F-35 Specs

Autonomic Logistics (AL)
Because logistics support accounts for two-thirds of an aircraft's life cycle cost, the F-35 will achieve unprecedented levels of reliability and maintainability, combined with a highly responsive support and training system linked with the latest in information technology. The aircraft will be ready to fight anytime and anyplace. Autonomic Logistics (AL) is a seamless, embedded solution that integrates current performance, operational parameters, current configuration, scheduled upgrades and maintenance, component history, predictive diagnostics (prognostics) and health management, and service support for the F-35. Essentially, AL does invaluable and efficient behind-the-scenes monitoring, maintenance and prognostics to support the aircraft and ensure its continued good health.

Commonality Commonality is the key to affordability – on the assembly line; in shared-wing platforms; in common systems that enhance maintenance, field support and service interoperability; and in almost 100 percent commonality of the avionics suite. Component commonality across all three variants reduces unique spares requirements and the logistics footprint. In addition to reduced flyaway costs, the F-35 is designed to affordably integrate new technology during its entire life cycle.

Distributed Aperture System In a joint effort with Lockheed Martin Missiles and Fire Control, Northrop Grumman Electronic Systems will provide key electronic sensors for the F-35, which includes spearheading the work on the Electro-Optical Distributed Aperture System (DAS). This system will provide pilots with a unique protective sphere around the aircraft for enhanced situational awareness, missile warning, aircraft warning, day/night pilot vision, and fire control capability.

Diverterless Inlet The F-35's diverterless inlet lightens the overall weight of the aircraft. Traditional aircraft inlets were comprised of many moving parts and are much heavier than newer diverterless inlets. The diverterless inlet also eliminates all moving parts.

Electro-Optical Targeting System Lockheed Martin Missiles and Fire Control and Northrop Grumman Electronic Systems are jointly providing key electronic sensors for the F-35 to include the Electro-Optical Targeting System (EOTS). The internally mounted EOTS will provide extended range detection and precision targeting against ground targets, plus long range detection of air-to-air threats.

Helmet Mounted Display System Vision Systems International, LLC (VSI) is developing the most advanced and capable Helmet Mounted Display System (HMDS) for the F-35. Utilizing extensive design experience gained on successful production Helmet Mounted Displays (HMD), the F-35 HMDS will replace the traditional Head-Up-Display (HUD) while offering true sensor fusion.

Integrated Communications, Navigation and Identification Avionics
Northrop Grumman Space Technology's integrated avionics satisfy the requirements for greatly increased functionalities within extreme space and weight limitations via modular hardware that could be dynamically programmed to reconfigure for multiple functions. This "smart"-box approach delivers increased performance, quicker deployment, higher availability, enhanced scalability and lower life cycle costs.

Interoperability
The F-35 will have the most robust communications suite of any fighter aircraft built to date. The F-35 will be the first fighter to possess a satellite communications capability that integrates beyond line of sight communications throughout the spectrum of missions it is tasked to perform. The F-35 will contain the most modern tactical datalinks which will provide the sharing of data among its flight members as well as other airborne, surface and ground-based platforms required to perform assigned missions. The commitment of JSF partner nations to common communications capabilities and web-enabled logistics support will enable a new level of coalition interoperability. These capabilities allow the F-35 to lead the defense community in the migration to the net-centric warfighting force of the future.

Low Observability
An integrated airframe design, advanced materials and an axisymmetric nozzle maximize the F-35's stealth features.

Multi-Function Display System
An 8"x20" Multi-Function Display System (MFDS) will be the panoramic projection display for the F-35. MFDS employs leading edge technology in projection engine architecture, video, compression, illumination module controls and processing memory – all of which will make the MFDS the most advanced tactical display. One-gigabyte-per-second data interfaces will enable the MFDS to display six full motion images simultaneously. The adaptable layout will be easily reconfigurable for different missions or mission segments. Projection display technology will provide a high-luminance, high-contrast, and high-resolution picture with no viewing angle effect.

Multi-Mission Active Electronically Scanned Array (AESA) Radar
Northrop Grumman Electronic Systems is developing the Multi-Mission Active Electronically Scanned Array (AESA) Radar for the F-35. This advanced multi-function radar has gone through extensive flight demonstrations during the Concept Demonstration Phase (CDP). The radar will enable the F-35 JSF pilot to effectively engage air and ground targets at long range, while also providing outstanding situational awareness for enhanced survivability.

Propulsion
The F-35 Propulsion Systems are the most powerful fighter/attack turbofans in the world. There are two manufacturers with propulsion systems currently being tested. The propulsion systems are interchangeable and both will power the F-35. There are two major engine variants for the F-35. One engine will power the CTOL and CV versions of the aircraft, while the other will power the STOVL version. The F135 engine is made by Pratt & Whitney.

F135
The Pratt & Whitney F135 family of advanced propulsion systems utilize cutting edge technology to provide the F-35 with higher performance than conventional fighter aircraft. The engine consists of a 3-stage fan, a 6-stage compressor, an annular combustor, a single stage high-pressure turbine, and a 2 stage low-pressure turbine.

The F135 is currently in the SDD phase. The F135 is using the lessons learned from the F119 engine core and the JSF119 during the CDA stage to reduce risk in SDD. During SDD the F135 test engines will undergo a range of ground and flight tests to simulate various mission profiles. In these tests the system demonstration engines will be run for hours throughout various flight envelopes to ensure they meet performance requirements. One of the vital milestone tests occured at the end of 2003 with the first F135 engine to test.

The first CTOL F135 engine test occurred on 11 October 2003. The first STOVL F135 engine test occurred on 14 April 2004. To date over 2,000 hours have been accumulated on the F135 test engines.

