Light wave homing instruction
A light wave homing instruction (I say homing in this way how about) is a homing instruction through the medium of the light wave.
I detect a light wave to come back from an aim with a seeker and am a method to catch a sign by steering a ship in the direction. In the steerage, most adopt a proportional navigation (PN) or a reinforcement proportional navigation (APN).
In an electromagnetic wave, the light wave continues being able to apply it in a small device more in comparison with an electric wave (microwave in particular), and permeability in the atmosphere is low, and there is the fault that the distance that therefore can detect an aim has a shorter from the characteristic top as the frequency. From this, the weapon of the light wave homing instruction method tends to be managed as a handier thing at the range that is shorter than an electric wave homing instruction.
Table of contents
Passive method
Infrared homing
I catch infrared rays (InfraRed, IR) which an aim rises from by an infrared sensor, and the infrared homing (English: Infrared homing, IRH) instruction is an instruction method to guide a missile to the direction.
I possessed ability to get fire and four because an instruction process after the discharge concluded in a missile and because guidance controls were relatively small size, light weight, the downsizing of the missile was possible and because an instruction process was simple, the radar of the mother ship was poor and did not have any problem either. It is done important business with an interceptor missile having the engine that an aim becomes the big heat source. In addition, with the change of the detective wavelength and the progress of the instruction system, the adoption example to an anti-ship missile and an anti-tank missile begins to appear, too.
The infrared rays have lower permeability within the range of the atmosphere than an electric wave in a characteristic of the frequency. From this, in the old Western countries, I often adopt IRH instruction to the missile of the range in the visibility by a radar instruction in AAM of the range out of the visibility. On the other hand, I may adopt IRH instruction in AAM of the visibility outside range because I take the tactics to fire the missile of two kinds of two of a radar instruction and the infrared rays instruction at the same time to make the evasion of the target difficult, and to improve hit probability in the former east side countries.
I developed an infrared instruction-type ケ bomb in Japan for last years of the Pacific War, but greeted the end of the war before being completed.
Characteristic of the aim
Because there is a law (Wien's displacement law) that the wavelength of the peak of the radiation from a black body is inversely proportional to temperature, the infrared frequency emitted by the temperature of the aim is prescribed.
- Vehicle, war vessel
- I am comprised of the body / hull which is high in around several degrees and the slightly high temperature engine part, and there is emission to assume about 10µm a peak. A radiant intensity greatly changes by an aspect corner and strongly receives influence of the curvature of the earth in the capture at the long distance in particular.
- The background consists of the surface of the earth, the sea surface, and contrast is relatively small, and the influence of the clutter is big.
- Plane, cruise missile
- In the plane, emission by the exhaust from a high temperature jet engine is it in emission by the aerodynamic heating (because a body hits the air, I thermally insulate it and am compressed) in the whole body mainly on a leading edge again in many cases in the rear of the body.
- A thing by the exhaust: In the jet exhaust (プルーム) that 3 micrometers (µm) of degree of the vent of the body rear is exhausted backward for a peak, infrared rays to 5µm degree are emitted mainly on heated carbon dioxide gas.
- A thing by the aerodynamic heating: I am almost equivalent to 10µm obi (wavelength 8 - 12µm).
- The background is constructed by the sky and cloud, the horizon / horizon, and there is relatively big contrast.
- Ballistic missile
- Because the re-entry body becomes the pole super sonic speed (if even IRBM is around 2km per second, ICBM around 7km per second) at the time of re-entry into the earth's atmosphere, it is heated up than several thousand degrees by aerodynamic heating and there is much emission of the short wavelength and starts it.
Characteristic every generation
The IRH instruction system developed with a technological change as follows.
- The first generation
- The earliest IRH instruction system adopted the infrared sensor of the non-cooling type with the lead sulfide (PbS) fret electric element. The detective wavelength is 近, short wavelength red outside (N/SWIR) band of about 1-3 micrometers (µm), and this is almost equivalent to the infrared emission band of the jet vent. Therefore, as for the first generation IRH instruction system, it was able to catch an aim only from the backward quadrant that the view could catch jet vent itself at the time of air-to-air shooting, too. In addition, capture has been canceled relatively easily when the capture was very unstable, and an aim performed movement.
