JPH0756437B2 - Proximity fuze - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is directed to a target such as an aircraft falling within the effective range of a warhead of a projectile such as a shell or missile and seen from the projectile. It relates to a proximity fuze that detects in which direction the target is present.

[Conventional technology]

FIG. 9 is a diagram showing the configuration of a conventional close fuze shown, for example, in Japanese Utility Model Publication No. 62-3741. In FIG. 9, (1) is an oscillator and (2) is an output of the oscillator (1). A directional coupler for extracting a part, (3) a circulator for guiding the output of this directional coupler (2) to an antenna (4), (5) a mixer, (6) a video amplifier, (7) a Doppler filter, (8) is a detector, (9) is a comparator, (10) is an ignition circuit, and (11) is a threshold setting device.

Next, the operation will be described. The signal transmitted from the antenna (4) is applied to the target, and the reflected signal is received again by the antenna (4), passes through the circulator (3),
After being mixed with a part of the output of the directional coupler (2) in the mixer (5) and amplified by the video amplifier (6), only the Doppler frequency corresponding to the relative speed difference between the target and the flying object is passed. The amplitude is detected by the wave detector (8) after passing through the Doppler filter (7). The output of this detector (8) is compared with the threshold set by the threshold setter (11) by the comparator (9), and when the output of the detector (8) is larger than the threshold, the ignition circuit (10)
To fire the projectile's warhead.

The conventional proximity fuze is configured as described above, detects the Doppler frequency component due to the relative velocity difference between the target and the flying object,
It is working.

[Problems to be Solved by the Invention]

However, since the transmission output has a single frequency as described above, it is easy to find that the radio wave is emitted to the enemy side, and the frequency of the range that passes through the Doppler filter (7) as it is even for the interfering wave. In that case, you cannot have any countermeasures. Furthermore, since 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 in which direction the target exists from the perspective of the flying object. It was impossible to detect.

The present invention has been made in order to solve the above problems, and it is possible to make it difficult for an enemy to discover the use of radio waves and to be less susceptible to interference, and to clarify its operating range. The purpose is to obtain a proximity fuze that can be set and has the function of detecting the direction of existence of the target.

[Means for Solving the Problems]

The proximity fuze according to the present invention widens the frequency band by modulating a transmission wave with a spread spectrum code to make it difficult for the enemy side to find the output wave, and even in the unlikely event of interference, the output of the video amplifier of the reception signal is increased. By correlating with the code one bit before and one bit after the modulation signal by the correlator, the interfering wave that is not modulated with the same code as the modulation code is despread and out of the Doppler filter band of this proximity fuze. Therefore, in addition to being strong against interference, the operating range corresponds to the round trip time of the radio wave by 1 bit before and after the center of the distance equivalent to the round trip time of the radio wave which is deviated from the modulation code by 1 bit. To be able to limit to the distance range,
The above range was designed to match the effective range of the warhead of the projectile, and was obtained by the third and fourth antennas attached to the left and right sides of the fuselage's fuselage. By comparing the received signal intensities, information on which of the left and right sides the target exists from the position of the target seen from the flying object is obtained, and which side, lower or upper, the target exists. Regarding the information as to whether or not to do so, by comparing which of the codes generated by the first or second code generator the received signal is larger, the left or right or the lower or upper combination is obtained. , The position of the target as seen from the flying body, that is,
It is possible to detect in which quadrant the target exists in the plane orthogonal to the axis of the flying object.

