signal component appears, and the detected signal H is obtained. It will be done. The fourth comparator (9,) outputs the output of the second bias adder (16b) and the sixth detector (8.
) are compared. In the sixth correlator (15f), the correlation is taken by the output of the second 1-bit delay circuit (20b), so uncorrelated internal receiver noise, external interference waves, and the first signal with a one-phase shift are detected. The modulated wave with the code of It appears in the output of the detector (8r). Therefore, the fourth
From the output of the comparator (96), the internal noise of the receiver, the external interference signal component, and the uncorrelated transmitted signal component are subtracted, and only the target signal component appears, and the detection signal I is obtained. In the fifth comparator (9o), the output of the second bias adder (16b) and the output F of the seventh detector (8□)
are compared. In the seventh correlator (15,), the correlation is taken by the output of the fourth 1-bit delay circuit (20,). The signal due to the modulated wave or the modulated wave of the second code with a two-phase shift is despread and passed through the Doppler filter (7,).
A signal of only the passband of is sent to the detector (81), added to the output of the Doppler frequency component from the target, and appears at the output of the detector (8,). Therefore, the fifth comparator (9
The output of ゜) is obtained by subtracting the receiver's internal noise, external interfering signal components, and uncorrelated transmitted signal components.

Purely only the target signal component appears, and a detection signal J is obtained.

Next, FIG. 5 is a diagram showing details of the trigger pulse generator (24), in which (28) is an OR circuit, and (29) is a pulse generator. 2nd to 5th comparators (9ゎ) to (9o
) If a detection signal is obtained in one or more of the above, OR
The circuit (28) activates the pulse generator (29) and generates a pulse K with a constant pulse width. In addition, in the second correlator (isb), the third correlator (15,)
Since the correlation is taken by the first code before T,
The distance range in which the second detector (8b) can obtain a correlation output also varies depending on the flight altitude, and as shown in Figure 2, it is wider than the correlation output range of the third detector (8°). is also inside. As a result, even if the flying object flies at a low altitude, the second detector (8
, ) becomes larger, the second comparator (9h) no longer generates the detection signal G by mistake, and only when the target appears within the distance between the projectile and the ground or sea surface, the second comparator (9h) An output will be obtained from the wave detector (8h). Similarly, in the sixth correlator (15,), correlation is taken using the first code that is 8T earlier than the third correlator (15c), so the sixth correlator (8r) The distance range in which the correlation output can be obtained also varies depending on the flight altitude, and is located inside the correlation output range of the third detector (8°) as shown in FIG. As a result, even if you try to fly,
The sixth detector (8,) is detected by the reflected wave from the ground or sea surface.
The output of the fourth comparator (9d) becomes larger, and the fourth comparator (9d) no longer generates the detection signal I by mistake, and only when the target appears within the distance between the projectile and the ground or sea surface, the sixth comparator
An output is obtained from the detector (8,).

Next, FIG. 6 is a cross-section perpendicular to the aircraft axis, seen from the rear of the aircraft, where the y-axis represents the left-right axis and the Z-axis represents the vertical axis. The quadrant defined by the positive direction of the y-axis, that is, the right direction, and the positive direction of the Z-axis, that is, the lower part, is defined as the first quadrant, and hereinafter, quadrants ①, ②, and Ⅳ are defined as shown in the figure. In the figure, I represents the body of the flying object, and 46) to (4d) represent the first to fourth anchors. In addition, FIG. 7 shows the first to fourth antennas (4,) to
This shows the radiation pattern according to (4d), and in Figure 2, PA is the pattern in which the signal modulated with the first code is radiated from the first antenna (48) to the lower part of the body of the projectile, and Pa is This is a pattern in which the second antenna (4h) radiates a signal modulated with the second code to the upper part of the fuselage, and Pc is the third antenna installed on the left side of the fuselage.
The reception pattern by the antenna (4c) is Pa is the reception pattern by the fourth antenna (4d) attached to the right side of the fuselage, the PR is transmitted downward by the first antenna (46), and the reception pattern is transmitted by the fourth antenna (46) on the right side. 4d), i.e., beam I is transmitted downward by the first antenna (46), and is transmitted downward by the third antenna (46) on the left side.
The PG transmits the combined transmission/reception pattern received at ゜゜, that is, beam ■, upwards using the second antenna (4b), and the combined transmission and reception pattern received by the third antenna (4゜) on the left side, ie, beam ■. ,P,1 is transmitted upward by the second antenna (4h), and the fourth antenna on the right (4d)
This shows the combined transmission and reception pattern received at , that is, beam ■.

