JPH0412399Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a proximity fuze using an infrared ranging method.

(Prior Art) Conventional optical fuzes include those using a target detection method, a distance measurement method, or a proximity method. Each of these has the following drawbacks.

(b) Target detection method: The target detection method is a method for detecting targets such as missiles or jet aircraft that emit a large amount of heat or infrared light from their own power source; The disadvantages include that it can only be applied to targets that emit heat, and that the towing distance varies depending on the amount of heat radiated by non-target objects.

(b) Distance measurement method: The distance measurement method emits a light pulse from a fuze, receives the reflected light that is reflected from the target object, and measures the time difference between the emitted light pulse and the received reflected light. This is a so-called pulse radar method that converts distance from this time difference. Although this method can improve distance measurement accuracy,
In order to obtain a distance measurement accuracy of 1 m, it is necessary to identify pulse signals in units of approximately 3 nsec, which has the drawback that the response speed of the signal processing circuit must be extremely high.

(c) Proximity method: In the proximity method, light (pulsed or CW) is emitted from a fuze, the reflected light from the target is received, and the difference in intensity between the emitted light and the received light is detected. Alternatively, it is an active method that detects the Doppler frequency. This method uses the difference in intensity between the emitted light and the received light, and the difference in intensity differs depending on the effective reflection area and reflection angle of the target, while the method using Doppler frequency determines whether the target is a moving object or a stationary object. Even if the fuze and target are at the same distance, the Doppler frequency will have different values due to changes in the object or the fuze flight speed. Therefore, if it is due to the difference in the intensity of the emitted light and the received light, the effective reflective area of the target,
Reflection angle In addition, when using Doppler frequency, detection conditions cannot be determined uniformly when considering conditions such as whether the target is a moving object or a stationary object and changes in the flight speed of the fuze. The disadvantage is that it can only be used within certain limits.

(Problems that the invention aims to solve) As mentioned above, fuzes using several methods have been proposed, but each method produces errors or attempts to improve accuracy. This requires a high-speed response, and also poses problems such as complicated condition settings.

(Means for Solving the Problems) The present invention that solves the above drawbacks will be explained in detail using figures. FIG. 1 shows an embodiment of the signal system of the present invention, and first only the signals of each part will be described, and the functions and operations will be explained together with FIGS. 2 and 3. In the figure, 1 is a projection lens, 2 is a light emitter, 3 is a light emitter drive circuit, 4 is a light emission signal circuit, and 5
is a synchronization circuit, 6 is a clock circuit, 7 is a signal generator, 8 is a light receiving lens, 9 is an infrared passing filter, 10 is a multi-division infrared detector, 11 is an analog switch circuit, 12 is a timing circuit, 13 is an amplifier circuit , 14 is a sample hold circuit, 15 is an analog-to-digital conversion circuit, 16 is an arithmetic circuit,
17 is a distance setting section, 18 is an ignition circuit, 19 is an explosive section, and 20 is a power supply circuit that supplies power to necessary parts of each of the above components.

FIGS. 2A and 2B are diagrams for explaining the optical system of the present invention. Infrared light L1 emitted from a light emitter 2 using an infrared diode, an infrared laser diode, etc. is projected through a projection lens ₁ onto a target object X such as a moving object, a stationary object, an object on the sea surface, or an object on the ground surface. Next, the reflected light from target X
The reflected light L ₂ that has passed through the light receiving lens 8 and the infrared passing filter 9 is detected by the multi-segment infrared detector 10 which is arranged a predetermined distance (baseline length l) from the light emitter ₂ . The focal position of the reflected light _L2 at the multi-segment infrared detector 10 differs depending on the lens system and the position on the base line. The in-focus position can be detected by comparing the output between each divided element of the multi-divided infrared detector 10. As shown in Figure 2 B,
It is assumed that the in-focus position is D. This is a distance detector based on the triangulation method, and the multi-divided infrared detector 10 is divided into 3 to 10 zones for zone focus, 100
If the number of divisions is greater than that, alpha focus will occur, and the detection distance accuracy will vary depending on the number of divisions.

Next, in FIG. 3, the symbols a to j shown in the diagram of FIG.
FIG. 3 is a timing chart showing signals at positions indicated by . In this timing chart, the portion indicated by a broken line in the middle is a repeated portion. Third
The operation of the embodiment shown in FIG. 1 will be explained with reference to the drawings.

A signal generator 7 generates a signal a, and a clock circuit 6 obtains a clock signal. A light emitting signal e is obtained by the light emitting signal circuit 4 from the signal c of the synchronizing circuit 5 and the clock signal b, and the light emitting signal e is used to generate the signal a of the signal generating circuit 7 in the light emitter drive circuit 3.
A light emission signal f is obtained. The light emitter 2 emits light in response to a pulse-modulated light emission signal f, and infrared light _L1 is projected onto the target object X through the projection lens 1. Reflected light L ₂ from target object X is received by light receiving lens 8
The light passes through an infrared passing filter 9 and reaches a multi-segment infrared detector 10. The n detection outputs detected by the n-divided infrared detector 10 are sequentially extracted as signals g by the sequential pulses of the analog switch circuit 11 and timing circuit 12, and the signal g is sent to the amplifier circuit. 13. The output signal of the amplifier circuit 13 is sampled by a sample hold circuit 14 as shown by a signal h, and is converted into an analog-to-digital conversion circuit (A/D converter) 1.
Enter 5. Analog-digital conversion circuit 1
5 converts an analog quantity into a digital quantity, and its A/D output signal i is shown in 4-bit BCD (binary coded decimal). The number of bits here is related to distance accuracy, so the number of bits will be determined as necessary.
This digital amount is calculated by the arithmetic circuit 16, which compares the sizes of the front and rear outputs of the n outputs of the multi-segment infrared detector 10 within one frame pulse, and sets the distance setting unit 1.
7, and if they have the same pulse sign, a firing signal is input to the firing circuit 18. Firing circuit 18
In response to this ignition signal, the detonator 19 detonates and sends a sufficient amount of electricity to the detonator to cause an explosion.

(Effects of the invention) The effects of the invention are less susceptible to disturbance light including ECM. Conventional methods, whether active or passive, detect reflected light based on quantitative and temporal standards, so they are susceptible to interference regardless of whether it is CW, AM, or FM. By using the comparison between adjacent multi-divided infrared detectors as a reference, and by using timing pulses and carrier pulses, it is possible to reduce the influence of interference light and external disturbance light.

For example, the strength of disturbance light (difference between night and day, interfering light)
Even if this happens, the overall output level of the multi-segmented infrared detector only changes, and it does not lead to a level difference within the splits. In addition, in order to create a level difference with interfering light, infrared light in the passband of an infrared passing filter is focused on a multi-segment infrared detector, and the modulation frequency is the same as that of the carrier pulse. Must-have. Even if you create a level difference with this, it will not cause interference unless the focus point is at the altitude set in the settings section.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the signal system of the invention, Fig. 2 is a diagram showing an embodiment of the optical system of the invention, and Fig. 3 is a time chart for explaining the operation of the invention. be. DESCRIPTION OF SYMBOLS 1...Projection lens, 2...Light emitter, 3...Light emitter drive circuit, 4...Light emission signal circuit, 5...Synchronization circuit, 6...Clock circuit, 7...Signal generator, 8
...Receiving lens, 9...Infrared passing filter,
10...Multi-divided infrared detector, 11...Analog switch circuit, 12...Timing circuit, 13
...Amplification circuit, 14...Sample and hold circuit,
15...Analog-digital conversion circuit, 16...
... Arithmetic circuit, 17 ... Distance setting section, 18 ... Ignition circuit, 19 ... Explosion section, 20 ... Power supply circuit, X ...
...Target, L ₁ ... Infrared light, L ₂ ... Reflected light.

Claims (1)

[Claims for Utility Model Registration] (1) A light emitting section consisting of a projection lens and a light emitter, a light receiving lens and a light receiving section consisting of a multi-segmented infrared detector are arranged at a predetermined optical axis angle and at a predetermined interval, and the multi-segmented infrared An infrared distance measuring proximity fuze, characterized in that a firing operation is performed when it is detected that a target object, the light emitting section, and the light receiving section have reached a predetermined positional relationship based on a focused state of a detector. (2) The clock signal of the clock circuit and the synchronization signal of the synchronous circuit are input to the light emission signal circuit, and the output signal of the light emission signal circuit pulse-modulates the signal of the signal generator in the light emitter drive circuit. a signal system and an optical system that drive a light emitter with a light emission signal and project infrared light emitted by the light emitter onto a target through a projection lens;
The reflected light from the target object is received by a light receiving lens, and detected by a multi-segmented infrared detector divided into 3 or more n pieces (n is an integer) separated from the light emitter by a predetermined distance via an infrared passing filter. , the detection signal and the timing signal of the timing circuit are obtained through an analog switch circuit, which is amplified by an amplifier circuit, then sampled by a sample hold circuit, and the sampled signal is converted into an analog signal.
By converting the digital signal into a digital signal by a digital conversion circuit, processing the digital signal and the distance setting part signal in an arithmetic circuit, and sending the ignition signal to the ignition circuit when the digital signal and the distance setting part signal match, An infrared distance measuring proximity fuse according to claim 1, which comprises an optical system and a signal system for detonating a detonating part.