[Work]

In the proximity fuze of the present invention, in the downward direction of the flying object, the output of the oscillator is spread-spectrum modulated by the output of the first 1-bit delay circuit which is delayed by 1 bit from the output of the first spread-spectrum code generator. The signal is transmitted from the first antenna, and in the upward direction of the flying object, the output of the oscillator 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. Then, the signals are transmitted from the second antenna, and the reflected signals of these 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 part of the output of the oscillator by the first mixer. The detected output is amplified by the first video amplifier and then divided into three equal parts, and the output of the first code generator is output from the first code generator in the first, second and third correlators, respectively. The signal received by the fourth antenna is correlated with the output of the second 1-bit delay circuit delayed by 2 bits and the output of the fourth 1-bit delay circuit delayed by 2 bits from the second code generator. Is mixed with a part of the output of the oscillator in the second mixer to be homodyne detected. The detected output is amplified by the second video amplifier and then divided into three equal parts, and the output of the second code generator and the output from the first code generator are respectively divided into fourth, fifth and sixth correlators. The output of the second 1-bit delay circuit delayed by bit and the output of the fourth 1-bit delay circuit delayed by 2 bits from the second code generator are correlated. The outputs of these first to sixth correlators pass through first to sixth Doppler filters, through which only Doppler frequency band waves corresponding to the preset relative velocity difference range between the target and the flying body can pass, The outputs are detected by the first to sixth detectors, respectively. A constant voltage is added to the outputs of the first and fourth detectors in the first and second bias adders, respectively. The outputs of the first and second bias adders are compared with the outputs of the second and third and fifth and sixth detectors, respectively, in the first to fourth comparators of the signal detector to obtain the second and third detectors. When the outputs of the third and fifth and sixth detectors are larger than the outputs of the first and second bias adders, respectively, the first to fourth comparators respectively generate detection signals. The trigger pulse generator generates a trigger pulse when a detection signal is obtained from any one or more of the first to fourth comparators of the signal detector. In the signal comparator, the second to the fifth comparators are used.
The magnitudes of the two outputs of the outputs of the third, fifth, and sixth detectors are compared with each other to generate comparison signals.
The quadrant determiner holds the above-mentioned six comparison signals by the trigger pulse from the trigger pulse generator, determines the quadrant in which the target exists by the combination of these hold signals, and determines the quadrants corresponding to the quadrants. One of the ignition circuits of

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, (1) is an oscillator, (2) is a directional coupler for extracting a part of the output of this oscillator (1),
(4a) is a first antenna that radiates radio waves in the air below the flying object, (4b) is a second antenna that radiates radio waves in the air above the flying object, (4c) and (4d) ) Is the third and fourth antennas for reception mounted on the left and right sides of the body of the flying body, (5a) and (5b) are the first and second mixers, (6a) and (6b) are First and second video amplifiers, (7a) to (7f) are first to sixth Doppler filters, (8a) to (8f) are first to sixth detectors, (10a) to
(10b) is the first to fourth ignition circuits, (12a) and (12b)
Are first and second modulators, and (14a) and (14b) are first for dividing the respective outputs of the directional coupler (2) into two.
And a second distributor, (15a) to (15f) are first to fifth correlators, (16a) and (16b) are first and second bias adders, and (19a) and (19b) are First and second code generators, (20a) to (20d) are first to fourth one-bit delay circuits, (22) is a clock oscillator, (23) is a signal detector,
(24) is the trigger pulse generator, (25) is the signal comparator,
(26) is a quadrant determiner.

As the spread spectrum code, M-sequence, Gold code, etc. can be considered, but in all cases, a high correlation output is generated for a signal whose phase coincides with its own code, and it is converted to another code or a code whose phase is shifted by 1 bit or more. On the other hand, only extremely low correlation output is generated. The present invention uses this principle.

After modulating the transmission signal in the first modulator (12a) by the output of the first 1-bit delay circuit (20a) which is delayed by 1 bit from the output of the first code generator (19a), let's fly. Transmit down the body with the first antenna (4a).

On the other hand, 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), causes the second
In the modulator (12b), the transmission signal is modulated, and the radio wave is transmitted by the second antenna (4b) in the upward direction of the flying object.

Here, it is assumed that the first and second code generators (19a) and (19b) generate different codes, and the first code,
It will be referred to as the second code.

The reflected waves from the target are received by the third and fourth antennas (4c) and (4d) mounted on the left and right sides of the body of the flying body, and the first and second mixers (5a) and (5
After homodyne detection in b), it is amplified in the first and second video amplifiers (6a) and (6b). The output of the first video amplifier (6a) is output from the first to third correlators (15a) to (15).
In c) the output of the first code generator (19a) respectively,
The output of the second 1-bit delay circuit (20b) and the output of the fourth 1-bit delay circuit (20d) are correlated, and the output of the second video amplifier (6b) is the fourth to sixth correlators. (15d)
To (15f), the output of the second code generator (19b), the output of the second 1-bit delay circuit (20b), and the fourth output, respectively.
The output of the 1-bit delay circuit (20d) is correlated.

However, in the first correlator (15a), the correlation between the first and the code, which is one bit ahead of the transmission signal modulated by the first code, is obtained, so that the output is the receiver noise and the interfering signal. A transmission signal that is not correlated with is only a signal that is despread by the above-mentioned first code. After passing this signal through the Doppler filter (7a) and the detector (8a), a constant bias is added by the first bias adder (16a), so that the adaptive threshold according to the radio environment inside and outside the close fuze can be obtained. Can be set.

Further, in the second correlator (15b), the correlation is obtained by the first code which is delayed by 1 bit from the transmission modulated by the first code, so that before and after the first code which is delayed by 1 bit from the transmitted wave. A strong correlation output is generated only when the reflected wave of the modulated wave of the first code from the target appears in the range of 1 bit. Since this signal contains the Doppler frequency corresponding to the relative speed difference between the target and the flying object, the Doppler filter (7
Passes b) and is detected by the detector (8b). FIG. 2 is a diagram showing the relationship between time and the output voltage of the first bias adder and the second detector. In the figure, a is the output voltage of the first bias adder (16a), and b is the output voltage. The output voltage of the second detector (8b) is shown.

Next, in the third correlator (15c), correlation is obtained with the second code generated by the second code generator (19b) driven by the clock oscillator (22). Third correlator (15c)
Then, since the correlation is obtained by the second code that is delayed by 1 bit from the transmission wave modulated by the second code,
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 one bit before and after the second code delayed by the bit. Since this signal contains the Doppler frequency corresponding to the relative velocity difference between the target and the flying object, it passes through the Doppler filter (7c) and is detected by the detector (8c).
Is detected by. The fourth correlator (15d) correlates with the second code whose phase is one bit ahead of the transmission signal closely transmitted by the second code, so that its output is the receiver noise and the interfering signal. Only uncorrelated transmission signals are despread by the above second code. After passing this signal through the Doppler filter (7d) and the detector (8d), a constant bias is added by the second bias adder (16b) to obtain an adaptive threshold according to the radio environment inside and outside the close fuze. Can be set.

Further, in the fifth correlator (15e), since the correlation is obtained by the first code delayed by 1 bit from the transmission wave modulated by the first code, the correlation of the first code delayed by 1 bit from the transmission wave is obtained. A strong correlation output is generated only when the reflected wave of the modulated wave of the first code from the target appears in the range of 1 bit before and after. Since this signal contains the Dopplas frequency corresponding to the relative velocity difference between the target and the flying object, it passes through the Doppler filter (7e) and is detected by the detector (8e).

Further, in the sixth correlator (15f), the correlation is obtained by the second code which is delayed by 1 bit from the transmission wave modulated by the second code, so that before and after the second code which is delayed by 1 bit from the transmission wave. 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. Since this signal contains the Doppler frequency corresponding to the relative speed difference between the target and the flying object, the Doppler filter (7
After passing through f), it is detected by the detector (8f).

FIG. 3 is a diagram showing the details of the signal detector (23), in which A and D are the outputs of the first and second bias adders (16a) and (16b), and B, C, E And F are outputs of the second, third, fifth and sixth detectors (8b), (8c), (8e) and (8f), and (9a) to (9d) are first to fourth. Is a comparator.
In the first comparator (9a), the first bias adder (16a)
Output A of the second detector (8b) is compared with the output A of the second detector (8b).
In the second correlator (15b), the second one-bit delay circuit (20
Since the output of b) is used for correlation, uncorrelated receiver internal noise, external interfering waves, phase-shifted first-code modulated waves, and second-code modulated signals The signal in the pass band of the Doppler filter (7b) is despread, is sent to the detector (8b), is added to the output of the Doppler frequency component from the target, and appears at the output of the detector (8b). Therefore, in the output of the first comparator (9a), the internal noise of the receiver, the external interference signal component and the uncorrelated transmission signal component are subtracted, and only the target signal component appears, and the detection signal G is obtained. can get. In the second comparator (9b), the output A of the first bias adder (16a) and the third detector (8
The output C of c) is compared. In the third correlator (15c), the correlation is obtained by the output of the fourth 1-bit delay circuit (20d). Therefore, uncorrelated receiver internal noise, external interference wave, and modulation of the first code The wave or the signal due to the modulated wave of the second code with a phase shift is despread, and the signal only in the pass band of the Doppler filter (7c) is sent to the detector (8c).
It is added to the output of the Doppler frequency component from the target and appears at the output of the detector (8c). Therefore, the output of the second comparator (9b) is subtracted from the internal noise of the receiver, the external interference signal component and the uncorrelated transmission signal component, and only the target signal component appears, and the detection signal H can get. In the third comparator (9c), the second bias adder (16
The output D of b) and the output E of the fifth detector (8e) are compared. In the fifth correlator (15e), the correlation is obtained by the output of the second 1-bit delay circuit (20b). Therefore, uncorrelated receiver internal noise, external interfering waves, and phase-shifted first The signal due to the modulated wave of the code of No.2 or the modulated wave of the second code is despread, and the signal of only the pass band of the Doppler filter (7e) is sent to the detector (8e) and output by the Doppler frequency component from the target. Is added and appears in the output of the detector (8e). Therefore, the output of the third comparator (9c) is subtracted from the internal noise of the receiver, the external interference signal component and the uncorrelated transmission signal component, and only the target signal component appears, and the detection signal I can get. The fourth comparator (9d) compares the output D of the second bias adder (16b) with the output F of the sixth detector (8f). 6th correlator (15f)
Since the correlation is obtained by the output of the fourth 1-bit delay circuit (20d), uncorrelated receiver internal noise, external interfering wave, first code modulated wave, phase-shifted first Two
The signal due to the modulated wave of the code is despread, and the signal only in the pass band of the Doppler filter (7f) is sent to the detector (8f), and is added to the output due to the Doppler frequency component from the target and added to the detector (8f ) Appears in the output. Therefore, in the output of the fourth comparator (7d), the internal noise of the receiver, the external interference signal component and the uncorrelated transmission signal component are subtracted, and only the target signal component appears, and the detection signal J can get.

Next, FIG. 4 is a diagram showing the details of the trigger pulse generator (24), in which (28) is an OR circuit and (29) is a pulse generator. When a detection signal is obtained by any one or more of the first to fourth comparators (9a) to (9d), the OR circuit (28) activates the pulse generator (29) and triggers with a constant pulse width. Generate a pulse K.

Next, FIG. 5 is a view of the cross section of the projectile orthogonal to the machine axis as seen from the rear of the projectile, where the y axis represents the left-right axis and the z axis represents the vertical axis. Quadrant I is defined by the positive direction of the y-axis, that is, the rightward direction and the positive direction of the z-axis, that is, the downward direction, and the quadrant I is defined below. Quadrants II, III, and IV are defined as shown in FIG. . In the figure, L represents the body of the flying body, and (4a) to (4d) represent the first to fourth antennas. FIG. 6 shows the above-mentioned first to fourth antennas (4a) to (4d).
Is a radiation pattern by P _A in the figure, P _A is a pattern for radiating a signal modulated by the first code by the first antenna (4a) to the lower part of the body of the flying body, and P _B
Is a pattern for radiating the signal modulated by the second code by the second antenna (4b) to above the body of the flying body, and P _C is received by the third antenna (4c) mounted on the left side of the body The pattern, P _D, is received by the fourth antenna (4d) mounted on the right side of the body, and P _E is transmitted downward by the first antenna (4a) and received by the right fourth antenna (4d). transmitting and receiving composite pattern, i.e., the beam I, P _F
Transmitting and receiving synthesized pattern transmitted by the first antenna downwards (4a), received in the left third antenna (4c), that is, the beam II, P _G is transmitted at the second antenna upward (4b) and, transmitting and receiving synthesized pattern received in the left third antenna (4c), i.e., the beam III, P _H is transmitted at the second antenna upward (4b), the right side of the fourth antenna (4d)
It shows the transmission / reception combined pattern received at, that is, beam IV.

By the way, since the output of the second detector (8b) is obtained by correlating the signal received by the third antenna (4c) on the left side with the first code, it corresponds to the output of beam II. The output of the detector (8c) of 3 corresponds to the output of beam III because the signal received by the third antenna (4c) on the left side is correlated with the second code. The output of the device (8e) is the first signal received by the fourth antenna (4d) on the right side.
Corresponding to the output of the beam I because it is obtained by correlating with the code of, the output of the sixth detector (8f) is the signal received by the fourth antenna (4d) on the right side with the second code. Since the correlation is taken, it corresponds to the beam IV.

FIG. 7 is a diagram showing details of the signal comparator (25).
B, C, E and F are second, third, fifth and sixth detectors (8b),
The outputs of (8c), (8e), and (8f) are (9e) to (9
j) are fifth to tenth comparators. Fifth comparator (9e)
In, the high-level comparison signal M is generated when the output C of the third detector (8c) is larger than the output B of the second detector (8b). In the sixth comparator (9f), compared with the output B of the second detector (8b), the fifth detector (8
When the output E of e) is larger, the comparison signal N of high level is generated. The seventh comparator (9g) generates a high-level comparison signal O when the output F of the sixth detector (8f) is larger than the output B of the second detector (8b). To do. A third detector (8c) in the eighth comparator (9h)
When the output E of the fifth detector (8e) is larger than the output C of the above, the high level comparison signal P is generated. The ninth comparator (9i) generates a high level comparison signal O when the output F of the sixth detector (8f) is larger than the output C of the third detector (8c). To do. Tenth comparator (9
In i), the high-level comparison signal R is generated when the output F of the sixth detector (8f) is larger than the output E of the fifth detector (8e). FIG. 8 is a diagram showing details of the quadrant determiner (26). In the figure, MR are outputs of the fifth to tenth comparators (9e) to (9j) shown in FIG. The comparison signal is shown and K in the figure is the pulse generator (29) shown in FIG.
Shows the trigger pulse which is the output of (30a) to (30f) is the first to sixth holders, (31a) to (31f) is the first to sixth inverters, (32a) to (32d). Are first to fourth AND circuits. When the trigger pulse K is input, the first to sixth cages (30a) to (30f) receive the input signals MR of the cages.
Is high level, a signal which holds the high level only for the time corresponding to the pulse width of the above-mentioned triva pulse K is generated. In addition, the first to sixth inverters (31a) to (31f)
Generates a low level output when each signal is at a high level, and generates a high level output when each input is at a low level. Then first
The fourth AND circuits (32a) to (32d) generate high-level determination signals S to V only when all of their three inputs are at high levels, and the respective first to fourth ignition circuits (10a). ) ~ (10d) is activated.

Here, for example, if a target exists in the quadrant I, the signal of the beam I is received more strongly than the signals of the beams II to IV. That is, the fifth of the outputs of the second, third, fifth and sixth detectors (8b), (8c), (8e) and (8f)
The output of the detector (8e) is the largest. Therefore, in the signal comparator (25), the outputs of the sixth and eighth comparators (9f) and (9h) become high level, and the tenth comparator (9j)
Output becomes low level. Of these three signals, the outputs of the sixth and eighth comparators (9f) and (9h) are input to the first AND circuit (32a) at the same level, and are output from the tenth comparator (9j). The output is inverted from the low level to the high level in the first inverter (31a) and the first AND circuit (3
2a), all three inputs of the first AND circuit (32a) become high level, and this output also becomes high level, so that the first ignition circuit (10a) operates. However, the output of the sixth comparator (9f) is inverted by the third inverter (31c) and becomes low level, so that the second A
The output of the ND circuit (32b) does not become high level and the second ignition circuit (10b) does not operate. Also, the 8th comparator (9h)
Since the output of is inverted by the fifth inverter (31e) and becomes low level and is input to the third AND circuit (32c), its output does not become high level and the third ignition circuit (10c) Does not work. Furthermore, since the output of the tenth comparator (9j) is input to the fourth AND circuit (32d) at low level, the fourth ignition circuit (10d) does not operate. That is, when the target exists in the I quadrant, only the first ignition circuit (10a) operates. Similarly, if there is a target in quadrant II, III or IV, the same applies to the second, third or fourth quadrant, respectively.
Only the ignition circuit (10b), (10c) or (10d) of the above will be activated, and the direction in which the target is present can be identified.

The second and fourth 1-bit delay circuits are the first and third bit delay circuits, respectively.
Although the output of the 1-bit delay circuit is delayed by 1 bit, the spread spectrum codes of the first and second code generators may be delayed by 2 bits.

Furthermore, in the above embodiment, the first to fourth antennas are arranged above, below, left, and right of the body of the flying body, but depending on how the quadrants are taken, they may rotate by 45 ° around the machine axis. , The first antenna at the lower right of the fuselage as seen from behind the body, the second antenna at the upper left, the third antenna at the lower left, the fourth
The antenna may be placed on the upper right.

The second code generator may use the code of the first code generator shifted by a half cycle.

〔The invention's effect〕

As described above, according to the present invention, since the transmission wave is spectrum-spread, the transmission power density per unit frequency band can be suppressed to a low level, so that it is difficult for the enemy side to detect it and even if it is disturbed. , By taking the correlation inside the close fuze, it is not affected by the interference on the adversary side who does not know the modulation code, and the effective target detection range of the close fuze is one bit behind the transmitted modulation code. The target detection range can be matched with the effective range of the warhead because it is kept within the round-trip distance of the radio wave, which corresponds to the phase of 1 bit before and after the target. There is an effect that it is possible to identify whether to do.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a proximity fuze according to an embodiment of the present invention, FIG. 2 is a diagram showing a relation between time and output voltages of a first bias adder and a second detector, and FIG. FIG. 4 is a diagram showing the configuration of a signal detector, FIG. 4 is a diagram showing the configuration of a trigger pulse generator, and FIG. 5 is a cross-sectional view of a flying object.
A diagram showing the definition of the IV quadrant and showing the mounting positions of the first to fourth antennas, FIG. 6 is a diagram showing transmission patterns, reception patterns, and transmission / reception combination patterns by the first to fourth antennas, and FIG. 7 is FIG. 8 is a diagram showing the configuration of a signal comparator, FIG. 8 is a diagram showing the configuration of a quadrant determiner, and FIG. 9 is a diagram showing the configuration of a conventional proximity fuze. In the figure, (1) is an oscillator, (2) is a directional coupler,
(4) is an antenna, (5) is a mixer, (6) is a video amplifier, (7) is a Doppler filter, (8) is a detector,
(9) is a comparator, (10) is an ignition circuit, (12) is a modulator,
(14) is a distributor, (15) is a correlator, (16) is a bias adder, (19) is a code generator, (20) is a 1-bit delay circuit, (22) is a clock oscillator, and (23) is Signal detector,
(24) is the trigger pulse generator, (25) is the signal comparator,
(26) is a quadrant determiner, (28) is an OR circuit, (29) is a pulse generator, (30) is a retainer, (31) is an inverter, and (32) is AN.
It is a D circuit. In the drawings, the same or corresponding parts are designated by the same reference numerals.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keiki Hidaka 345 Kamimachiya, Kamakura City, Kanagawa Mitsubishi Precision Co., Ltd. Kamakura Factory (56) Reference JP-A-1-143990 (JP, A) JP Flat 1-136086 (JP, A)

Claims (1)

[Claims] 1. A clock oscillator, a first code generator driven by the output of the clock oscillator to generate a spread spectrum code, and a signal generated by delaying the output of the first code generator by one bit. One 1-bit delay circuit, a second 1-bit delay circuit that is generated by further delaying the output of the first 1-bit delay circuit by 1 bit, an oscillator that generates a transmission signal, and an output of the oscillator. A directional coupler that divides the part, a first divider that divides the output of the directional coupler into two, and one output of the first divider with the output of the first 1-bit delay circuit. A first modulator that performs spread modulation, and a first antenna that is attached to the lower part of the fuselage body for transmitting the output of the first modulator in a target direction,
A second spread spectrum code generated by the output of the clock oscillator, the spread spectrum code being different from that of the first code generator;
Code generator, a third 1-bit delay circuit for delaying the output of the second code generator by 1 bit, and an output of the third 1-bit delay circuit by further delaying it by 1 bit. Of the fourth 1-bit delay circuit, the second modulator for spreading-modulating the other output of the first distributor with the output of the third 1-bit delay circuit, and the second modulator. A second antenna attached to the upper part of the body of the flying body for transmitting output to the target direction, and a flying body for receiving radio waves transmitted in the target direction by the first and second antennas and reflected by the target A third antenna mounted on the left side of the body of the body, a second distributor for dividing a part of the output of the oscillator branched by the directional coupler into two, an output of the third antenna and the third antenna. A first mixer that mixes with the output of one of the two distributors A mixer, a first video amplifier for amplifying the output of the first mixer, and a first correlator for correlating the output of the first video amplifier with the output of the first code generator, A second correlator for correlating the output of the first video amplifier with the output of the second 1-bit delay circuit, the output of the first video amplifier and the fourth 1
A third correlator that correlates with the output of the bit delay circuit,
A fourth antenna mounted on the right side of the body of the flying body that receives radio waves transmitted from the first and second antennas in the target direction and reflected by the target, and the output of the fourth antenna and the fourth antenna. A second mixer for mixing the other output of the second distributor, a second video amplifier for amplifying the output of the second mixer, an output of the second video amplifier and the second code A fourth correlator for correlating with the output of the generator, a fifth correlator for correlating the output of the second video amplifier with the output of the second 1-bit delay circuit, and the second correlator. The sixth correlator for correlating the output of the video amplifier with the output of the fourth one-bit delay circuit and the outputs of the first to sixth correlators are input through the first to sixth Doppler filters, respectively. First to sixth wave detectors, and the above first wave detector A first bias adder for adding a constant bias voltage to the output, a second bias adder for adding a constant bias voltage to the output of the fourth detector, and an output of the first bias adder And the outputs of the second and third detectors are compared, and the detection signals are generated when the outputs of the second and third detectors are larger than the output of the first bias adder. The outputs of the first and second comparators and the second bias adder are compared with the outputs of the fifth and sixth detectors, and the fifth and sixth outputs are output more than the outputs of the second bias adder. A signal detector comprising third and fourth comparators which respectively generate detection signals when the output of the detector 6 is large, and one or more of the first to fourth comparators of the signal detectors. Generates a trigger pulse when a detection signal is obtained from Riga pulse generator, a signal comparator including fifth to tenth comparators for comparing two outputs of the outputs of the second, third, fifth and sixth detectors, and the signal comparator The quadrant discriminator that determines the quadrant in which the target exists based on the comparison result of 1) and the first to 1st that operate when the quadrant discriminator determines that the target exists in the quadrant I, II, III, or IV, respectively. A proximity fuze comprising a fourth ignition circuit.