By the way, the output of the second detector (85) is the signal received by the third antenna on the left (4 degrees) correlated with the first code, so it corresponds to the output of beam ■. Fourth
The output of the detector (8d) is sent to the third antenna on the left (4c).
) is correlated with the second code, so it corresponds to the output of the beam ■, and the signal received by the sixth detector (8,
) is the signal received by the fourth antenna (4d) on the right side correlated with the first code, so it corresponds to the output of beam (2).

The output of the seventh detector comb) is the output of the fourth antenna on the right (fourth detector comb).
, 1), which is correlated with the second code, corresponds to beam (2).

FIG. 8 is a diagram showing details of the signal comparator (25), and in the figure B, C, E and F are the second. 4th. These are the outputs of the sixth and seventh detectors (8,,), (ga), (gr) and (81), and (9,) to (9k) are the sixth to it comparators. In the sixth comparator (9r), the second detector (
The output C of the fourth detector (86) is higher than the output B of the fourth detector (86).
is larger, a high-level comparison signal M is generated. The seventh comparator (9t) generates a high-level comparison signal N when the output E of the sixth detector (8υ) is larger than the output B of the second detector (8w). 8th
The comparator (9h) generates a high-level comparison signal 0 when the output F of the seventh detector (8,) is larger than the output B of the second detector (8b). .

In the ninth comparator (9,), when the output E of the sixth detector (8,) is larger than the output C of the fourth detector (L), the comparison signal P becomes high level. The 10th comparator (9J) generates a high-level comparison signal when the output F of the seventh detector (8t) is larger than the output C of the fourth detector (84). In the 11th comparator (9k) that generates Q, a high level comparison is made when the output F of the seventh detector (81) is larger than the output E of the sixth detector (8F). Also generates signal R. FIG. 9 is a diagram showing details of the quadrant determiner (26), and M-R in FIG. 1 indicates the 6th to 11th comparators (9,) to (9k) shown in FIG.
7 shows a comparison signal which is the output of the pulse generator (29) shown in FIG.
(30,) to (30r) are the first to sixth retainers, (
31°) to (31,) are the first to sixth inverters, (32
, ) to (32,) are the first to fourth AND circuits. The first to sixth retainers, (30,) to (30r) are the input signals M of each retainer when the trigger pulse K is input.
.about.R are each at a high level, each of the above-described signals generates a signal that remains at a high level only for a time corresponding to the pulse width of the pulse. In addition, the first to sixth inverters (31,) to
(3b) generates a low level output when each input is at a low level, and generates a high level output when each input is at a low level.

Next, the first to fourth AND circuits (32,) to (32d) each generate a high-level judgment signal S-■ only when all three inputs thereof are at high level, and The ignition circuits (10,) to (io,) of No. 4 are activated.

Here, if a target exists in the second quadrant, for example, the signal from the beam (ii) is received more strongly than the signals from the beams (i) to (ii). That is, the second. 4th. Among the outputs of the sixth and seventh detectors (gb), (gd), (g+) and (8□), the output of the sixth detector (8υ) is the largest. Therefore, the signal comparator (25) , the outputs of the seventh and ninth comparators (9□) and (9υ become high level, and the first
The output of the first comparator (9k) is low level. Among these three signals, the seventh and ninth comparators (91) and (
The output of 9υ is sent to the first AND circuit (3
2,), and the output of the eleventh comparator (9k) is inverted from low level to high level in the first inverter (31,) and input to the first AND circuit (32,). Therefore, all three inputs of the first AND circuit (32,) become high level, and this output also becomes high level, so that the first ignition circuit (10,) is activated.