- Therefore, measures to cool a sensor came to be introduced to reduce a thermal noise from the about 1960s, and to improve sensitivity. There is a thing using a heat electric effect that the cooling system used Joule = Thompson effect, but the former is slightly major.
- The second generation
- Conventionally, with the infrared sensor of the guidance controls (seeker) of the missile, I adopted a lead sulfide (PbS) fret electric element as a light receiving element, but, in the 1970s, the quantum type (cooling type) infrared rays sensor which assumed indium antimonide (InSb) photodiode a light receiving element reached it for a practical use stage. These infrared rays sensor was able to detect the middle wavelength red outside (MWIR) band where had a long wavelength than a thing by PbS.
- Not vent itself, the detection of プルーム exhausted from here was in this way enabled. Although the detection to プルーム has a big aspect dependence; of the body could catch it for all laps and was almost expected when could realize ability for all direction war (All-Aspect Capability, ALASCA). In addition, there was the defendability improvement (the reinforcement of the IRCCM ability) effect to an infrared jamming technology, and the reliability of the circuit improved the semiconductor which did it including adoption of the photodiode by making it it, too.
- In addition, at the end of 1980s, the system which used ultraviolet rays sensor by gallium arsenide (GaAs), gallium nitride (GaN) and the cadmium sulfide (CdS) together came up. I aimed at reinforcing IRCCM ability more by using the detection of emitted ultraviolet rays together, and these are named two long light wave homing (IR/UVH) instruction systems (two colors of seekers) by the shell of the plane.
- The third generation
- An infrared image (Imaging InfraRed, IIR) instruction system has begun to appear by becoming it an integrated circuit and the many elements of the infrared sensor by the technological change of the microprocessor from the 1990s. By the introduction of the image recognition technology, the IRCCM ability improved drastically, and the instruction precision improved again, too.
- At this time, the ability for off boresight shooting came to be made much of, too. I enabled this by realization of aim or (LOAL) which caught an aim after discharge by the introduction of expansion and the middle instruction of the missile seeker detection angle by attacking it with the off boresight for the inimical character plane which existed at the position that greatly missed the front. I equip the body side with Head Mount Display (HMD) to show ability for off boresight shooting enough, and a change of the avionics is necessary.
- In addition, I receive the practical use of the non-cooling type (temperature graph) image sensor of 常温作働 and practical use of the element material which can cope with an aim of the normal temperature including cadmium mercury (HgCdTe) telluride (can detect the infrared rays of the 10µm Zone), and the application to the field of open battle progresses, too and is adopted to the third generation anti-tank missile. Because I comprise ability to get fire and four by the IRH instruction method including IIR (according to the statement above) whereas instruction work was necessary for a conventional anti-tank missile after the discharge in the mainstream command guidance, movement but to evade counterfire just after discharge is enabled, and the viability of the missile archer greatly improves. But, as for picture, the latter is generally superior when I compare the cooling type with the non-cooling type [1].
Image instruction
The image (English: electro-optical, TV) instruction is an instruction method to perform an end instruction in a video camera carried on the missile tip.
The image instruction,
- Hit precision is high with CEP3 - 6m
- I am usable in movement target unlike GPS
- The mother ship can leave the spot after discharge unlike laser guidance
- I can use it in two scenes of the anti-warship, from the air
- Because I can confirm the moment of the hit with an image, I can omit trouble of the military gains confirmation
- I am stronger in jamming than a radar instruction
I have などの good point. On the other hand,
- Rock requires trouble unlike GPS and is not suitable for a large number of simultaneous discharge
- It is more expensive than GPS, laser guidance
- It is of narrow outlook on life, and precision is found for an instruction middle than a radar type
- It is hard to use you as a super sonic speed missile
I have などの bad point.
In addition, not only it is said that I let merely aim hit it by the image recognition instruction, but also there is a merit that the designation of the impacted bomb position can be enabled in which which is infrared visible light. I mean that I can neutralize it effectively by this striking the helm rooms of the hostile craft when, for example, I use it for an anti-warship attack, and blowing up any place of the bridge in the air bombardment of enemy forces attack.
Although a sensor was a visible light image method, as for the early model such as the AGM-62 wall eye, a hand-operated order was necessary for an instruction. If a human being ordered the aim image in the image once, a computer performed image recognition and locked it, and a computer distinguished an aim and a background automatically afterward, and an aim was improved afterwards to an image recognition instruction to pursuit autonomy. I became able to in this way leave the mother ship after discharge immediately. In addition, it was necessary that a mother ship closed the aim before discharge at first and worked on a lock-on, but came to be able to lock it afterwards without a mother ship approaching the aim. In this case I approach the aim by a middle instruction by GPS and the INS and start an optical sensor near an aim, and the missile which shot transmits an image to a by radio backward mother ship without locking it, and a lock-on will work by remote control. SLAM is the earliest thing in the west, but, for the model which adopted this kind of method, aim capture by the remote control is enabled even if a discharge mother's body and the distance with the missile are far more than 1,000km by using satellite data link in the タクティカル Tomahawk put to practical use afterwards as a transmission course of the image information.
Cicada active method
Cicada active laser homing
The cicada active laser homing (English: Semi-Active Laser Homing, SALH) irradiates it with a laser beam for an aim from the laser target designating system of the discharge mother's body (or an other irradiation machine) and is a method to guide a missile to the direction by catching the glance from an aim with the seeker of the missile.
The laser guidance method was relatively classic for the instruction method of the missile, but, in the early days, there were many things that the beam riding methods (LOSBR) such as semiautomatic order line of sight agreement instruction methods (SACLOS) that were a kind of the command guidance were adopted. However, instruction errors increased with a range getting longer and, in this case, principle called the command guidance, had a problem in shooting precision for the movement target in particular. In contrast, because the SALH method is a homing instruction by a proportional navigation (PN) to the reinforcement proportional navigation (APN), there is the good point that instruction precision improves as much as a missile approaches a sign, but, on the other hand, it is technically higher, and there is the fault becoming expensive because I perform the operation for steerage on the missile side.
In addition, like LOSBR method, the irradiation machine has to continue irradiating the laser until a laser guided weapon hits it in the SALH method. This is a problem to perform of 通底 with the cicada active radar homing (SARH) method in the electric wave homing instruction. From this, and, separately from a discharge mother's body, I put a laser irradiation machine on an unmanned plane to improve survival characteristics of the discharge mother's body or may deploy it in the ground Special Forces.
When view is bad, I am not suitable under the bad weather such as an aim and dense fog and the heavy rain to move at high speed until it hits it because you must continue always irradiating it in pinpoint.
Countermeasure
Neutralization is possibility by a flight guard () of the commercial airplane missile defense system () and light wave interference technology such as Northrop Grumman Guardian () in the Directional Infrared Counter Measures () and commercial airplane use as part of a flare and AN/ALQ-144 () and general-purpose infrared jamming plan () for a passive expression, cicada active expressions.
References
- ^ "state-of-the-art of the MEMS material." Masaki Esashi, CMC Publishing Co.,Ltd, 2007. August 30, 2010 reading.
- Association of defense technology journal editorial department "Chapter 6 deployment electronic equipment technology" "all of weapon and defense technology series 1 plane technologies" defense technology, 2005. ISBN 978-4,990,029,821。
- For association of defense technology journal editorial department "Chapter 2 light wave homing instruction" "all of weapon and defense technology series 3 missile technologies" defense technology, 2,006 years, it is 23-55 pages. ISBN 978-4,990,029,821。
This article is taken from the Japanese Wikipedia Light wave homing instruction
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