Rolls-Royce Lift System
Rolls-Royce is subcontracted to Pratt & Whitney on the F135 to provide the Lift System for the F-35. The Lift System is comprised of the Lift Fan, Clutch, Drive Shaft, Roll Posts and the Three Bearing Swivel Module (3BSM).

Shaft Driven Lift Fan (SDLF)
Lockheed Martin developed the idea for a Short Take-Off Vertical Landing (STOVL) lift system that uses a vertically oriented Shaft Driven Lift Fan (SDLF). A two-stage low-pressure turbine on the engine provides the horsepower necessary to power the Rolls-Royce designed Lift Fan. The Lift Fan generates a column of cool air that provides nearly 20,000 pounds of lifting power using variable inlet guide vanes to modulate the airflow, along with an equivalent amount of thrust from the downward vectored rear exhaust to lift the aircraft. The Lift Fan utilizes a clutch that engages the shaft drive system for STOVL operations. Because the lift fan extracts power from the engine, exhaust temperatures are reduced by about 200 degrees compared to traditional STOVL systems.

The SDLF concept was successfully demonstrated through a Large Scale Powered Model (LSPM) in 1995-96 and during the flight-testing of the X-35B during the summer of 2001. The Lift Fan, a patented Lockheed Martin concept, was developed and produced by Rolls-Royce Corp. in Indianapolis, Indiana and in Bristol, England.

Robust Structure
Continuous tailhook-to-nose-gear structure and catapult-compatible nose gear launch system are strengthened for catapult and arresting loads.

Sophisticated Cockpit The F-35 provides its pilot with unsurpassed situational awareness, positive target identification and precision strike under any weather condition. Mission systems integration and outstanding over-the-nose visibility features are designed to dramatically enhance pilot performance.

Weapons Integration The F-35 will employ a variety of US and allied weapons. From JDAMs to Sidewinders to the UK Storm Shadow, the F-35 has been designed to carry either internally or externally a large array of weapons.

Laser Gyroscopes

1.          Introduction

Laser gyroscopes offer considerable advantages over their mechanical predecessors.  By utilising properties of wave mechanics and light, more durable^[1] devices with superior accuracy^[1] than the previous mechanical generation may be produced, with no moving parts^[1] and no maintenance required^[1].  These exhibit a high dynamic range for measurements of rotation about their central axis, often from thousandths of a degree per second[*]^[2] to tens^[1] of degrees per second, with typical sample rates near the order 100Hz^[1].

2.          Ring-laser gyroscopes (RLGs)

One common setup is a ring-laser, and (despite its name) often has a square or triangular cavity.  As light propagates in both directions around the "ring", the ring becomes a resonator.  Due to the finite speed of light, a continuous rotation of the ring alters the distances that each beam must travel to make a full circuit^[1].  In order to resonate, the frequencies of both beams must change to account for the altered circuit lengths^[1].  This change in path lengths can be detected by the spatial interference between the beams as they lose phase cohesion, or by the temporal interference due to the mixing of two slightly different frequencies (resulting in low-frequency “beating”)^[1].  This change in frequencies can be treated classically, as it is not a result of any relativistic Doppler effect (which cancels out due to the symmetry of the device^[3]).  Omissions between this simple model and practical implementations cause some minor problems, however these are easily solved without significantly increasing the complexity of the device.

While sources other than lasers have been used^[8] in passive gyroscopes, lasers provide narrower bandwidths than their alternatives, resulting in measurements that are more precise. The active gyroscopes, being ring-lasers, would not be possible without laser technology.

Now we will build a mathematical model of this device and derive some important equations that describe its operation.

2.1. Light resonating in a ring

Consider a beam of light, resonating around a closed ring (containing a gain medium) of circumference L, enclosing area A (Fig. A):

Fig. A             Light travelling around a circular path

A quick refresh of geometry reminds us:

The time taken for the light to make one pass round the loop, t_pass, is given by:

 ,
where c is the speed of light in the ring.

Now we mark a point along the ring α (which is at a distance r from a rotational axis).  If the ring is rotated at a constant angular velocity ω about the centre (Fig. B), the distance that the light must travel to make a full round-trip ‑ starting from α and finishing at α ‑ will be lengthened or shortened by the distance that α travels during that time.

Fig. B             Light travelling around a rotating circular path[†]

As the ring is a resonator, it must satisfy (periodic) boundary conditions, which requires it to fit an integral number of wavelengths of the beam into one rotation:

Therefore, a shift in resonant frequency must occur under rotation, to satisfy the new path length:

2.2. Two counter-propagating beams resonating in a rotating ring

We now introduce a second beam, almost identical to the first, but travelling in the opposite direction around the ring (Fig. C).  With no rotation, these will form simple standing waves in the ring, analogous to those formed in a typical laser cavity[‡]. 

Fig. C            Two counter-propagating beams in the ring

When the angular velocity of the ring is non-zero, a difference in perceived resonator-length emerges between the two beams, as shown in equation (115).  This causes the resonant frequencies for each direction of propagation to diverge according to equation (119).

For example, a device with a path in the shape of an equilateral triangle with 10 cm sides: A = 43 cm², L = 30 cm, using a HeNe gain medium (λ = 632.8 nm) will respond to a rotation rate of 0.01 ° s^-1 with a beat frequency of 16 Hz (beat period of 62 ms).

2.3. Realistic design for a ring-laser gyroscope

In reality, light does not typically travel in circular paths, and a completely closed loop would make measurements somewhat difficult. By splitting the "loop" as shown in Fig. D, the beating may be measured by a detector with a suitably high temporal resolution.