However, the output of the seventh comparator (9K) is the output of the third inverter (9K).
31c) and becomes low level, the second A
The output of the ND circuit (32b) does not become high level and the second ignition circuit (10h) does not operate. Furthermore, the output of the ninth comparator (9I) is inverted by the fifth inverter (31,) and input to the third AND circuit (32,), which makes the output low level. Therefore, the third ignition circuit (IOJ does not operate. Furthermore, the 1t comparator (9k
) output from the fourth AND circuit (32,
), so the fourth ignition circuit (+0.1) is also not activated, that is, when a target exists in the first quadrant, only the first ignition circuit (10,) is activated.

Similarly, when the target exists in the 2nd, 2nd, or 4th quadrant, the 2nd... Third or fourth ignition circuit (
10h) (10,) or (10,) will be activated and the direction in which the target is present can be identified.

In addition.

The second and fourth 1-bit delay circuits delay the outputs of the first and third 1-bit delay circuits by 1 bit, but the spread spectrum codes of the first and second code generators are delayed by 2 bits. It would be better if you could delay it.

In the above embodiment, the variable attenuator (13) was provided between the directional coupler (2) and the distributor (14,);
between the modulator (12,) and the antenna (4,), between the modulator (12h) and the antenna (4b), or between the mixer (5,) (5 ,)
It is sufficient if it is provided in the path from the directional coupler (2) to the input of the mixer (58) (5b), such as between the input end of the antenna (4,) and the antenna (4,). Effects] As described above, according to this invention, since the transmitted waves are spread spectrum, the transmission power density per unit frequency band can be kept low, making it difficult for the enemy to discover. Even if a proximity fuze is received, the correlation is taken inside the proximity fuze, so it will not be affected by interference from an enemy who does not know this modulation code, and furthermore, the effective target detection range of the proximity fuze is 1 bit smaller than the transmitted modulation code. Since the round-trip distance of radio waves is kept within the distance corresponding to the phase of one bit before and after the delayed phase, the target detection range can be matched with the effective range of the warhead, and the target object can fly at a low altitude. In this case, the oscillation frequency of the voltage controlled oscillator (18) changes according to the altitude, and the distance of the reflected wave from the ground or sea surface can be automatically tracked, and the effective target detection range can be changed from the ground or the sea surface. Since it can be set smaller than the distance to the sea surface, malfunctions due to reflected waves from the ground or sea surface can be prevented, and the variable attenuator (13) can be used to prevent changes in the distance between the flying object and the ground or sea surface. Since the received signal and input power to the mixer are constant due to reflected waves from the ground or sea surface, saturation of the receiving system can be prevented, the dynamic range of the receiving system can be small, and the target can be easily hit. It has the effect of being able to identify in which direction it exists when viewed from the body.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a proximity fuse according to an embodiment of the present invention, and FIG. 2 is a diagram showing a time and first bias adder and a second bias adder.
FIG. 3 is a diagram showing the relationship between the input voltage and output oscillation frequency of the voltage controlled oscillator, FIG. 4 is a diagram showing the configuration of the signal detector, and FIG. The figure is a diagram showing the configuration of the pulse generator, and Figure 6 is a cross-sectional view of the projectile, showing the definitions of the r-th to IV-th quadrants and showing the positions of the first to fourth antenna installations. , FIG. 7 shows transmission patterns by the first to fourth antennas. Figure 8 is a diagram showing the configuration of a signal comparator, Figure 9 is a diagram showing the configuration of a quadrant judger, and Figure 10 is a diagram showing the configuration of a conventional proximity fuse. be. In the figure, (1) is an oscillator, (2) is a hexagonal coupler (
4) is the antenna, (5) is the mixer, (6) is the video amplifier, (7) is the Doppler filter, (8) is the detector 2 (9)
is a comparator, (10) is an ignition circuit, (12) is a modulator, (13) is a variable attenuator, (14) is a distributor, (
15) is a correlator, (16) is a bias adder, (1
7) is an integrator, (18) is an electric pressure controlled oscillator, (1
9) is a code generator, (20) is a 1-bit delay circuit,
(21) is a ΔT delay circuit, (23) is a signal detector,
(24) is a trigger pulse generator, (25) is a signal comparator, (26) is a quadrant judger, (27) is a function generator, (28) is an OR circuit, (29) is a pulse generator, (
30) is a retainer, (31) is an inverter, and (32) is an AND circuit. In FIG. 1, the same or corresponding parts are designated by the same reference numerals.

