Avionics Needs Illities HUD HMD Dispalys

AVIONICS ENGINEERING
Mr.Sulthan
Assistant Professor
Department of Aerospace Engineering
Sanjay Ghodawat University, Kolhapur
Sanjay Ghodawat University,Kolhapur

AN OVERVIEW ON AVIONICS

AVIONICS
Combination of aviation and electronics
Avionics system or Avionics sub-system dependent on
electronics
Avionics industry- a major multi-billion dollar industry
world wide
Avionics equipment on a modern military or civil
aircraft account for around
 30% of the total cost of the aircraft
 40% in the case of a maritime patrol/anti-submarine aircraft (or
helicopter)
 Over 75% of the total cost in the case of an airborne early warning
aircraft such as an AWACS

• To enable the flight crew to carry out the aircraft
mission safely and efficiently.
• Mission is carrying passengers to their destination
(Civil Airliner).
• Intercepting a hostile aircraft, attacking a ground
target, reconnaissance or maritime patrol
(Military Aircraft).
AVIONIC SYSTEMS ARE
ESSENTIAL

• To meet the mission requirements with the minimum
flight crew (namely the first pilot and the second pilot)
• Economic benefits like
• Saving of crew salaries
• Expenses and training costs
• Reduction in weigh-more passengers or longer range on
less fuel
MAJOR DRIVER IN THE
DEVELOPMENT

• A single seat fighter or strike (attack) aircraft
is lighter
• Costs less than an equivalent two seat version
• Elimination of the second crew member
(navigator/observer/crew member)
• Reduction in training costs
IN THE MILITARY CASE

OTHER VERY IMPORTANT DRIVERS FOR
AVIONICS SYSTEMS ARE
• Increased safety
• Air traffic control requirements
• All weather operation
• Reduction in fuel consumption
• Improved aircraft performance and control and handling and
reduction in maintenance costs
• In the military case, the avionics systems are also being driven
by a continuing increase in the threats posed by the defensive
and offensive capabilities of potential aggressors.

AVIONICS SYSTEMS

AVIONICS SYSTEM
REQUIREMENTS

• Starting point for designing a digital Avionics system is a clear
understanding of the mission requirements and the requirement
levied by the host aircraft
• Top-level Requirement for Military
– The customer prepares the statement of need and top-level
description of possible missions
– Describes the gross characteristic of a hypothetical aircraft
that could fly the mission
– Customer may also describe the mission environment and
define strategic and tactical philosophies and principles and
rules of engagement.
Avionics System Design

Design is, in general,
a team effort
a large system integration activity
done in three stages
iterative
creative, knowledge based.
The three stages are:
Conceptual design
Preliminary design
Detailed design
PRELIMINARY THOUGHTS ON DESIGN

DOD-STD-2167A System Development Cycle

Aircraft Mission Requirements to Avionics
System Requirements

• What will it do?
• How will it do it?
• What is the general arrangement of parts?
• The end result of conceptual design is an
artist’s or engineer’s conception of the
vehicle/product.
• Example: Clay model of an automobile.
Conceptual Design

Conceptual Designs

• How big will it be?
• How much will it weigh?
• What engines will it use?
• How much fuel or propellent will it use?
• How much will it cost?
• This is what you will do in this course.
Preliminary Design

• How many parts will it have?
• What shape will they be?
• What materials?
• How will it be made?
• How will the parts be joined?
• How will technology advancements (e.g.
lightweight material, advanced airfoils,
improved engines, etc.) impact the design?
Detailed Design

Detailed Design

A380 Arrangement

• The designer needs to satisfy
– Customer who will buy and operate the vehicle
(e.g. Delta, TWA)
– Government Regulators (U.S. , Military, European,
Japanese…)
SPECIFICATION AND
STANDARDS

 Performance:
 Payload weight and volume
 how far and how fast it is to be carried
 how long and at what altitude
 passenger comfort
 flight instruments, ground and flight handling qualities
 Cost
 Price of system and spares, useful life, maintenance hours per flight
hour
 Firm order of units, options, Delivery schedule, payment schedule
CUSTOMER SPECIFICATIONS

 Civil
 FAA Civil Aviation Regulations define such things as required strength,
acoustics, effluents, reliability, take-off and landing performance,
emergency egress time.
 Military
 May play a dual role as customer and regulator
 MIL SPECS (Military specifications)
 May set minimum standards for Mission turn-around time, strength,
stability, speed-altitude-maneuver capability, detectability, vulnerability
TYPICAL GOVERNMENT
STANDARDS

 Aircraft/Spacecraft Design often involves integrating
parts, large and small, made by other vendors, into an
airframe or spaceframe (also called “the bus.”)
 Parts include
 engines, landing gear, shock absorbers, wheels, brakes, tires
 avionics (radios, antennae, flight control computers)
 cockpit instruments, actuators that move control surfaces, retract
landing gears, etc...
SYSTEM INTEGRATION

A380 Production

• Lot of Analyses
• Ground testing and simulation (e.g. wind
tunnel tests of model aircraft, flight simulation,
drop tests, full scale mock-up, fatigue tests)
• Flight tests
AEROSPACE DESIGN INVOLVES

• The aircraft manufacturer makes a very careful analysis of the
potential customer’s route structure, image , and operating
philosophies to determine the customer’s need and postulates a
future operating environment.
• The manufacturer then designs an aircraft that provides an
optimum, balance response to the integrated set of needs
• Safety is always the highest priority need and economical
operation is a close second.
Top-level Requirement for Civil Aircraft

 Five operational States for the flight control system:
Operational State I: Normal Operation
Operational State II: Restricted Operation
Operational State I: Minimum safe Operation
Operational State I: Controllable to an immediate
emergency landing
Operational State I: Controllable to an evaluable flight
condition
Requirements of MIL-F-9490

Probability of failures –FAR 25.1309

“Ilities” of Avionics System

 Capability
 Reliability
 Maintainability
 Certificability
 Survivability(military)
 Availability
 Susceptibility
 vulnerability
 Life cycle cost(military) or cost of ownership(civil)
 Technical risk
 Weight & power
Major Ilities of Avionics System

Capability:
How capable is avionics system?
can they do the job and even more?
Designer to maximize the capability of the system
within the constraints that are imposed.
Reliability:
Designer strives to make systems as reliable as
possible.
High reliability less maintenance costs.

Maintainability:
 Closely related to reliability
 System must need preventive or corrective maintenance.
 System can be maintained through built in testing, automated
troubleshooting and easy access to hardware.
 Availability:
 Combination of reliability and maintainability
 Trade of between reliability and maintainability to optimize availability.
 Availability translates into sorties for military aircraft and into revenue
flights for civil aircrafts.

Certificability:
 Major area of concern for avionics in civil airlines.
 Certification conducted by the regulatory agencies based on
detailed, expert examination of all facets of aircraft design and
operation.
 The avionics architecture should be straight forward and easily
understandable.
 There should be no sneak circuits and no noobvious modes of
operation.
 Avionics certification focus on three analyses: preliminary
hazard, fault tree, and FMEA.

 Survivability:
 It is a function of susceptibility and vulnerability.
 Susceptibility: measure of probability that an aircraft will be hit by a given
threat.
 Vulnerability: measure of the probability that damage will occur if there is
a hit by the threat
 Life cycle cost(LCC)or Cost of ownership:
 It deals with economic measures need for evaluating avionics architecture.
 It includes costs of varied items as spares acquisition, transportation,
storage and training (crew and Maintenance personnel's),hardware
development and test, depreciation and interest.

 Risk:
 Amount of failures and drawbacks in the design and
implementation.
 Over come by using the latest technology and fail proof technique
to overcome both developmental and long term technological risks.
 Weight and power:
 Minimize the weight and power requirements are two fundamental
concepts of avionics design.
 So the design must be light weight and power consuming which is
possible through the data bus and latest advancement of electronics
devices.