Fig. D       A typical laser gyroscope, with rotation Ω. Adapted from [6]

Here, the two beams are initially in-phase and have the same wavelength.  On application of a steady rotation, the resulting difference in path-lengths between the beams results in a phase difference^[4], which the lasing medium converts to a frequency difference^[5], causing the beating at the detector.

2.4. Enter the third dimension

If the axis of rotation is not perpendicular to the plane of the ring, the measured rate of rotation will be less than the actual rate of rotation, specifically:

Where the axis of rotation is unknown, three independent laser-gyroscopes may be mounted at right angles to each other, to provide triaxial rate-of-rotation measurements.  An example of such a device is pictured below (Fig. E):

Fig. E             "Three axis laser gyro", Prof. A E Siegman, Stanford University, retrieved on 10-Dec-2010 from:
http://www.stanford.edu/~siegman/ring_laser_gyros/Three%20axis%20laser%20gyro%20med.jpg

3.          Design Considerations

The model used so far is very simple, and lacks certain important features.  The effects of these omissions can cause the device to respond non-linearly, or not to respond at all to some small rotations.  Imperfections in the cavity are mostly responsible for the former problems, while the latter are due to interactions between the beams.

Fig. F             Different deviations from the ideal response curve for different sources of error
Adapted from [6]

3.1. Lock-in

Slight backwards scattering of the beams results in a small interaction between them in the resonator.  When the angular velocity of the system is small, the frequency difference between the beams is also very small, allowing this interaction to cause unintended mode-locking, where both beams will lock to the same frequency, as shown in Fig. G.  While this threshold rotation value can be calculated^[6]_, little can be done to prevent the mode-locking from occurring within that threshold.

Fig. G            The frequency shift (Δυ) vanishes for small rates of rotation (Ω) due to mode-locking.
Acquired from [6]

Application of an electric field across the lasing medium may utilise the Faraday effect to alter the polarisation^[6] of the beams in order to reduce their interaction, however this also alters the frequencies of the beams^[5], resulting in another source of potential error.

A different approach is to continuously rotate the system by a fixed amount (much larger than the threshold value), in order to keep the device's angular velocity out of mode-locking range.  Mechanical rotation introduces a lot of error in the measurements^[5], as the rate of mechanical rotation is not known exactly, or perfectly steady[§].  A more successful approach is "dithering": apply a small oscillation to the angular velocity.  There is no net measured effect of this when averaged over several oscillation cycles, as the clockwise rotation cancels out the anticlockwise rotation.  This oscillation reduces the amount of time that the angular velocity of the system is within the mode-locking threshold, allowing smaller rates of rotation to be measured.  One negative effect of this method is the production of non-linear "dead-bands", where the rotational frequency is an integer multiple of the "dithering" frequency^[5].

Finally, by oscillating the position of one of the cavity mirrors slightly, a Doppler shift can be introduced, increasing the spacing between the frequency of a back-scattered wave and the resonating wave propagating in the same direction^[6].

3.2. Null-shift

In a gas laser, atoms in the cavity circulate^[7][5], resulting in a slight variation of refractive index depending on the direction of a beam through the medium^[5].  This causes a slight frequency-shift between the two beams and a non-zero beat frequency when the system is stationary^[7].  This displaces the response curve of the device^[1].

One simple solution to this problem is to use two discharge tubes, discharging in opposite directions with respect to the beam path:

 

Fig. H            Two discharge tubes in the ring laser, with discharges directed in opposite directions in order to cancel out the frequency shift due to flowing of gain atoms.
Acquired from [5]

The frequency shifts from each tube are equal and opposite, cancelling out the null-shift.

3.3. Other error

Even with the previous corrections, noise and non-linear optical behaviour may cause the response of the device to deviate from a straight line.  A well-calculated choice of materials and good quality optics can reduce these errors.

4.          Fibre-optic gyroscopes (FOGs)

By not having a gain medium in the ring, the change in path-lengths will manifest as phase displacements rather than frequency shifts.  From equation (114) and the wave equation, the effects of the interference between these two shifted waves at the detector can be calculated:

[5]

Unfortunately, while high-precision detectors capable of detecting small changes in intensity may exist, very long paths may be needed in order to produce detectable changes in the intensity unless a fast rotational rate is expected.  For example, Michelson^[8] used a device with A = 0.21 km² to accurately measure the change in interference patterns due to the rotation of the Earth.

4.1. Theory

One simple way to vastly increase the enclosed area, without increasing the volume of the device to impractical values is to stack several loops:

 

Fig. I               Several broken loops, stacked and joined to form a coil

Fibre-optic cables provide a very cheap and convenient way to stack these areas; a coil of N turns, with each single turn enclosing area a provides an effective area A of Na.  The reduction in the number of optical components (particularly corner mirrors) combined with the wave-guiding properties of the fibres allows the creation of simple, robust devices requiring no calibration to find their zero-point.  As they use small changes in detected amplitude (due to interference), rather than variations in the time-domain (beating) to make measurements they are more susceptible to noise, however they are considerably cheaper to manufacture^[9] and suffer from no (or almost no) lock-in compared to ring laser gyroscopes.

As the laser source is external to the ring, solid-state lasers may be used in place of gas-lasers, considerably reducing the power consumption and voltages required for operation.

To provide an area similar to that of Michelson's device (see previous page), using loops enclosing 25 m² (approx 5.64 m in diameter), the number of turns needed would beN = 8,400.  As we would be using sensitive photodetectors and lasers with very narrow bandwidth and naturally high spatial coherence (instead of forcing coherence with slits as Michelson did), the number of turns needed could be reduced considerably.  Even without this, 8400 turns of a 0.4 mm thick[**] cable results in a coil depth of 3­­­–4 metres; this is far more convenient than Michelson's 0.21 km² single-loop[††].

4.2. Error sources in FOGs

Besides the usual sources of error in an optical system^[5], some error is due to power transfer between polarisations in the optic fibre, combined with birefringence, which causes a beam to interfere with itself^[5].  A highly birefringent fibre may be employed to reduce propagation of the unwanted polarisation.  Due to changes in the refractive index as light reaches the end of the fibre, the fibre may act as a weak resonator^[5].  This effect can be reduced by gradually changing the refractive index in several steps^[5].  The optical Kerr effect (interactions between the electric fields of the beams and the fibre medium) may cause varying phase changes that introduce more error: as with the ring laser gyroscope, a good choice of materials and optical components is essential.

While HeNe lasers typically have very narrow line-widths, diode lasers are being more commonly used in FOGs due to their lower power requirements, smaller size, better durability and reliability.

5.          Examples of modern laser gyroscope systems

5.1. Military

Due to the accuracy, robustness and low maintenance needs of optical gyroscope systems, they have been a large success with the military.  The notorious AC-130U gunship uses ring-laser gyroscopes^[10] in addition to standard GPS systems in order to provide fast directional information.

The primary inertial-reference system on the Boeing 777 uses Honeywell laser gyroscopes^[11], as do some of Boeing's other commercial planes including the 757 and the 767^[17].

Another interesting use is on a USAF anti-satellite missile: ASM‑135 ASAT, which also uses a Honeywell ring laser gyroscope^[12].

5.2. Commercial

An example of a discrete (fibre) laser gyroscope device is the Northrop Grumman LN-251^[13]: a durable six-kilogram device requiring a power of only twenty-five watts. It uses a single solid-state diode laser, and owes its accuracy to fibre-optic gyroscope(s) ^{[13], page 4}.

Another notable FOG is the KVH Industries DSP-1500^[14]: its sensing element is only 1.5 inches (~38 mm) in diameter^[14], coiled to a thickness of approximately 20 mm^[14], resulting in a unit weighing just forty grams^[14]!  Despite this, the device has a very wide range of operating environments^[15] and error of less than five degrees per hour^[15].  A two-axis variant of this device is also available^[14].

Toyota is also developing navigation systems for cars that utilise ring-laser gyroscopes^[16].

5.3. Scientific

The Canterbury Ring Laser (C-I)'s successor, C-II, encloses and area of one square metre^[18] by a cavity filled with helium and neon (forming a HeNe ring laser)^[18].  This was a prototype for a larger^[19] project (enclosing 16 m²) ­­— the "Gross Ring", which measures fluctuations in the rotation rate of the earth^[19] to within one part per billion^[19].

6.          Conclusion

As currently available technology is already capable of providing measurements to higher resolutions than are usually required and the laser gyroscopes are typically combined with other systems^[20] (such as GPS/GLONASS), large improvements of the underlying technology are unlikely to be of much importance in future development of it.  Instead, improved efficiency and miniaturisation are more likely, as the technology becomes embedded in increasingly mass‑produced consumer products such as cars and (size-depending) satellite-navigation devices and mobile phones.

With this in mind, the simpler power requirements, lower cost and lower part-count of FOGs (in comparison to ring‑laser devices) are likely to contribute far more to their popularity than their inferior resolution^[20] will do to impede it, while ring-laser devices will enjoy increasing use in high-precision situations such as scientific research.

Introduction to INS

Introduction to INS
A technology known as INS, or Inertial Navigation System originally developed in the mid 60s for Missile Guidence systems has undergone an extensive evolutionary process and has now been introduced into Civil Aviation. Aircraft such as the Boeing 747 are now fitted with INS systems. INS coupled with GPS (Global Positioning Systems) can be used to navigate by global Lattitude and Longitudinal co-ordinates and also allows for real-time calibration of the INS.


How does INS work?
Gimballed INS
Early IN systems used gravity and momentum. Gyros and accelorometers were mounted on rotating plates known as Gimballed Inertial Platforms, these gyros and motors can measure the change in angle on various axis,

Strapdown INS The 70s introduced Strapdown INS, which was similar in principal to the Early IN systems but had no moving parts, infact the gyros and accelerometers were fixed i.e strapped down, to the chassis/cicuitry of the equipment. The strapdown systems suffered from a major flaw in that power consumption was so high, thermal problems were introduced, making it unreliable.

and hence using electronic circuitry can calculate the position relative to the start, thus they cannot determine their initial location, just the change relative to it. The early IN systems relied heavily on a precision engineered mechanism. Left: Simplified Schematic Diagram of a Gimballed INS Mechanism. © GEC Marconi Above: Photo of Internals of a Gimballed Inertial  Platform INS Mechanism. © GEC Marconi

Ring Laser Gyro INS
RLG INS (Ring Laser Gyro INS), is another form of Strapdown INS (i.e has no reliance on a physical mechanism as such). RLG uses a solid state glass block with three drilled tubes, mirrors placed at each coner act as optical resonators and reflect the beam.

The tubes are filled with a Helium/Neon Halogen mixture and a High voltage (about 1Kv) is applied, just like a Tube-light or Cathode Ray tube in a Telivision set. RLG systems use two counter beams around the tube initially at the same frequency, as the unit is moved the distance each photon (sub atomic particle responsible for light) has to travel (to the next mirror) changes, resulting in a subtle change in Frequency of that beam. The frequency of the beam can be measured then the change in angle be calculated from Delta

Above: Simplified Schematic Diagram of a RLG INS System. © GEC Marconi

Frequency  (in this case the change in Frequency from before and after the unit was moved).

Left: Internals of the RLG System. Above: Housing and Circuitry of the RLG INS unit. © GEC Marconi

Current INS in Civil Aircraft
In the recent 10 years or so, precision engineering of mechanical parts has
improved dramatically making it possible to create accurate gimaballed
IN systems, which are currently being used in Civil Aviation Applications.
The computing power behind that of this INS is equivelant to the 68040
or 80486 (486) processor, and is far less than that of todays standard
home PC! - Bear that in mind next time your flying by 747!!

References / Acknowledgements
Special thanks to Anthony D. King of GEC Marconi for his excellent White paper and to the IEE (Institute of Electrical Engineers).

The Instrument Landing System

The Instrument Landing System

A. GENERAL DESCRIPTION
Instrument landing system (ILS) facilities are a highly accurate and dependable means of navigating to the runway in IFR conditions. When using the ILS, the pilot determines aircraft position primarily by reference to instruments. The ILS consists of:

1. the localizer transmitter;
2. the glide path transmitter;
3. the outer marker (can be replaced by an NDB or other fix);
4. the approach lighting system.

ILS is classified by category in accordance with the capabilities of the ground equipment. Category I ILS provides guidance information down to a decision height (DH) of not less than 200 ft. Improved equipment (airborne and ground) provide for Category II ILS approaches.
A DH of not less than 100 ft. on the radar altimeter is authorized for Category II ILS approaches.
The ILS provides the lateral and vertical guidance necessary to fly a precision approach, where glide slope information is provided. A precision approach is an approved descent procedure using a navigation facility aligned with a runway where glide slope information is given. When all components of the ILS system are available, including the approved approach procedure, the pilot may execute a precision approach.
B. LOCALIZER
1. GROUND EQUIPMENT: The primary component of the ILS is the localizer, which provides lateral guidance. The localizer is a VHF radio transmitter and antenna system using the same general range as VOR transmitters (between 108.10 MHz and 111.95 MHz). Localizer frequencies, however, are only on odd-tenths, with 50 kHz spacing between each frequency. The transmitter and antenna are on the centerline at the opposite end of the runway from the approach threshold.
The localizer back course is used on some, but not all ILS systems. Where the back course is approved for landing purposes, it is generally provided with a 75 MHz back marker facility or NDB located 3 to 5 NM from touchdown. The course is checked periodically to ensure that it is positioned within specified tolerances.
2. SIGNAL TRANSMISSION: The signal transmitted by the localizer consists of two vertical fan-shaped patterns that overlap, at the center (see ILS Localizer Signal Pattern figure, below). They are aligned with the extended centerline of the runway. The right side of this pattern, as seen by an approaching aircraft, is modulated at 150 Hz and is called the "blue" area. The left side of the pattern is modulated at 90 Hz and is called the "yellow" area. The overlap between the two areas provides the on-track signal.
The width of the navigational beam may be varied from approximately 3º to 6º, with 5º  being normal. It is adjusted to provide a track signal approximately 700 ft wide at the runway threshold. The width of the beam increases so that at 10 NM from the transmitter, the beam is approximately one mile wide.

The localizer is identified by an audio signal superimposed on the navigational signal. The audio signal is a two-letter identification preceded by the letter "I", e.g., " I-OW ".
The reception range of the localizer is at least 18 NM within 10º degrees of the on-track signal. In the area from l0º to 35º    of the on-track signal, the reception range is at least 10 NM. This is because the primary strength of the signal is aligned with the runway centerline.
3. LOCALIZER RECEIVER: The localizer signal is received in the aircraft by a localizer receiver. The localizer receiver is combined with the VOR receiver in a single unit. The two receivers share some electronic circuits and also the same frequency selector, volume control, and ON-OFF control.
The localizer signal activates the vertical needle called the track bar (TB). Assuming a final approach track aligned north and south (see ILS Localizer Signal Pattern figure, above), an aircraft east of the extended centerline of the runway (position 1) is in the area modulated at 150 Hz. The TB is deflected to the left. Conversely, if the aircraft is in the area west of the runway centerline, the 90 Hz signal causes the TB to deflect to the right (position 2). In the overlap area, both signals apply a force to the needle, causing a partial deflection in the direction of the strongest signal. Thus, if an aircraft is approximately on the approach track bur slightly to the right, the TB is deflected slightly to the left. This indicates that a correction to the left is necessary to place the aircraft in precise alignment.
At the point where the 90 Hz and 150 Hz signals are of equal intensity, the TB is centered, indicating that the aircraft is located precisely on the approach track(position 3).
When the TB is used in conjunction with the VOR, full scale needle deflection occurs 10º either side of the track shown on the track selector. When this same needle is used as an ILS localizer indicator, full-scale needle deflection occurs at approximately 2.5º from the center of the localizer beam.
Thus the sensitivity of the TB is approximately four times greater when used as a localizer indicator as opposed to VOR navigation.
In the localizer function, the TB does not depend on a correct track selector setting in Most cases; however, the pilot should set the track selector for the approach track as a reminder of the final approach.
When an OFF flag appears in front of the vertical needle, it indicates that the signal is too weak, and, therefore, the needle indications arc unreliable. A momentary OFF flag, or brief TB needle deflections, or both, may occur when obstructions or other aircraft pass between the transmitting antenna and the receiving aircraft.
C. GLIDE SLOPE EQUIPMENT
1. TRANSMITTER: The glide slope provides vertical guidance to the pilot during the approach. The ILS glide slope is produced by a ground-based UHF radio transmitter and antenna system, operating at a range of 329.30 MHz to 335.00 MHz, with a 50 kHz spacing between each channel. The transmitter is located 750 to 1,250 feet (ft) down the runway from the threshold, offset 400 to 600 ft from the runway centerline. Monitored to a tolerance of ± 1/2 degree, the UHF glide path is "paired" with (and usually automatically tuned by selecting) a corresponding VHF localizer frequency.
Like the localizer, the glide slope signal consists of two overlapping beams modulated at 90 Hz and 150 Hz (see Glide Slope Signal Pattern figure, below). Unlike the localizer, however, these signals are aligned above each other and are radiated primarily along the approach track. The thickness of the overlap area is 1.4º or .7º above and .7º below the optimum glide slope.

This glide slope signal may be adjusted between 2º and 4.5º above a horizontal plane. A typical. adjustment is 2.5º to 3º, depending upon such factors as obstructions along the approach path and the runway slope.
False signals may be generated along the glide slope in multiples of the glide path angle, the first being approximately 6º degrees above horizontal. This false signal will be a reciprocal signal (i.e. the fly up and fly down commands will be reversed). The false signal at 9º will be oriented in the same manner as the true glide slope. There are no false signals below the actual slope. An aircraft flying according to the published approach procedure on a front course ILS should not encounter these false signals.
2. SIGNAL RECEIVER: The glide slope signal is received by a UHF receiver in the aircraft. In modern avionics installations, the controls for this radio are integrated with the VOR controls so that the proper glide slope frequency is tuned automatically when the localizer frequency is selected.
The glide slope signal activates the glide slope needle, located in conjunction with the TB (see Glide Slope Signal Pattern figure, above). There is a separate OFF flag in the navigation indicator for the glide slope needle. This flag appears when the glide slope signal is too weak. As happens with the localizer, the glide slope needle shows full deflection until the aircraft reaches the point of signal overlap. At this time, the needle shows a partial deflection in the direction of the strongest signal. When both signals are equal, the needle centers horizontally, indicating that the aircraft is precisely on the glide path.
The pilot may determine precise location with respect to the approach path by referring to a single instrument because the navigation indicator provides both vertical and lateral guidance. In the Glide Slope Signal Pattern figure, above,   position 1, shows both needles centered, indicating that the aircraft is located in the center of the approach path. The indication at position 2 tells the pilot to fly down and left to correct the approach path. Position 3 shows the requirements to fly up and right to reach the proper path. With 1.4º of beam overlap, the area is approximately 1,500 ft thick at 10 nautical miles (NM), 150 ft at l NM, and less than one foot at touchdown.
The apparent sensitivity of the instrument increases as the aircraft nears the runway. The pilot must monitor it carefully to keep the needle centered. As said before, a full deflection of the needle indicates that the aircraft is either high or low but there is no indication of how high or low.
D. ILS MARKER BEACONS
l . GENERAL: Instrument landing system marker beacons provide information on distance from the runway by identifying predetermined points along the approach track. These beacons are low-power transmitters; that operate at a frequency of 75 MHz with 3 W or less rated power output. They radiate an elliptical beam upward from the ground. At an altitude of 1,000 ft, the beam dimensions are 2,400 ft long and 4,200 ft wide. At higher altitudes, the dimensions increase significantly.
2. OUTER MARKER (OM): The outer marker (if installed) is located 3 1/2 to 6 NM from the threshold within 250 ft of the extended runway centerline. It intersects the glide slope vertically at approximately 1,400 ft above runway elevation. It also marks the approximate point at which aircraft normally intercept the glide slope, and designates the beginning of the final approach segment. The signal is modulated at 400 Hz, which is an audible low tone with continuous Morse code dashes at a rate of two dashes per second. The signal is received in the aircraft by a 75 MHz marker beacon receiver. The pilot bears a tone over the speaker or headset and sees a blue light that flashes in synchronization with the aural tone (see the  Marker Beacon Lights figure, above right). Where geographic conditions prevent the positioning of an outer marker, a DME unit may be included as part of the ILS system to provide the pilot with the ability to make a positive position fix on the localizer. In most ILS installations, the OM is replaced by an NDB.
3. MIDDLE MARKER (MM): Middle markers have been removed from all ILS facilities in Canada bur are still used in the United States. The middle marker is located. approximately .5 to .8 NM from the threshold on the extended
runway centerline. The middle marker crosses the glide slope at approximately 200 to 250 ft above the runway elevation and. is near the missed approach point for the ILS Category l approach.
4. BACK MARKER (BM): The back course marker (BM), if installed, is normally located on the localizer back course approximately four to six miles from the runway threshold. The BM low pitched tone (400 Hz) is beard as a series of dots. It illuminates the aircraft's white marker beacon light. An NDB or DME fix can also be used and in most locations replace the BM.
E. LIGHTING SYSTEMS
1. GENERAL: Various runway environment lighting systems serve as integral parts of the ILS system to aid the pilot in landing. Any or all of the following lighting systems may be provided at a given facility: approach light system (ALS), sequenced flashing light (SFL), touchdown zone lights (TDZ) and centerline lights (CLL-required for Category II [Cat II] operations.)
2. RUNAWAY VISIBILITY MEASUREMENT: In order to land, the pilot must be able to see appropriate visual aids not later than the arrival at the decision height (DH) or the missed approach point (MAP).
Until fairly recently, the weather observer simply "peered into the murk", trying to identify landmarks at known distances from the observation point. This method is rather inaccurate; therefore, instrumentation was developed to improve the observer's capability.
The instrument designed to provide visibility information is called a transmissometer. It is normally located adjacent to a runway. The light source (see the Transmissometer figure, on the right) is separated from the photo-electric cell receiver by 500 to, 700 ft. The receiver, connected to the instrument readout in the airport tower, senses the reduction in the light level between it and the light source caused by increasing amounts of particulate matter in the air. In this way the receiver measures the relative transparency or opacity of the air. The readout is calibrated in feet of visibility and is called runway visual range (RVR).
3. RUNAWAY VISUAL RANGE (RVR): The RVR is the maximum distance in the direction of take-off or landing at which the runway or the specified light or markers delineating it can be seen from a height corresponding to the average eye-level of pilots at touchdown.
Runway visual range readings usually are expressed in hundreds of feet. For example, "RVR 24" means that the visual range along the runway is 2,400 ft. In weather reports, RVR is reported in a code: R36/4000 FT/D; meaning RVR for Runway 36 is 4000 ft and decreasing. Because visibility may differ from one runway to another, the RVR value is always given for the runway where the equipment is located. At times, visibility may even vary at different points along the same runway due to a local condition such as a fog bank, smoke, or a line of precipitation. For this reason, additional equipment may be installed for the departure end and mid-point of a runway.
Runway visual range reports are intended to indicate bow far the pilot can see along the runway in the touchdown zone; however, the actual visibility at other points along the runway may differ due to the siting of the transmissometer. The pilot should take this into, account when making decisions based on reported RVR.
Runway visual range is not reported unless the prevailing visibility is less than two miles or the RVR is 6,000 ft or less. This is so because the equipment cannot measure RVR above 6,000 ft. When it is reported, RVR can be used as an aid to pilots in determining what to expect during the final stages of an instrument approach. Instrument approach charts state the advisory values of visibility and RVR.
Runway visual range information is provided to the ATC arrival control. sector, the PAR position, and the control tower or FSS. It is passed routinely to the pilot when conditions warrant. RVR information may be included in aviation weather reports.
Ground visibility will continue to be reported and used in the application of take-off and landing minima. At runways with a transmissometer and digital readout equipment or other suitable means, RVR is used in lieu of prevailing visibility in determining the visibility minima unless affected by a local weather phenomenon of short duration.
The normal RVR reading is based on a runway light setting of strength 3. If the light settings are increased to strength 4 or 5, it causes a relative increase in the RVR reading. No decrease in the RVR reading is evident for light settings of less than setting 3. Pilots shall be advised when the runway light setting is adjusted to 4 or 5. If the RVR for a runway is measured at two locations, the controller identifies the touchdown location as "ALFA and the mid runway location as "Bravo".
In all cases, the pilot can request a light setting suitable for his or her requirements. When more than one aircraft is conducting an approach, the pilot of the second aircraft may request a change in the light setting after the first aircraft has completed its landing.
Because of the complex equipment requirements, RVR usually is only available at more active airports and not necessarily for all runways. If RVR equipment is not available or temporarily out of service for a given runway, the pilot uses the observer method to provide visibility information. In this case, the visibility is expressed as miles or fractions of a mile. The relationship between RVR values and visibility is shown below.
F. NDBs AT MARKER BEACON SITES
Additional aids may be available to assist the pilot in reaching the final approach fix. One of these aids is the NDB which can be co-located with or replace the outer marker (OM) or back marker (BM). It is a low-frequency non-directional beacon with a transmitting power of less than 25 watts (W) and a frequency range of 200 kilohertz (kHz) to 415 kHz. The reception range of the radio beacon is at least 15 nautical miles (NM). In a number of cases an en route NDB is purposely located at the outer marker so that it may serve as a terminal as well as an en route facility.
Find out about the history of NDBs here at http://www.navfltsm.addr.com/ndb-nav-history.htm