Claims (2)

[Claims] (1) a voltage controlled oscillator; a first code generator that is driven by the output of the voltage controlled oscillator and generates a spread spectrum code; and a first code generator that generates a spread spectrum code by delaying the output of the first code generator by one bit. 1 1-bit delay circuit, and the first 1-bit delay circuit
A second 1-bit delay circuit generated by further delaying the output of the 1-bit delay circuit by 1 bit, and a ΔT delay generated by delaying the output of the second 1-bit delay circuit by a minute time ΔT of 1 bit or less. a circuit, an oscillator that generates a transmission signal, a directional coupler that branches a part of the output of the oscillator, a first divider that divides the output of the directional coupler into two, and the first distribution a first modulator that spread-modulates one output of the transmitter with the output of the first 1-bit delay circuit; a second code generator that is driven by the output of the voltage controlled oscillator and generates a spread spectrum code different from the first code generator; A third 1-bit delay circuit that generates the output by delaying it by 1 bit, a fourth 1-bit delay circuit that generates the output by further delaying the output of the third 1-bit delay circuit, and the first distributor. a second modulator that spread-modulates the other output with the output of the third 1-bit delay circuit; and a second modulator that transmits the output of the second modulator toward the target, which is attached to the upper part of the fuselage of the flying object. a second antenna; a third antenna attached to the left side of the fuselage of the flying object that receives radio waves transmitted in the target direction by the first and second antennas and reflected from the target; and the directional coupling. a second divider that divides a part of the output of the oscillator branched by the oscillator into two; a first divider that mixes the output of the third antenna and one output of the second divider;
a first video amplifier that amplifies the output of the first mixer; and a first correlator that correlates the output of the first video amplifier with the output of the first code generator. , a second correlator that correlates the output of the first video amplifier and the output of the second 1-bit delay circuit; and a correlation between the output of the first video amplifier and the output of the ΔT delay circuit. a third correlator that correlates the output of the first video amplifier with the output of the fourth 1-bit delay circuit; a fourth antenna attached to the right side of the fuselage of the flying object that receives radio waves transmitted in the direction and reflected from the target; an output of the fourth antenna and the other output of the second distributor; a second mixer for mixing the second mixer; a second video amplifier for amplifying the output of the second mixer; and a second video amplifier for correlating the output of the second video amplifier with the output of the second code generator. a sixth correlator that correlates the output of the second video amplifier with the output of the second 1-bit delay circuit; and a sixth correlator that correlates the output of the second video amplifier with the output of the second one-bit delay circuit; a seventh correlator that takes a correlation with the output of the 1-bit delay circuit; and a first correlator that inputs the outputs of the first to seventh correlators through first to seventh Doppler filters, respectively.
- a seventh detector, a first bias adder that adds a constant bias voltage to the output of the first detector, and a second bias adder that adds a constant bias voltage to the output of the fifth detector.
a bias adder, a first comparator that compares the output of the first bias adder and the output of the third detector, and a first comparator that integrates the output of the first comparator to control the voltage. An integrator that controls the oscillation frequency of the oscillator compares the output of the first bias adder with the outputs of the second and fourth detectors, and compares the output of the first bias adder with the output of the second and fourth detectors. second and third comparators that respectively generate detection signals when the outputs of the second and fourth detectors are large; the outputs of the second bias adder; and the outputs of the sixth and seventh detectors; a signal detector comprising a fourth and a fifth comparator, each of which generates a detection signal when the outputs of the sixth and seventh detectors are larger than the output of the second bias adder; , a trigger pulse generator that generates a trigger pulse when a detection signal is obtained from any one or more of the second to fifth comparators of the signal detector;
A signal comparator consisting of sixth to eleventh comparators that compare two outputs of the sixth and seventh detectors, and a quadrant in which the target exists is determined based on the comparison result of the signal comparator. Using the quadrant determiner and the above quadrant determiner, the I,
A proximity fuze comprising first to fourth ignition circuits that are respectively activated when it is determined that a target exists in the II, III or IV quadrant. (2) A variable attenuator is provided in the path from the directional coupler to the inputs of the first and second mixers, and the amount of attenuation of the variable attenuator is controlled by the output of the integrator via a function generator. A proximity fuse according to claim (1), characterized in that: