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37-426: Early infrared homing missiles had two limitations that made them difficult to use in combat situations. The first was that the seeker was relatively insensitive and required large, hot sources to reliably track a target. In practice, this meant the engine of the enemy aircraft had to remain visible to the missile through the shot. The other was that the seeker had a limited field of view (FOV), meaning it could only see

74-468: A 5.8 degree (angular) field of view might be advertised as having a (linear) field of view of 102 mm per meter. As long as the FOV is less than about 10 degrees or so, the following approximation formulas allow one to convert between linear and angular field of view. Let A {\displaystyle A} be the angular field of view in degrees. Let M {\displaystyle M} be

111-776: A European-led effort to develop ASRAAM . However, the Soviet Union did develop such a missile and fielded the Vympel R-73 by 1985, taking the lead in short-range missile technology and performance for the first time since the Sidewinder entered service. This caused a number of countries to develop short-range missile programs to counter it, such as Python-4 in Israel , ASRAAM in Britain , MBDA MICA in France , AIM-9X in

148-494: A detector element (a pixel sensor) is sensitive to electromagnetic radiation at any one time, is called instantaneous field of view or IFOV. A measure of the spatial resolution of a remote sensing imaging system, it is often expressed as dimensions of visible ground area, for some known sensor altitude . Single pixel IFOV is closely related to concept of resolved pixel size , ground resolved distance , ground sample distance and modulation transfer function . In astronomy ,

185-614: A high off-boresight lock-on capability capable of being targeted by a Helmet Mounted Sight (HMS), allowing it to be fired at targets which were not directly ahead, making it far easier to achieve a firing position. The solid-propellant rocket used thrust vectoring for control giving it superior turning capability over the Sidewinder. At the time the navy was developing VFX, the Air Force was developing its F-X concept , which emerged with an almost identical set of requirements as VFX. And as part of that project, they also concluded they needed

222-720: A much better missile, and began the AIM-82 to that requirement. Since both missiles were more or less identical in their role, it was decided to abandon the AIM-82 in favour of the Agile. The AIM-95A was developed to a point where flight tests were carried out including test firing at China Lake and inclusion in the ACEVAL/AIMVAL Joint Test & Evaluation conducted with both the F-14 and F-15 at Nellis AFB in 1975–78. As

259-581: A much smaller, shorter-range weapon was the correct solution, a "gun that fires around corners". This led to the Taildog concept, which became SRAAM , which was ultimately canceled in favor of Skyflash . The Soviet Union also began development of an advanced high off-boresight SRM with thrust vectoring and subsequently fielded the R-73 /AA-11 Archer on the MiG-29 in 1985. NATO learned about their performance due to

296-626: A result of escalating costs, the project was canceled in 1975. Instead, an improved version of the Sidewinder was developed for use by both the Air Force and Navy. Although this was intended to be an interim solution, in fact, the AIM-9 continues in service today. While the AIM-95 program was being carried out, the Royal Air Force had come to similar conclusions about the need for a new high-maneuverability missile. However, their studies suggested

333-471: A target at longer ranges. The new design would address both of these problems; a new seeker would allow lock-on from any angle including the front of the aircraft, greatly improved manoeuvrability would allow it to attack targets even at rapid crossing speeds, and a larger and more powerful motor would give it equal or greater range under all conditions. The resulting Agile design was equipped with an infrared seeker for fire and forget operation. The seeker had

370-401: Is further relevant in photography . In the context of human and primate vision, the term "field of view" is typically only used in the sense of a restriction to what is visible by external apparatus, like when wearing spectacles or virtual reality goggles. Note that eye movements are allowed in the definition but do not change the field of view when understood this way. If the analogy of

407-443: Is much more sensitive at night relative to foveal vision (sensitivity is highest at around 20 deg eccentricity). Many optical instruments, particularly binoculars or spotting scopes, are advertised with their field of view specified in one of two ways: angular field of view, and linear field of view. Angular field of view is typically specified in degrees, while linear field of view is a ratio of lengths. For example, binoculars with

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444-452: Is slightly larger, as you can try for yourself by wiggling a finger on the side), while some birds have a complete or nearly complete 360-degree visual field. The vertical range of the visual field in humans is around 150 degrees. The range of visual abilities is not uniform across the visual field, and by implication the FoV, and varies between species . For example, binocular vision , which

481-453: Is the focal length , here the sensor size and f {\displaystyle f} are in the same unit of length, FOV is in radians. In microscopy, the field of view in high power (usually a 400-fold magnification when referenced in scientific papers) is called a high-power field , and is used as a reference point for various classification schemes. For an objective with magnification m {\displaystyle m} ,

518-423: Is the basis for stereopsis and is important for depth perception , covers 114 degrees (horizontally) of the visual field in humans; the remaining peripheral ~50 degrees on each side have no binocular vision (because only one eye can see those parts of the visual field). Some birds have a scant 10 to 20 degrees of binocular vision. Similarly, color vision and the ability to perceive shape and motion vary across

555-604: The AIM-7 Sparrow . The high-tech jets could easily fire a Sparrow against the F-5 but, because of the requirement to maintain the lock from launch till impact, the cheaper fighter could fire an all-aspect heat-seeker missile before it was shot down by the Sparrow. And because the heat seeker was fire-and-forget , in reality the expensive, high-tech jet was taken out by a much cheaper F-5. However, this situation occurred because

592-692: The AIM-9L Sidewinder . AIMVAL findings were that the new missiles were no better than the AIM-9L, resulting in termination of the Navy AIM-95 Agile off-boresight/ thrust vectoring air-to-air missile program, which was under development at the time. Actual seeker hardware was utilized in AIMVAL. ACEVAL/AIMVAL resulted in development of AMRAAM, but did not recommend development of a high off-boresight short-range missile, opting instead for

629-734: The Air Intercept Missile Evaluation (AIMVAL) were two back-to-back Joint Test & Evaluations chartered by the United States Department of Defense that ran from 1974-78 at Nellis Air Force Base in Nevada . Both the U.S. Air Force and U.S. Navy participated, contributing a team of F-15 Eagle and F-14 Tomcat fighter aircraft and using the local F-5E Aggressor aircraft as the Red Force . The fundamental question that needed to be answered

666-719: The UK Schmidt Telescope had a field of view of 30 sq. degrees. The 1.8 m (71 in) Pan-STARRS telescope, with the most advanced digital camera to date has a field of view of 7 sq. degrees. In the near infra-red WFCAM on UKIRT has a field of view of 0.2 sq. degrees and the VISTA telescope has a field of view of 0.6 sq. degrees. Until recently digital cameras could only cover a small field of view compared to photographic plates , although they beat photographic plates in quantum efficiency , linearity and dynamic range, as well as being much easier to process. In photography,

703-588: The United States , and IRIS-T in Germany . It was claimed that the Soviet Union benefited more from ACEVAL/AIMVAL than did its Western counterparts. Additionally, part of the evaluation was to determine if the technology of the day had progressed to such a point that situational awareness was no longer a factor in air-to-air combat. The natural expectation in the beyond-visual-range missile trials

740-516: The F-15's and F-14's larger and longer range radars could not be used to their full advantage due to the engagement rule that a pilot must visually identify its target before firing a missile. ACEVAL as such set the requirement for an true active homing, fire-and-forget missile, which became the AIM-120 AMRAAM series. AIMVAL examined five missile concepts under consideration as replacements for

777-487: The FOV is related to the Field Number (FN) by if other magnifying lenses are used in the system (in addition to the objective), the total m {\displaystyle m} for the projection is used. The field of view in video games refers to the field of view of the camera looking at the game world, which is dependent on the scaling method used. ACEVAL The Air Combat Evaluation (ACEVAL) and

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814-574: The German reunification and efforts began to match or exceed the R-73's performance with the IRIS-T , AIM-9 X and MICA IR programs. Field of view The field of view ( FOV ) is the angular extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors, it is a solid angle through which a detector is sensitive to electromagnetic radiation . It

851-461: The eye's retina working as a sensor is drawn upon, the corresponding concept in human (and much of animal vision) is the visual field . It is defined as "the number of degrees of visual angle during stable fixation of the eyes". Note that eye movements are excluded in the visual field's definition. Humans have a slightly over 210-degree forward-facing horizontal arc of their visual field (i.e. without eye movements), (with eye movements included it

888-465: The field of view is that part of the world that is visible through the camera at a particular position and orientation in space; objects outside the FOV when the picture is taken are not recorded in the photograph. It is most often expressed as the angular size of the view cone, as an angle of view . For a normal lens focused at infinity, the diagonal (or horizontal or vertical) field of view can be calculated as: where f {\displaystyle f}

925-799: The field of view is usually expressed as an angular area viewed by the instrument, in square degrees , or for higher magnification instruments, in square arc-minutes . For reference the Wide Field Channel on the Advanced Camera for Surveys on the Hubble Space Telescope has a field of view of 10 sq. arc-minutes, and the High Resolution Channel of the same instrument has a field of view of 0.15 sq. arc-minutes. Ground-based survey telescopes have much wider fields of view. The photographic plates used by

962-408: The image resolution (one determining factor in accuracy). Working distance is the distance between the back of the lens and the target object. In tomography , the field of view is the area of each tomogram. In for example computed tomography , a volume of voxels can be created from such tomograms by merging multiple slices along the scan range. In remote sensing , the solid angle through which

999-638: The late 1960s the Navy began development of the Grumman F-14 Tomcat fighter, which offered dramatically improved performance over their F-4 Phantoms . The Tomcat's origins begin in the Fleet Air Defense (FAD) concept that was based on aircraft carrying very long-range missiles and radars, allowing them to attack enemy aircraft at ranges on the order of 100 miles (160 km). While the FAD

1036-528: The launch aircraft would be both behind the target and flying in the same general direction. This would maximize the chance that the target would still be visible to the missile after it was launched. Unfortunately, such manoeuvring was both time consuming and potentially difficult to arrange, and in combat, there were many situations where a target would cross in front of the fighter in a "snap shot". To provide some capability in these situations, autocannons were hastily added to those fighters that lacked them. In

1073-407: The linear field of view in millimeters per meter. Then, using the small-angle approximation : In machine vision the lens focal length and image sensor size sets up the fixed relationship between the field of view and the working distance. Field of view is the area of the inspection captured on the camera’s imager. The size of the field of view and the size of the camera’s imager directly affect

1110-449: The more expensive F-14's. The results had other impacts as well, such as decisions regarding missile development. ACEVAL looked at the effectiveness of the tactics utilized by high-performance U. S. aircraft against simpler, threat-type aircraft equipped with all-aspect missiles. The conclusion was that a cheaper fighter such as an F-5 could engage the more expensive jets like F-14 or F-15 that carried big radar and SARH missiles such as

1147-404: The retina, together with a larger representation in the visual cortex – in comparison to the higher concentration of color-insensitive rod cells and motion-sensitive magnocellular retinal ganglion cells in the visual periphery, and smaller cortical representation. Since rod cells require considerably less light to be activated, the result of this distribution is further that peripheral vision

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1184-501: The same direction. In these situations, the seeker might see the target's engine and send the growling signal that indicated lock-on , but would fail to track when fired because the target would move out of the FOV in the time while the missile was flying off the mounting rail. Faced with these dismal results, the US Navy and then US Air Force introduced new training syllabuses that placed much more emphasis on pre-shot manoeuvring, so

1221-567: The target if it was in front of the missile. These limitations were made clear during the Vietnam War , when early missiles like the AIM-4 Falcon and AIM-9 Sidewinder had success rates on the order of 9 and 14%, respectively. Much of this was due to the fact that pilots had been trained to approach using radar or ground-controlled interception , which placed the enemy aircraft somewhere in front of them, but not necessarily flying in

1258-417: The visual field; in humans color vision and form perception are concentrated in the center of the visual field, while motion perception is only slightly reduced in the periphery and thus has a relative advantage there. The physiological basis for that is the much higher concentration of color-sensitive cone cells and color-sensitive parvocellular retinal ganglion cells in the fovea – the central region of

1295-497: Was also clear. Given the dismal results with their current short-range missile, the Sidewinder, the China Lake Naval Weapons Center began development of a dramatically improved missile to replace it. Studies had demonstrated two primary sources of misses; one was taking shots when the missile could not successfully track the target, and the other was when the missile ran out of fuel trying to chase down

1332-533: Was being developed, experience over Vietnam was clearly demonstrating that the idea of all-long-range combat was simply not possible given tactical limitations. The need for improved manoeuvrability over the lumbering FAD design was clear, and this developed into the VFX proposal that in turn produced the Tomcat. The need for a better short-range missile to equip it for times when the aircraft was forced to close on its target

1369-520: Was one of "quantity vs quality". Mock engagements showed that cheaper, lower-technology fighters armed with all-aspect missiles were able to destroy the more advanced, expensive F-15's and F-14's. These results of the AIMVAL/ACEVAL testing led to the Air Force decision to structure its fighter forces with a balance of cheaper F-16 's along with the more expensive F-15's, and the Navy took a similar strategy in procuring cheaper F/A-18 's along with

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