World’s current top 10 Jet Fighters

The World’s current top 10 Jet Fighters.

List compiled from Markosun combat avionics research and technical data base.

Modern Jet Fighters are the key to controlling the battlefield.  Since the introduction of the P-51 Mustang in WWII the U.S. has always put the upmost emphasis on air superiority.  If you control the air, you control the ground.

Modern Fighters are developed with cutting edge state of the art technology.  From stealth designs, advanced engines and pitch axis thrust vectoring.  Also new helmet mounted targeting displays make these jets more lethal.  But pilot training is still a major factor.

The U.S. air force, navy and marines practice more than any other military air arm in the world.  They have the financial resources to gas up the jets and keep the pilots practicing air to air combat on a regular basis.  The western Europeans and Japanese pilots also have comprehensive training.  The Russians have some of the best pilots in the world, but budget constraints don’t allow them to train as much as they would like.   The People’s Liberation Army Air Force of China only provides extra training to the elite pilots that fly their most advanced fighters such as the J-10.

Therefore many factors come into play when determining the best Fighter Jets in the World.

Move forward to the top ten list:

Number 10

F-18 E/F Super Hornet (USA)

• Maximum speed: Mach 1.8+ (1,190 mph, 1,900 km/h) at 40,000 ft (12,190 m)
• Range: 1,275 nmi (2,346 km) clean plus two AIM-9s
• Combat radius: 390 nmi (449 mi, 722 km) for interdiction mission
• Ferry range: 1,800 nmi (2,070 mi, 3,330 km)
• Service ceiling: 50,000+ ft (15,000+ m)
• Wing loading: 92.8 lb/ft² (453 kg/m²)
• Thrust/weight: 0.93

Number 9

J-10 (People’s Republic of China)

• Maximum speed: Mach 1.9 at altitude, Mach 1.2 at sea level
• g-limits: +9/-3 g (+88/-29 m/s², +290/-97 ft/s²)
• Combat radius:
  • On hi-lo-hi mission: 2,540 km (1,370 nautical miles) with 4,000lb/1,814kg bombload and two air-to-air missiles
  • On lo-lo-lo mission: 1,310 km (710 nautical miles with 4,000lb/1,814kg bombload and two air-to-air missiles
• Maximum range (without refueling): 3,400 km (2,113 mi) ()
• Service ceiling: 18,000 m (59,055 ft)
• Wing loading: 335 kg/m² (64 lb/ft²)

Number 8

Dassault Rafale  (France)

• Maximum speed:
  • High altitude: Mach 2 (1,290 knots)
  • Low altitude: 1,390 km/h, 750 knots
• Range: 3,700+ km (2,000+ nmi)
• Combat radius: 1,852+ km (1,000+ nmi) on penetration mission
• Service ceiling: 16,800 m (55,000 ft)
• Rate of climb: 304.8+ m/s (1,000+ ft/s)
• Wing loading: 326 kg/m² (83 1/3 lb/ft²)
• Thrust/weight: 1.13

Number 7

F-16 E Fighting Falcon  Block 60 (USA)

• Maximum speed:
  • At sea level: Mach 1.2 (915 mph, 1,470 km/h)
  • At altitude: Mach 2+ (1,500 mph, 2,414 km/h)
• Combat radius: 340 mi (295 nm, 550 km) on a hi-lo-hi mission with six 1,000 lb (450 kg) bombs
• Ferry range: 2,280 NM (2,620 mi, 4,220 km) with drop tanks
• Service ceiling: 60,000+ ft (18,000+ m)
• Rate of climb: 50,000 ft/min (254 m/s)
• Wing loading: approx 40 lb/ft² (430 kg/m²)
• Thrust/weight: 1.095

Number 6

Mig-35 (Russia)

• Maximum speed: Mach 2.25 (2,400 km/h, 1,491 mph) at altitude
• Range: 2,000 km (1,240 mi)
• Ferry range: 3,100 km (1,930 mi) with 3 external fuel tanks
• Service ceiling: 17,500 m (57,400 ft)
• Rate of climb: 330 m/s (65,000 ft/min)
• Thrust/weight: 1.03

Number 5

Su-27  (Russia)

• Maximum speed: Mach 2.35 (2,500 km/h, 1,550 mph) at altitude
• Range: 3,530 km (2,070 mi) at altitude; (1,340 km / 800 mi at sea level)
• Service ceiling: 18,500 m (62,523 ft)
• Rate of climb: 300 m/s (64,000 ft/min)
• Wing loading: 371 kg/m² (76 lb/ft²)
• Thrust/weight: 1.09

Number 4

F-15 C/D Eagle (USA)

• Maximum speed:
  • High altitude: Mach 2.5+ (1,650+ mph, 2,660+ km/h)
  • Low altitude: Mach 1.2 (900 mph, 1,450 km/h)
• Combat radius: 1,061 nmi (1,222 mi, 1,967 km) for interdiction mission
• Ferry range: 3,450 mi (3,000 nmi, 5,550 km) with conformal fuel tanks and three external fuel tanks
• Service ceiling: 65,000 ft (20,000 m)
• Rate of climb: >50,000 ft/min (254 m/s)
• Wing loading: 73.1 lb/ft² (358 kg/m²)
• Thrust/weight: 1.12 (-220), 1.30 (-229)

Number 3

Su-35 (Russia)

• Maximum speed: Mach 2.25 (2,410 km/h, 1,500 mph) at altitude
• Range: 3,600 km (1,940 nmi) ; (1,580 km, 850 nmi near ground level)
• Ferry range: 4,500 km (2,430 nmi) with external fuel tanks
• Service ceiling: 18,000 m (59,100 ft)
• Rate of climb: >280 m/s (>55,100 ft/min)
• Wing loading: 408 kg/m² (84.9 lb/ft²)
• Thrust/weight: 1.14

Number 2

Eurofighter Typhoon  (U.K., Germany, Italy, Spain)

• Maximum speed:
  • At altitude: Mach 2+ (2,495 km/h, 1,550 mph)
  • At sea level: Mach 1.2 (1470 km/h / 913.2 mph)
  • Supercruise: Mach 1.1-1.5
• Range: 2,900 km (1,840 mi)
• Combat radius:
  • Ground attack, lo-lo-lo: 601 km (373 nmi)
  • Ground attack, hi-lo-hi: 1,389 km (863 nmi)
  • Air defence with 3-hr CAP: 185 km (115 nmi)
  • Air defence with 10-min loiter: 1,389 km (863 mi)
• Ferry range: 3,790 km (2,300 mi)
• Service ceiling: 19,810 m (65,000 ft)
• Rate of climb: >315 m/s (62,000 ft/min)
• Wing loading: 307 kg/m² (63 lb/ft²)

Number 1

F-22 Raptor (USA)

• Maximum speed:
  • At altitude: Mach 2.25 (1,500 mph, 2,410 km/h)
  • Supercruise: Mach 1.82 (1,220 mph, 1,963 km/h)
• Range: 1,600 nmi (1,840 mi, 2,960 km) with 2 external fuel tanks
• Combat radius: 410 nmi (471 mi, 759 km)
• Ferry range: 2,000 mi (1,738 nmi, 3,219 km)
• Service ceiling: 65,000 ft (19,812 m)
• Wing loading: 77 lb/ft² (375 kg/m²)

• Thrust/weight: 1.08 (1.26 with loaded weight & 50% fuel)
• Maximum g-load: -3.0/+9.0 g

                                                                                                                                                                                                                                                       

Not on the top ten list, but worthy of mention is the SU-30 MKI from the Indian Air Force

Related posts:  http://markosun.wordpress.com/2012/09/16/fifth-generation-fighter-jets/

http://markosun.wordpress.com/2012/07/22/fighter-jets-with-the-coolest-nicknames/

http://markosun.wordpress.com/2012/03/20/jump-jets/

http://markosun.wordpress.com/2011/02/03/new-fighter-jet-camouflage-schemes/