SONAR
RADAR
Military communications
Electro optics (FLIR or PIDS)
ECM OR ECCM
ESM/DAS
Integrated Avionics weapon
systems

• The term “glass cockpit” generally refers to an
LCD display that replaces the conventional
“six-pack” of flight instruments.
• It’s a term given to any aircraft in which the
primary instruments are located within a single
primary flight display (PFD) or Multi-Function
Display (MFD) that looks like a computer
Head Glass Cockpit

Cont.,
• PFDs and MFDs have the
capability to display all of
the traditional instruments
along with lots of additional
data such as engine data,
checklists, weather and
traffic displays.

• The typical six-pack on an older aircraft
includes six primary instruments (hence the
name ‘six-pack’),
• Airspeed indicator, (1knots=1nm/hr=
1.151mil/hr=1.852 km/hr =0.514m/s)
• Attitude Indicator,
• Altimeter,
• Vertical Speed Indicator,
Conventional Instruments/six-pack

Air speed Indicator Attitude Indicator Altimeter Indicator
Vertical speed Indicator Gyro Direction Indicator Turn Indicator

Cont.,
• In a glass cockpit, like the
popular Garmin G1000,
these instruments no longer
exist, and the data is
displayed digitally.

• The General Aviation Manufacturers
Association (GAMA) starts to define a glass
cockpit by defining what they call an
Integrated Flight Deck.
• Integration may also include display and
control of airborne surveillance, airplane
systems and engine systems.”
GAMA- General Aviation
Manufacturers Association

• GAMA’s definition of an integrated flight deck
states: “…at a minimum, an integrated
cockpit/flight deck must include electronic
display and control of all primary airplane
airspeed, altitude and attitude instruments, and
all essential navigation and communication
functions.
Cont.,

• The FAA doesn’t define the term glass cockpit, but the
organization does define a “technically advanced aircraft” or
TAA, as having an IFR-certified GPS or an MFD with
weather, traffic or terrain information, and an autopilot.
• The Garmin G1000 equipped aircraft falls into a class of
aircraft configurations referred by the Federal Aviation
Administration (FAA) as Technically Advanced Aircraft or
TAA.
FAA Rules

• Today’s aircraft have multiple interdependent
electronic displays that work together to give
the pilot all of the necessary data on one
screen.
• These glass cockpits are meant to be more
efficient for pilots,
• But can cause some problems if the pilot is
Glass cockpit Drawbacks

• Problems can arise for pilots who fail to
become completely familiar with the glass
cockpit technology and spend too much heads-
down time inside of the cockpit, figuring out
the computer’s functions.
• And too much heads-down time is even a
problem for pilots experienced with the

• The CRT is a display screen which produces images in the
form of the video signal.
• It is a type of vacuum tube which displays images when the
electron beam through electron guns are strikes on the
phosphorescent surface.
• In other Words, the CRT generates the beams, accelerates it at
high velocity and deflect it for creating the images on the
phosphorous screen so that the beam becomes visible.
Cathode Ray Tube (CRT)

CRT DISPLAY

• The working of CRT depends on the
movement of electrons beams.
• The electron guns generate sharply focused
electrons which are accelerated at high
voltage.
• This high-velocity electron beam when strikes
on the fluorescent screen creates luminous
Working

• These plates deflected the beams when the voltage applied
across it.
• The one pair of plate moves the beam upward and the second
pair of plate moves the beam from one side to another.
• The horizontal and vertical movement of the electron are
independent of each other, and hence the electron beam
positioned anywhere on the screen.
• The working parts of a CRT are enclosed in a vacuum glass
envelope so that the emitted electron can easily move freely
from one end of the tube to the other.

• The Electrons Gun Assembly, Deflection Plate
Assembly, Fluorescent Screen, Glass
Envelope, Base are the important parts of the
CRT.
• The electron gun emits the electron beam, and
through deflecting plates, it is strikes on the
phosphorous screen.
Construction of CRT

• The electron gun is the source of the electron beams. The
electron gun has a heater, cathode, grid, pre-accelerating
anode, focusing anode and accelerating anode.
• The electrons are emitted from the highly emitted cathode.
• The cathode is cylindrical in shape, and at the end of it, the
layer of strontium and barium oxide is deposited which emit
the high emission of electrons at the end of the tube.
• The electron passes through the electron in the small grid.
Electrons Gun Assembly

• This control grid is made up of nickel material with a centrally
located hole which is coaxial with the CRT axis.
• The electron which is emitted from the electron gun and passes
through the control grid have high positive potential
• which is applied across the pre-accelerating and accelerating
anodes.
• The beam is focused by focusing anode

• The pre-accelerating and accelerating anode are connected to
the positive high voltage of about 1500V and the focusing
anode are connected to the lower voltage of about 500V.
• There are two methods of focusing the electron beam. They
are
• Electrostatic Focusing Beam.
• Electromagnetic Focusing.

• The deflection plate produces the uniform electrostatic field
only in the one direction.
• The electron beam entering into the deflection plates will
accelerate only in the one direction.
• Hence electrons will not move in the other directions.
Electrostatic Deflection Plates

• The front of the CRT is called the face plate.
• The face plate of the CRT is made up of entirely fibre optics
which has special characteristics.
• The internal surface of the faceplate is coated with the
phosphor.
• The phosphorous converts the electrical energy into light
energy.
Screen For CRT

• The energy level of the phosphorous crystal raises when the
electron beams strike on it.
• This phenomenon is called cathode luminescence.
• The light which is emitted through phosphorous excitation is
called fluorescence.
• When the electron beam stop, the phosphorous crystal regain
their original position and release a quantum of light energy
which is called phosphorescence or persistence.

• It is a combination of two states of matter, the solid and the
liquid.
• LCD uses a liquid crystal to produce a visible image.
• Liquid crystal displays are super-thin technology display
screens that are generally used in laptop computer screens,
TVs, cell phones, and portable video games.
• LCD’s technologies allow displays to be much thinner when
compared to a cathode ray tube (CRT) technology.
LCD (Liquid Crystal Display)

LCDs Construction
• The basic structure of the
LCD should be controlled
by changing the applied
current.
• We must use polarized light.
• The liquid crystal should
able be to control both of
the operations to transmit or
can also able to change the
polarized light.

• As mentioned above that we need to take two
polarized glass pieces filter in the making of
the liquid crystal.
• The glass which does not have a polarized film
on the surface of it must be rubbed with a
special polymer that will create microscopic
grooves on the surface of the polarized glass
LCDs Construction

• Now we have to add a coating of pneumatic
liquid phase crystal on one of the polarizing
filters of the polarized glass.
• The microscopic channel causes the first layer
molecule to align with filter orientation.
• When the right angle appears at the first layer
piece, we should add a second piece of glass
with the polarized film.
• The first filter will be naturally polarized as the

• Thus the light travels through each layer and guided to the next
with the help of a molecule.
• The molecule tends to change its plane of vibration of the light
to match its angle.
• When the light reaches the far end of the liquid crystal
substance, it vibrates at the same angle as that of the final layer
of the molecule vibrates.
• The light is allowed to enter into the device only if the second
layer of the polarized glass matches with the final layer of the
molecule.

 Twisted Nematic Display
 In-Plane Switching Display
 Vertical Alignment Panel
 Advanced Fringe Field Switching (AFFS)
 Passive and Active Matrix Displays
Different Types of LCD

• The Passive-matrix type LCDs works with a simple grid so
that charge can be supplied to a specific pixel on the LCD.
• The grid can be designed with a quiet process and it starts
through two substrates which are known as glass layers.
• One glass layer gives columns whereas the other one gives
rows that are designed by using a clear conductive material
like indium-tin-oxide.
Passive and Active Matrix Displays

• Active Matrix LCD
– Each pixel is activated directly
• Turn or off individually
– Pixel have four transistors
• One each for red,green,blue
• One for opaqueness
– Animation is crisp and clean
– Quick pixel refresh rate
– Wider view angle.
Passive and Active Matrix Displays

• LCD’s consumes less amount of power
compared to CRT and LED
• LCD’s are consist of some microwatts for
display in comparison to some mill watts for
LED’s
• LCDs are of low cost
• Provides excellent contrast
Advantages

• Require additional light sources
• Range of temperature is limited for operation
• Low reliability
• Speed is very low
• LCD’s need an AC drive
Disadvantages

• The applications of liquid crystal display
include the following.
• Liquid crystal technology has major
applications in the field of science and
engineering as well on electronic devices.
• Liquid crystal thermometer
• Optical imaging
• The liquid crystal display technology is also
applicable in the visualization of the radio
frequency waves in the waveguide
Applications

• The orientation of an aircraft with respect to a
fixed inertial reference frame of axes is
defined by the three Euler angles.
Ψ – Yaw angle
ϴ – Pitch angle
Φ – Bank angle

Yaw angle(Ψ)
• clockwise rotation in the horizontal plane.

Pitch angle(ϴ)
• a clockwise rotation about the pitch axis.

Bank angle(Φ)
• a clockwise rotation about the roll axis.

ATTITUDE DERIVATION
• The measurement of the aircraft’s attitude
with respect to the horizontal plane in terms
of the pitch and bank angles and its heading,
that is the direction in which it is pointing in
the horizontal plane with respect to North, is
essential.

Measuring Euler angles
• There are two basic inertial mechanisations
which are used to derive the Euler angles to
the required accuracy.
– stable platform system
– strap-down system

Stable Platform System
• Stable platform system has the gyros and
accelerometers mounted on a platform which
is suspended in a set of gimbals.
• The gyros then control the gimbal servos so
that the platform maintains a stable
orientation in space irrespective of the aircraft
manoeuvres.
• Angular position pick-offs on the gimbals then
provide a direct read-out of the Euler angles.

Strap-down System
• Strap-down system has the gyros and
accelerometers mounted on a rigid frame or
block which is directly fixed, that is ‘strapped-
down’, to the airframe.
• The gyros and accelerometers thus measure
the angular and linear motion of the aircraft
with respect to the aircraft’s body axes.

Strap-down System
The Euler angles are then
computed from the body
rate information by the
system computer.

Horizontal Situation Indicator(HSI)
• The horizontal situation indicator (commonly called
the HSI) is an aircraft flight instrument mounted
below the artificial horizon in place of a
conventional heading indicator.
• It combines a heading indicator with a VHF
omnidirectional range-instrument landing
system(VOR-ILS) display.

• This reduces pilot workload by lessening the number
of elements in the pilot's instrument scan to the six
basic flight instruments.
• Among other advantages, the HSI offers freedom
from the confusion of reverse sensing on an
instrument landing system localizer back course
approach.
• As long as the needle is set to the localizer front
course, the instrument will indicate whether to fly
left or right, in either direction of travel.

• The heading indicator is usually slaved to a remote
compass and the HSI is frequently interconnected
with an autopilot capable of following the heading
select bug and of executing an ILS approach by
following the localizer and glide slope.

ATTITUDE AND HEADING REFERENCE
SYSTEM(AHRS)
• An attitude and heading reference system
(AHRS) uses an inertial measurement unit
(IMU) consisting of microelectromechanical
system (MEMS) inertial sensors to measure
the angular rate, acceleration, and Earth's
magnetic field.
• These measurements can then be used to
derive an estimate of the aircraft’s attitude.

• An AHRS typically includes a 3-axis gyroscope,
a 3-axis accelerometer, and a 3-axis
magnetometer to determine an estimate of a
system’s orientation.
• Each of these sensors contribute different
measurements to the combined system and
each exhibit unique limitations.

• In an AHRS, the measurements from the
gyroscope, accelerometer, and magnetometer
are combined to provide an estimate of a
system’s orientation.
• By combining the data from each of these
sensors into a Kalman filter, a drift-free, high-
rate orientation solution for the system can be
obtained.

Challenges of AHRS
• Challenges include
– transient and AC disturbances on the
accelerometer and magnetometer
– sustained dynamic accelerations
– internal and external magnetic disturbances.

Overcoming Challenges – Transient
disturbances
• Any type of transient or AC disturbance that
induces an acceleration or a magnetic
disturbance for a short period of time can be
almost completely mitigated through proper
tuning and reliance on the integrated gyro
through those time constants.

Overcoming Challenges – Sustained
acceleration
• The most common case where this becomes a
significant problem for an AHRS is when an aircraft is
operating in a banked turn.
• When this occurs, the accelerometer measures gravity
plus a long-term acceleration due to the centripetal
force created by traveling along a curved path.
• This results in a measurement vector that acts
perpendicular to the wings of the aircraft and cause
the AHRS to estimate a roll angle of zero while the
aircraft is in fact in a banked turn and thus has
significant roll relative to the horizon.

If an AHRS receives real-time measurements of
the velocity of the system, the sustained
dynamic acceleration can be estimated and
compensated for in the attitude estimation.

Overcoming Challenges – Magnetic
distrubances
• Magnetic disturbances lead to increased
errors in the magnetometer measurements,
causing errors in the estimates of the heading
angle. To account for any non-variable
magnetic disturbances internal to a system, a
hard and soft iron (HSI) calibration can be
preformed on the system.

INTRODUCTION SPECIFIC FORCE
MEASUREMENTS
• The acceleration of a vehicle can be
determined by measuring the force required to
constrain a suspended mass so that it has the
same acceleration as the vehicle on which it is
suspended, using
Newton’s law: force = mass × acceleration.

• The measurement of acceleration is
complicated by the fundamental fact that it is
impossible to distinguish between the force
acting on the suspended mass due to the
Earth’s gravitational attraction and the force
required to overcome the inertia and accelerate
the mass so that it has the same acceleration as
the vehicle.

Simple Spring Restrained Pendulous
Accelerometer

Simple Spring Restrained Pendulous
Accelerometer
• This comprises an unbalanced pendulous mass
which is restrained by the spring hinge so that it
can only move in one direction, that is along the
input axis.
• The spring hinge exerts a restoring torque which
is proportional to the angular deflection from the
null position.

• When the case is accelerated the pendulum deflects
from the null position until the spring torque is equal to
the moment required to accelerate the centre of mass of
the pendulum at the same acceleration as the vehicle.
• This simple type of accelerometer is typically oil filled
to provide viscous damping so that the transient
response is adequately damped.
• An electrical position pick-off measures the deflection
of the pendulum from the null position and provides the
output signal.

Closed-Loop Torque Balance
Accelerometer

• The accelerometer consists basically of a beam fabricated
from fused quartz which is suspended within the case by a
very low stiffness flexural hinge.
• Quartz exhibits zero hysteresis and consequent increased
bias stability compared with a metal spring hinge.
• A capacitive position pick-off is used to measure the
displacement of the pendulous mass from its null position.
• Torques are applied by means of a moving coil/permanent
magnet torque with the coils fixed to the beam.

• Thin flexible conducting ligaments enable electrical connections to
be made to the torquer coils and the capacitive pick-off plates.
• A mechanical damper is generally incorporated to supplement the
dynamic compensation in the capture amplifier in providing a well
damped response, typically around 0.5 critically damped.
• Bandwidth is typically around 500 Hz A temperature sensor is
generally incorporated in high accuracy accelerometers to enable
temperature dependent scale factor errors to be corrected.
• Typical size is around 2.54 cm (1 in) diameter and 2.54 cm (1 in)
length.

Skewed Axes Sensor Configurations

• Motion about any principal axis is sensed by
four sensors without loss of capability.
• The sensor supplies and electronics are entirely
independent, so that common failures are
precluded.

Gyroscope
• Gyroscope, device containing a rapidly spinning wheel
or circulating beam of light that is used to detect the
deviation of an object from its desired orientation.
• Gyroscopes are used in compasses and automatic pilots
on ships and aircraft, in the steering mechanisms of
torpedoes, and in the inertial guidance systems installed
in space launch vehicles, ballistic missiles, and orbiting
satellites.

Gyroscope in Aircraft Instruments
• In aircraft instruments, gyros are used in attitude,
compass and turn coordinators.
• These instruments contain a wheel or rotor
rotating at a high RPM which gives it two
important properties: rigidity and precession.
• The rotor or gyro can be electrically or vacuum /
pressure driven by a special pump on the engine.

Precession
• It associated with the action
of a gyroscope or a spinning
top and consisting of a
comparatively slow rotation
of the axis of rotation of a
spinning body about a line
intersecting the spin axis.

Rigidity
• Rigidity in space
describes the principle
that a gyroscope remains
in the fixed position on
the plane in which it is
spinning, unaffected by
the Earth's rotation. For
example, a bike wheel.

Instruments using gyroscope
• Normal instrument flight
relies in part on three
gyroscope instruments: an
attitude indicator (artificial
horizon), a heading
indicator (directional gyro,
or "DG") and a turn and slip
indicator ("needle and ball,"
or "turn and bank," or "turn
coordinator").

Attitude
Indicator
Gyro Direction
Indicator
Turn
Indicator

Heading Indicator
• The heading indicator or
directional gyro has an axis of
rotation that is set horizontally,
pointing north.
• Unlike a magnetic compass, it
does not seek north.
• When being used in an airplane,
for example, it will slowly drift
away from north and will need
to be reoriented periodically,
using a magnetic compass as a
reference.

Attitude indicator Gyro
• A typical round-dial attitude
indicator has an internal
gyroscope that is spun by your
plane's vacuum system.
• Air is pulled through the attitude
indicator's scooped rotor,
causing the gyroscope to spin.
• Mounted horizontally inside
your attitude indicator's casing is
a gyro that will spin in place.

Working
• The Attitude Indicator shows rotation about
both the longitudinal axis to indicate the
degree of bank, and about the lateral axis to
indicate pitch (nose up, level or nose down).
• It utilizes the rigidity characteristic of the gyro.

Turn indicator
• The turn indicator is a gyroscopic
instrument that works on the
principle of precession.
• The gyro is mounted in a gimbal.
• The gyro's rotational axis is in-line
with the lateral (pitch) axis of the
aircraft, while the gimbal has limited
freedom around the longitudinal
(roll) axis of the aircraft.

INFRARED APPLICATIONS IN
AVIONICS

• Infrared (IR) radiation is electromagnetic
radiation whose wavelength is longer than that of
visible light, but shorter than that of terahertz
radiation and microwaves.
• The name means "below red" (from the Latin
infra, "below"), red being the colour of visible
light with the longest wavelength.
• Infrared radiation has wavelengths between
about 750 nm and 1 mm, spanning three orders
of magnitude.
INFRRARED APPLICATIONS IN
AVIONICS

• Infrared is used in night vision equipment
when there is insufficient visible light to see.
• Night vision devices operate through a process
involving the conversion of ambient light
photons into electrons which are then
amplified by a chemical and electrical process
and then converted back into visible light.
APPLICATION – NIGHT VISION

• Infrared light sources can be used to augment the
available ambient light for conversion by night
vision devices, increasing in-the-dark visibility
without actually using a visible light source.
• The use of infrared light and night vision devices
should not be confused with thermal imaging
which creates images based on differences in
surface temperature by detecting infrared
radiation (heat) that emanates from objects and
their surrounding environment.

• Infrared radiation can be used to remotely
determine the temperature of objects (if the
emissivity is known).
• Thermographic cameras detect radiation in the
infrared range of the electromagnetic spectrum
and produce images of that radiation.
• Since infrared radiation is emitted by all objects
based on their temperatures, according to the
black body radiation law, thermography makes it
possible to "see" one's environment with or
without visible illumination.
APPLICATION - THERMOGRAPHY

• Infrared tracking, also known as infrared homing, refers
to a passive missile guidance system which uses the
emission from a target of electromagnetic radiation in
the infrared part of the spectrum to track it.
• Missiles which use infrared seeking are often referred
to as "heat-seekers", since infrared (IR) is just below
the visible spectrum of light in frequency and is
radiated strongly by hot bodies.
• Many objects such as people, vehicle engines and
aircraft generate and retain heat, and as such, are
especially visible in the infra-red wavelengths of light
compared to objects in the background.
APPLICATION - TRACKING

RADAR ALTIMETER AND
DOPPLER RADAR

• A radar altimeter, radio altimeter, low range
radio altimeter (LRRA) or simply RA measures
altitude above the terrain presently beneath an
aircraft or spacecraft.
• This type of altimeter provides the distance
between the plane and the ground directly below
it, as opposed to a barometric altimeter which
provides the distance above a pre-determined
datum, usually sea level.
RADAR ALTIMETER

• METHOD 1 - Radio waves are transmitted
towards the ground and the time it takes
them to be reflected back and return to the
aircraft is timed.
• METHOD 2 - The change in frequency of the
wave can be measured, the greater the shift
the further the distance travelled.
WORKING PRINCIPLE

• Radar altimeters are frequently used by
commercial aircraft for approach and landing,
especially in low-visibility conditions.
• Radio altimeters are an essential part in ground
proximity warning systems (GPWS), warning the
pilot if the aircraft is flying too low or descending
too quickly.
• However, radar altimeters cannot see terrain
directly ahead of the aircraft, only that directly
below it.

• Radar altimeters are also used in military
aircraft flying extremely low over terrain to
avoid radar detection and targeting by anti-
aircraft artillery or Surface-to-air Missiles.
• Radar altimeter technology is also used in
terrain-following radar allowing fighter aircraft
to fly at very low altitude.

• Moving target indication (MTI) is a mode of
operation of a radar to discriminate a target
against clutter.
• The most common approach is taking an
advantage of the Doppler effect.
• For a sequence of radar pulses the moving target
will be at different distance from the radar and
the phase of the radar return from the target will
be different for successive pulses, while the
returns from stationary clutter will arrive at the
same phase shift.
MOVING TARGET INDICATION
(DOPPLER RADARS)

• Radar is a system that uses electromagnetic waves to
identify the range, altitude, direction, or speed of both
moving and fixed objects such as aircraft, ships, motor
vehicles, weather formations, and terrain.
• The term RADAR was coined in 1941 as an acronym for
Radio Detection and Ranging.
• Radar was originally called RDF (Radio Direction Finder).
RADAR

• A radar system has a transmitter that emits either microwaves or
radio waves that are reflected by the target and detected by a
receiver, typically in the same location as the transmitter.
• Although the signal returned is usually very weak, the signal can be
amplified.
• This enables radar to detect objects at ranges where other emissions,
such as sound or visible light, would be too weak to detect.
• Radar is used in many contexts, including meteorological detection
of precipitation, measuring ocean surface waves, air traffic control,
police detection of speeding traffic, and by the military.

• Reflection
• Polarization
• Interference
• Noise
• Clutter
• Jamming
RADAR PRINCIPLES

• Radar waves scatter in a variety of ways
depending on the size (wavelength) of the radio
wave and the shape of the target.
• Early radars used very long wavelengths that were
larger than the targets and received a vague
signal, whereas some modern systems use shorter
wavelengths (a few centimetres or shorter) that
can image objects as small as a loaf of bread.
PRINCIPLES - REFLECTION

• If the wavelength is much shorter than the target's size, the wave
will bounce off in a way similar to the way light is reflected by a
mirror.
• If the wavelength is much longer than the size of the target, the
target is polarized (positive and negative charges are separated), like
a dipole antenna.
• This is described by Rayleigh scattering, an effect that creates the
Earth's blue sky and red sunsets.
• When the two length scales are comparable, there may be
resonances.
Cont.,

• Short radio waves reflect from curves and corners, in a way similar
to glint from a rounded piece of glass.
• The most reflective targets for short wavelengths have 90° angles
between the reflective surfaces.
• A structure consisting of three flat surfaces meeting at a single
corner, like the corner on a box, will always reflect waves entering
its opening directly back at the source.
• These is called corner reflectors are commonly used as radar
reflectors to make otherwise difficult-to-detect objects easier to
detect, and are often found on boats in order to improve their
detection in a rescue situation and to reduce collisions.
Cont.,

• Objects attempting to avoid detection will angle their
surfaces in a way to eliminate inside corners and avoid
surfaces and edges perpendicular to likely detection
directions, which leads to "odd“ looking stealth aircraft.
• These precautions do not completely eliminate reflection
because of diffraction, especially at longer wavelengths.
• The extent to which an object reflects or Scatters radio
waves is called its radar cross section.
Cont.,

• In the transmitted radar signal, the electric field is
perpendicular to the direction of propagation, and
this direction of the electric field is the
polarization of the wave.
• Radars use horizontal, vertical, linear and circular
polarization to detect different types of
reflections.
PRINCIPLES - POLARIZATION

• Circular polarization is used to minimize the
interference caused by rain.
• Linear polarization returns usually indicate metal
surfaces.
• Random polarization returns usually indicate a
fractal surface, such as rocks or soil, and are used
by navigation radars.
Cont.,

• Radar systems must overcome several different sources of
unwanted signals in order to focus only on the actual targets
of interest.
• These unwanted signals may originate from internal and
external sources, both passive and active.
• The ability of the radar system to overcome these unwanted
signals defines its signal-to-noise ratio (SNR).
PRINCIPLES - INTERFERENCE

• SNR is defined as the ratio of a signal power to the
noise power within the desired signal.
• Signal-to-noise ratio (SNR), compares the level of a
desired signal (such as targets) to the level of
background noise.
• The higher a system's SNR, the better it is in isolating
actual targets from the surrounding noise signals.
Cont.,

• Signal noise is an internal source of random variations
in the signal, which is inherently generated to some
degree by all electronic components.
• Noise typically appears as random variations
superimposed on the desired echo signal received in the
radar receiver.
• The lower the power of the desired signal, the more
difficult it is to discern it from the noise.
PRINCIPLES - NOISE

• Noise is also generated by external sources, most
importantly the natural thermal radiation of the
background scene surrounding the target of interest.
• In modern radar systems, due to the high performance
of their receivers, the internal noise is typically about
equal to or lower than the external scene noise.
• An exception is if the radar is aimed upwards at clear
sky, where the scene is so cold that it generates very
little thermal noise.
Cont.,

• Clutter refers to actual radio frequency (RF) echoes
returned from targets which are by definition
uninteresting to the radar operators in general.
• Targets mostly include natural objects such as ground,
sea, precipitation (such as rain, snow or hail), sand
storms, animals (especially birds), atmospheric
turbulence, and other atmospheric effects, such as
ionosphere reflections and meteor trails.
PRINCIPLES - CLUTTER

• Radar jamming refers to radio frequency signals
originating from sources outside the radar, transmitting
in the radar's frequency and thereby masking targets of
interest.
• Jamming may be intentional, as with an electronic
warfare (EW) tactic, or unintentional, as with friendly
forces operating equipment that transmits using the
same frequency range.
PRINCIPLES - JAMMING

• Jamming is considered an active interference source, since
it is initiated by elements outside the radar and in general
unrelated to the radar signals.
• Jamming is problematic to radar since the jamming signal
only needs to travel one way (from the jammer to the radar
receiver) whereas the radar echoes travel two ways(radar-
target-radar) and are therefore significantly reduced in
power by the time they return to the radar receiver.
Cont.,

• A radar altimeter, radio altimeter, low range radio
altimeter (LRRA) or simply RA measures altitude
above the terrain presently beneath an aircraft or
spacecraft.
• This type of altimeter provides the distance between the
plane and the ground directly below it, as opposed to a
barometric altimeter which provides the distance above
a pre-determined datum, usually sea level.
RADAR ALTIMETER

• METHOD 1 - Radio waves are transmitted
towards the ground and the time it takes them to
be reflected back and return to the aircraft is
timed.
• METHOD 2 - The change in frequency of the
wave can be measured, the greater the shift the
further the distance travelled.
WORKING PRINCIPLE

• Radar altimeters are frequently used by commercial aircraft
for approach and landing, especially in low-visibility
conditions.
• Radio altimeters are an essential part in ground proximity
warning systems (GPWS), warning the pilot if the aircraft is
flying too low or descending too quickly.
• However, radar altimeters cannot see terrain directly ahead
of the aircraft, only that directly below it.
Cont.,

• Radar altimeters are also used in military aircraft
flying extremely low over terrain to avoid radar
detection and targeting by anti-aircraft artillery or
Surface-to-air Missiles.
• Radar altimeter technology is also used in terrain-
following radar allowing fighter aircraft to fly at
very low altitude.
Cont.,

• Moving target indication (MTI) is a mode of operation of
a radar to discriminate a target against clutter.
• The most common approach is taking an advantage of the
Doppler effect.
• For a sequence of radar pulses the moving target will be at
different distance from the radar and the phase of the radar
return from the target will be different for successive pulses,
while the returns from stationary clutter will arrive at the
same phase shift.
MOVING TARGET INDICATION
(DOPPLER RADARS)

• Infrared (IR) radiation is electromagnetic radiation whose
wavelength is longer than that of visible light, but shorter than that
of terahertz radiation and microwaves and radio waves.
• The name means "below red" (from the Latin infra, "below"), red
being the colour of visible light with the longest wavelength.
• Infrared radiation has wavelengths between about 750 nm
(0.000001mm=1nm) to 1mm, spanning three orders of magnitude.
INFRRARED APPLICATIONS IN
AVIONICS

• Infrared is used in night vision equipment when
there is insufficient visible light to see.
• Night vision devices operate through a process
involving the conversion of ambient light photons
into electrons which are then amplified by a
chemical and electrical process and then
converted back into visible light.

• Infrared light sources can be used to augment the available
ambient light for conversion by night vision devices,
increasing in-the-dark visibility without actually using a
visible light source.
• The use of infrared light and night vision devices should not
be confused with thermal imaging which creates images
based on differences in surface temperature by detecting
infrared radiation (heat) that emanates from objects and
their surrounding environment.
Cont.,

• Infrared radiation can be used to remotely determine
the temperature of objects (if the emissivity is known).
• Thermographic cameras detect radiation in the infrared
range of the electromagnetic spectrum and produce
images of that radiation.
• Since infrared radiation is emitted by all objects based
on their temperatures, according to the black body
radiation law, thermography makes it possible to "see"
one's environment with or without visible illumination.
APPLICATION - THERMOGRAPHY

• Infrared tracking, also known as infrared homing, refers to a passive
missile guidance system which uses the emission from a target of
electromagnetic radiation in the infrared part of the spectrum to
track it.
• Missiles which use infrared seeking are often referred to as "heat-
seekers", since infrared (IR) is just below the visible spectrum of
light in frequency and is radiated strongly by hot bodies.
• Many objects such as people, vehicle engines and aircraft generate
and retain heat, and as such, are especially visible in the infra-red
wavelengths of light compared to objects in the background.
APPLICATION - TRACKING

RUNWAY LIGHTS AT AIRPORT: COLORS
AND MEANING EXPLAINED
• Every airport if it provides flight operations, has to be
equipped with the lighting system.
• Airport lighting system helps pilots to do landing and
takeoff safely at night, or in low visibility conditions.
• The critical part of airport lighting system is runway lights.
• They should be clearly visible, the should work
continuously in all operating conditions, and, of course,
they should be ICAO compliant (compliant with
international aviation regulations).

‘RUNWAY LIGHTS’ MEANING
• Airport runway is the most important part of an airfield where
aircraft does takeoff and landing.
• Runway has special markings identifying beginning and end of a
runway, touchdown point, location of a runway, etc.
• However, at night marking are not visible for pilots. That’s why
airport runway is additionally illuminated with runway lighting.
• The lights on a runway are of different types which will be
described later in this article.
• Every type of lights has its own meaning and plays its own role.

Approach Lights
• Approach lights are the first lights that pilot will ‘reach’ during
landing.
• They are of white color, unidirectional, blinking or steady type of
lights.
• Approach lights are located prior to the runway.
• Their main function is to ‘show’ in what direction the runway is.
• There are different type of runway approach.
• The simplest approach has a cross form and usually consists of 17
approach lights.
• This type approach lights is usually installed at regional and
domestic airports.
• The most advanced approach lighting system has a more
complicated structure and includes lights of few colors – white,
yellow, and red.
• You can see such system at huge air hubs like Dubai International
Airport, Atlanta Airport, or Heathrow Airport.

UNIT V
SURVEILLANCE &
COMMUNICATIONS SYSTEMS

Radio wave
• A radio wave used to transmit and receive
messages. A type of: radio emission, radio
radiation, radio wave. an electromagnetic wave
with a wavelength between 0.5 cm to 30,000 m.
• Electromagnetic waves or EM waves are waves
that are created as a result of vibrations between
an electric field and a magnetic field.

The Radio Spectrum
• The Radio Spectrum: ITU Frequency
Bands - VLF, LF, MF, HF, VHF, UHF .
• The International telecommunications Union,
ITU frequency bands define a set of portions
of the radio frequency spectrum: VLF, LF, HF,
VHF, UHF, EHF, etc.

Communication System
• It connects the flight deck to the ground and the
flight deck to the passengers.
• Radio transmitter and receiver equipment was the
first avionic system installed in an aircraft in 1909
manufactured by Marconi Company.
• The VHF aviation communication system works
on the air band of 108.00 MHz to 136.975 MHz.

• The concept of radio communication involves in transmission and
reception of electromagnetic energy waves through space.
• Alternating current passing through a conductor creates an EMF
around the conductor.
• If the frequency of alternating current increases, the energy stored
in the field is radiated into the space in the form of electromagnetic
waves. A conductor which radiates the energy is called as
transmitting antenna.
• These transmitted radio waves travel at a speed of 186000 miles per
second.

• If a radiated EMF passes through a conductor,
some of the energy in the field will cause the
electrons in motion, in the conductor.
• So this electron flow constitutes a current in
the receiving antenna which is similar to the
varying current in the transmitting antenna.

• Frequencies between 108 to 117.975 are splitted into 200 narrow
band channels and they are used for VOR, Automatic Terminal
information Service, ILS and Augmentation System.
• Frequencies between 118 – 137 MHz is splitted into 760 Channels
and they are used for AM voice transmission
• Some channels between 123.100 to 135.950 are available for
government agencies, search and rescue and National Aviation
authority use.
• Aircraft communication can also take place using HF i.e. for
transoceanic flights or satellite communication.

ITU frequency bands designations

ITU RADIO SPECTRUM BANDS WITH THEIR NAMES, WAVELENGTHS & FREQUENCIES
BAND NAME ABBREVIATION
ITU BAND
NUMBER
FREQUENCY WAVELENGTH
Extremely Low Frequency ELF 1 3 - 30 Hz 100000 - 10000 km
Super Low Frequency SLF 2 30 - 300 Hz 10000 - 1000 km
Ultra Low Frequency ULF 3 300 - 3000 Hz 1000 - 100 km
Very Low Frequency VLF 4 3 - 30 kHz 100 - 10 km
Low Frequency LF 5 30 - 300 kHz 10 - 1 km
Medium Frequency MF 6 300 - 3000kHz 1000 - 100 m
High Frequency HF 7 3 - 30 MHz 100 - 10 m
Very High Frequency VHF 8 30 - 300 MHz 10 - 1 m
Ultra High Frequency UHF 9 300 - 3000 MHz 100 - 10 cm
Super High Frequency SHF 10 3 - 30 GHz 10 - 1 cm
Extremely High Frequency EHF 11 30 - 300 GHz 10 - 1 mm
Tremendously High Frequency THF 12 300 - 3000 GHz 1 - 0.1 mm

Basic components of a Communication
System:
• a) Microphone
• It converts the sound energy into corresponding electrical energy.
• b) Transmitter
• (i) Oscillator – to generate RF signal
• (ii) Amplifier – increase the output
• (iii) Modulator – To add the voice signal
• c) Transmitting Antenna
• It is the special type of electrical circuit.
• d) Receiving Antenna
• e) Receiver
• f) Power supply.

Basic components of a Communication
System:
• The receiver must be able to select the desired
frequency signal from lot of signals present in
the air and also it should amplify the small ac
signal voltage.
• The receiver contains Demodulator (to remove
the added signal). The demodulator contains
detector (is used to AM) and discriminator (is

ACARS
• Aircraft communications addressing and reporting
system is a digital datalink system for transmission of
short, relatively simple messages between aircraft and
ground stations via radio or satellite.
• The protocol was designed by ARINC (Aeronautical
Radio, Incorporated) in 1978.
• Long Range Communication – HF (2 – 30 MHz)
• Near to Medium Range Communication – VHF (30 –
100 MHz)

Analog Modulation (AM)
• Amplitude modulation is the simplest and
earliest form of communication.
• AM is used to transmit the information via a
radio carrier.
• AM application including broadcasting in
medium and high frequency applications,
aircraft communications and CB Radio

Modulation
• The process by which some characteristics of a
carrier signal is varied in accordance with
message signal.
• Modulation is required to expand the
bandwidth of the transmitted signal for better
transmission quality. (To reduce noise and
Interference) Information (Low frequency such

Basic Principle of Analog Modulation
• Mix the voice frequencies with a radio frequency
signal, so that they are converted to radio
frequencies, which can propagate through free
space.
• Carrier – Sinusoidal High Frequency Radio
Signal.
• Voice Frequency + Carrier Frequency = Radio
Frequency

Antenna
• An Antenna (or sometimes called as an Aerial), is
an electrical device that converts electric power
into electromagnetic waves (or simply radio
waves) and vice-versa.
• A signal from a transmission line or the guiding
device (hence the term guided wave) like a co-
axial cable, is given to an antenna, which then
converts the signal into electromagnetic energy to
be transmitted through space (hence the term free

Cont.,
• Antenna can be used for both
Transmission and Reception of
electromagnetic radiation i.e. a
Transmitting Antenna with collect
electrical signals from a
transmission line and converts them
into radio waves whereas a
Receiving Antenna does the exact
opposite i.e. it accepts radio waves
from the space and converts them to
electrical signals and gives them to
a transmission line.

Why do we need Antennas?
• There are several reasons as to why we need or why we
use antennas, but an important reason as to why we use
antennas is that they provide a simple way to transfer
signals (or data) where other methods are impossible.
• For example, take the case of an aero plane. The pilot
needs to frequently communicate with the ATC
personnel.
• If would not make any sense if we tie up a cable (of

Cont.,
• Wireless communication is the only feasible
option and Antennas are the gateway for that.
• There are many situations or applications
where cables are preferred over wireless
communication with antennas (like high speed
Ethernet or the connection between gaming
console and the T.V., for example).

Different Types of Antennas
• Wire Antennas
– Short Dipole Antenna
– Dipole Antenna
– Loop Antenna
– Monopole Antenna
• Log Periodic Antennas
– Bow Tie Antennas
– Log-Periodic Antennas
– Log-Periodic Dipole Array

• Aperture Antennas
– Slot Antenna
– Horn Antenna
• Micro strip Antennas
– Rectangular Micro strip Patch Antenna
– Quarter-Wave Patch Antenna
• Reflector Antennas
– Flat-plate Reflector Antenna
– Corner Reflector Antenna
– Parabolic Reflector Antenna

• Lens Antennas
• Travelling-wave Antennas
– Long Wire Antenna
– Yagi–Uda Antenna
– Helical Wire Antenna
– Spiral Antenna
• Array Antennas
– Two-Element Array Antenna
– Linear Array Antenna
– Phased Array Antennas

Wire Antennas
• One of the most commonly used
antennas are wire antennas.
• They can be found in vehicles
(automobiles), ships, aircrafts,
buildings etc.
• Wire Antennas come in different
shapes and sizes like straight wire
(Dipole), Loop and Helix

Short Dipole Antenna
• Perhaps the simplest of all antennas is the Short Dipole
Antenna.
• It is a special case of the Dipole antenna.
• In its simplest form, it is basically an open circuit wire
with the signal being fed at the center.
• The term “short” in short dipole antenna doesn’t
directly refer to its size but rather to the size of the wire
relative to the wavelength of the signal.

• Dipole Antenna
– A Dipole Antenna is made up two conductors in the
same axis and the length of the wire need to be small
compared to the wavelength.
• Loop Antenna
– A Loop antenna is formed by a single or multiple turn
of wire forming a loop. The radiation produced by
loop antenna is high comparable to a short dipole
antenna.
 Monopole Antenna

Loop Antenna
Dipole Antenna
Monopole Antenna

Corner reflector Antenna
Parabolic reflector Antenna
Flatplate reflector Antenna

• These parameters are sometimes also called as Properties of
Antenna or Characteristics of Antenna. Certain basic
characteristics of antenna are listed below:
• Antenna Radiation Pattern
• Radiation Intensity
• Directivity and Gain
• Radiation Efficiency and Power Gain
Fundamental Parameters of Antennas
(Characteristics)

• Input Impedance
• Effective Length
• Bandwidth
• Effective Aperture
• Antenna Polarization
Fundamental Parameters of Antennas
(Characteristics)

• A radio or radar set that upon receiving a
designated signal emits a radio signal of its own
and that is used especially for the detection,
identification, and location of objects and in
satellites for relaying communications signals.
Transponder

• A transponder is a wireless communications,
monitoring, or control device that picks up and
automatically responds to an incoming signal.
The term is a contraction of the words
transmitter and responder. Transponders can be
either passive or active.
Uses of Transponders

• As a means to aid the identification of individual aircraft and
to facilitate the safe passage of aircraft through controlled
airspace.
• The ATC transponder allows ground surveillance radar to
interrogate aircraft and decode data, which enables correlation
of a radar track with a specific aircraft
Air traffic control systems (Mode S
transponder):

• A ground based primary surveillance radar (PSR)
will transmit radar energy and will be able to
detect an aircraft by means of the reflected
energy-termed the aircraft return.
• This will enable the aircraft return to be displayed
on an ATC console at a range and bearing
Principles of Transponder

• Coincident with the primary radar operation,
Secondary Surveillance radar (SSR) will transmit
a series of interrogation pulses that are received
by the on- board aircraft transponder. The
transponder aircraft replies with a different series
of pulses that gives information relating to the
Secondary Surveillance radar

• If the PSR and SSR are synchronized, usually by
being co-bore sighted, then both the presented
radar returns and the aircraft transponder
information may be presented together on the
ATC console.
• Air-to-air as well as air-to-ground
communication.
PSR and SSR

• A bus is a high-speed internal connection.
• Buses are used to send control signals and data
between the processor and other components.
BUS IN AVIONICS

• Three Types of buses
• Data Bus
• Address Bus
• Control Bus
TYPES OF BUSES

• Data bus is to carry information,
• An address bus to determine where it should
be sent.
• Control bus to determine its operation.
TYPES OF BUSES

• The Common Avionics Architecture System
(CAAS) Avionics Management System
integrates multiple communications,
navigation and mission subsystems through its
flexible Flight open systems architecture
design.
Avionics Architecture

Avionics System Architecture
• The architecture must conform to the overall
aircraft mission and design while ensuring that the
avionics system meets its performance
requirement.
• Establishing the basic architecture is the first and
the most fundamental challenge faced by the
designer.

Avionics Architecture Evolution
• First Generation Architecture (1940‟s –1950‟s)
– Disjoint or Independent Architecture (MiG-21)
– Centralized Architecture (F-111)
• Second Generation Architecture (1960‟s –1970‟s)
– Federated Architecture (F-16 A/B)
– Distributed Architecture (DAIS)
– Hierarchical Architecture (F-16 C/D, EAP)

Avionics Architecture Evolution
• Third Generation Architecture (1980‟s –
1990‟s)
– Pave Pillar Architecture (F-22)
• Fourth Generation Architecture (Past 2005)
– Pave Pace Architecture- JSF
– Open System Architecture.

• The early avionics systems were standalone black
boxes.
where each functional area had separate,
• Dedicated sensors,
• Processors
• Displays
• Interconnect media is point to point wiring.
First Generation - Disjoint Architecture

• The system was integrated by the air-crew.
• who had to look at various dials and displays connected
to disjoint sensors correlate the data provided by them.
• Apply error corrections,
• Arrange the functions of the sensors and
• Perform mode and failure management
In addition to flying the aircraft
First Generation - Disjoint Architecture

First Generation - Centralized
Architecture
• The digital technology evolved, a central computer was
added to integrate the information from the sensors and
subsystems.
• The central computing complex is connected to other
subsystems and sensors through analog, digital and other
interfaces.
• When interfacing with computer a variety of different
transmission methods are required and some of which needs
signal conversion (a/d).

First Generation - Centralized
Architecture
Advantages
• Simple Design
• Software can be written easily
• Computers are located in readily accessible bay.
Disadvantages
• Requirement of long data buses
• Low flexibility in software
• Increased vulnerability to change
• Different conversion techniques needed at Central Computer.
•

Second Generation – Federated
Architecture
Federated: (Join together, Become partners)
• In this SG-Federated Architecture, each system
acts independently but united (Loosely
Coupled).
• Data conversion occurs at the system level and
the data's are send as digital form – called
Digital Avionics Information Systems (DAIS)

Architecture
Sharing of Resources
• Use of TDMA-Time Division Multiple Access saves hundreds of
pounds of wiring
• Standardization of protocol makes the interchangeability of
equipment's easier
• Allows Independent system design and optimization of major
systems.
• Changes in system software and hardware are easy to make.
• Fault containment – Failure is not propagated

Architecture
Advantages
• It provides precise solutions over long range of
flight, weapon and sensor conditions
Disadvantages
• Profligate of resources

Second Generation – Distributed
Architecture
• It has multiple processors throughout the aircraft that are designed
for computing tasks on a real-time basis as a function of mission
phase and/or system status.
• Processing is performed in accordance with the sensors and
actuators.
Advantages
• Fewer, Shorter buses Faster program execution Intrinsic Partitioning
Disadvantages
• Potentially greater diversity in processor types which aggravates
software generation and validation.

• This architecture derived from the federated architecture.
• It is based on the TREE Topology.
Second Generation -Hierarchical
Architecture

• Critical functions are placed in a separate bus and Non- Critical functions
are placed in another bus.
• Failure in non – critical parts of networks does not generate hazards to the
critical parts of network.
• The communications between the subsystems of a particular group are
confined to their particular group.
• The overload of data in the main bus is reduced.
• Most of the military avionics flying today based on hierarchical
architecture.
Advantages

Comm
NAV
Radar
Independent Avionics (40’s - 50’s)
Comm
Radar
NAV
Mission
Mission
Federated Avionics (60’s - 70’s)

Integrated Avionics (80’s - 90’s)
Advanced Integrated Avionics
(Past 2000)
Comm
EW
Radar
Digital modulus
(Super computers)
Common
Analog modulus
Common
ASDN

• Pave Pillar is a US Air Force program to define the requirements and
avionics architecture for fighter aircraft of the 1990s.
The Program Emphasizes,
• Increased Information Fusion
• Higher levels and complexity of software
• Standardization for maintenance simplification
• Lower costs
• Backward and growth capability while making use of emerging technology
• Voice Recognition /synthesis and Artificial Intelligence.
Third Generation Architecture - PAVE
PILLAR

Advantages
• Component reliability gains
• Use of redundancy and resource sharing
• Application of fault tolerance
• Reduction of maintenance test and repair time
• Increasing crew station automation

Fourth Generation Architecture - PAVE
PACE
• US Air Force initiated a study project to cut
down the cost of sensors used in the fighter
aircraft.
• In 1990, Wright Laboratory – McDonnell
Aircraft, Boeing Aircraft Company and
Lockheed launched the Pave Pace Program
and Come with the Concept of Integrated

Advantages
• Modularity concepts cuts down the cost of the
avionics related to VMS, Mission Processing,
PVI and SMS
• The sensor costs accounts for 70% of the
avionics cost.
• Pave Pace takes Pave Pillar as a base line
standard

• It provides a medium for the exchange of data
and information between various Avionics
subsystems.
• It provides the Integration of Avionics
subsystems in military or civil aircraft and
spacecraft.
Data Bus

• Set of formal rules and conventions governing the
flow of information among the systems.
• Low level protocols define the electrical and
physical standards.
• High level protocols deal with the data
formatting, including the syntax of messages and
its format.
Protocol

• The MIL STD 1553B is a US military standard which
defines TDM(Time division multiplexing) multiple
source-multiple sink data bus system.
• It is widely used in military aircraft in many countries.
• It is also used in naval surface ships, submarines and
battle tanks.
• The system is a half duplex system.
MIL STD 1553B:

• The system was initially developed at Wright
Patterson Air Force base in 1970s.
• Published First Version 1553A in 1975
• Introduced in service on F-15 Programmed.
• Published Second version 1553B in 1978.
MIL STD 1553B:

• Bus Controller (BC)
• Remote Terminal (RT)
• Monitoring Terminal (MT)
• Transmission Media
Elements of MIL-STD-1553B

• The system is a command response system with all data
transmission being carried out under the control of the bus
controller.
• Each sub-system is connected to the bus through a unit
called a remote terminal (RT).
• Data can only be transmitted from one RT and received by
another RT following a command from the bus controller to
each RT.
MIL-STD-1553B

• The operation of the data bus system such that
information transmitted by the bus controller
or a remote terminal is addressed to more than
one of the terminals connected to the data bus
is known as the broadcast mode.
Broadcast Mode:

Types of Words
• Command words,
• Status words,
• Data words.

Types of Words
• A command word comprises six separate fields, they are;
SYNC, Terminal address, T/R, Sub address / Mode, Data word
Count/Mode Code and Parity bit.
• A status word is the first word of a response by an RT to a BC
command.
• It provides the summary of the status/health of the RT and also
the word count of the data words to be transmitted in response
to a command.
• A status word comprises four fields, they are; SYNC, Terminal
Address, Status field and Parity bit.

Types of Words
• The data words contain the actual data transmitted between stations.
• The data field is 16 bits.
• The SYNC signal is the inverse of the command and status word SYNCs.
• The most significant bit of the data is transmitted after the SYNC bits.
• There are ten possible transfer formats, but the three most commonly used
formats are,
– BC to RT
– RT to BC
– RT to RT

Combination of aviation and electronics
Avionics system or Avionics sub-system dependent on
electronics
Avionics industry- a major multi-billion dollar industry
world
wide
Avionics equipment on a modern military or civil
aircraft
account for around
 30% of the total cost of the aircraft
 40% in the case of a maritime patrol/anti-submarine aircraft
(or helicopter)
 Over 75% of the total cost in the case of an airborne early
warning aircraft
 such as an AWACS

To enable the flight crew to carry out the
aircraft
mission safely and efficiently
Mission is carrying passengers to their
destination
(Civil Airliner)
Intercepting a hostile aircraft, attacking a
ground
target, reconnaissance or maritime patrol
(Military
Aircraft)

To meet the mission requirements with
the minimum flight crew (namely the first
pilot and the second pilot)
Economic benefits like
Saving of crew salaries
Expenses and training costs
Reduction in weigh-more passengers or
longer
range on less fuel

IN THE MILITARY CASE
 A single seat fighter or strike (attack)
aircraft
is lighter
 Costs less than an equivalent two seat
version
 Elimination of the second crew member
(navigator/observer/crew member)
 Reduction in training costs

OTHER VERY IMPORTANT DRIVERS FOR
AVIONICS SYSTEMS ARE
Increased safety
Air traffic control requirements
All weather operation
Reduction in fuel consumption
Improved aircraft performance and
control and handling and reduction in
maintenance costs
* In the military case, the avionics systems are
also being
driven by a continuing increase in the threats
posed by the

• Starting point for designing a digital Avionics system is a clear
understanding of the mission requirements and the
requirement levied by the host aircraft
• Top-level Requirement for Military
– The customer prepares the statement of need and top-level
description of possible missions
– Describes the gross characteristic of a hypothetical aircraft that could
fly the mission
– Customer may also describe the mission environment and define
strategic and tactical philosophies and principles and rules of
engagement.
Avionics System Design

• Design is, in general,
– a team effort
– a large system integration activity
– done in three stages
– iterative
– creative, knowledge based.
• The three stages are:
– Conceptual design
– Preliminary design
– Detailed design
PRELIMINARY THOUGHTS ON DESIGN

DOD-STD-2167A System Development Cycle

Aircraft Mission Requirements to Avionics
System Requirements

• What will it do?
• How will it do it?
• What is the general arrangement of parts?
• The end result of conceptual design is an
artist’s or engineer’s conception of the
vehicle/product.
• Example: Clay model of an automobile.
Conceptual Design

Conceptual Designs
Dan Raymer sketch

Conceptual Designs
1988 Lockheed Desig

• How big will it be?
• How much will it weigh?
• What engines will it use?
• How much fuel or propellent will it use?
• How much will it cost?
• This is what you will do in this course.
Preliminary Design

Preliminary Design Analysis
Wing sizing spreadsheet
Written by Neal Willford 12/29/03 for Sport Aviation
Based on methods presented in "Technical Aerodynamics" by K.D. Wood, "Engineering Aerodynamics" by W.S. Diehl, and "Airplane Performance, Stability and Control" by Perkins and Hage
This spreadsheet is for educational purposes only and may contain errors. Any attempt to use the results for actual design purposes are done at the user's own risk.
Input required in yellow cells
Wing area sizing
A/C weight: 1150 lbs Flaps up Clmax: 1.42 get from Airplane CL page Background calculations
Desired stall speed: 45 knots, flaps up Flaps down Clmax: 1.78 get from Airplane CL page Cdo =
Desired stall speed: 39 knots, flaps down Lp =
Lt =
Minimum wing area needed to meet the flaps up and flaps down stall speed requirements. Use the larger of the two areas Ls =
Min. Wing Area = 125.3 sq ft, to meet desired flaps down stall speed lambda =
Min. Wing Area = 118.0 sq ft, to meet desired flaps up stall speed Wing AR =
Lt cnsspd =
Wing span sizing. Choose span to obtain desired rate of climb and ceiling lamda cnsspd=
Flat plate area: 4.00 sq ft Cs 3bl =
Total wing area: 122.4 sq ft L/Dmax =
Wingspan: 35.5 ft (upper wingspan for a biplane or wingspan for a monoplane)
estimated k1 = 1.00 biplane span factor Prop/body int=
Lower wingspan: 0 ft (lower wingspan for a biplane. Enter 0 for a monoplane) Propeller advance ratio, J =
Wing gap: 0 ft (distance between upper and lower wing if the a/c is a biplane. Enter 0 for a monoplane) T (fixed pitch)=
max fus width: 3.5 feet est airplane 'e'= 0.72 Oswald factor Tc (fixed pitch)=
Max horsepower: 79 bhp Max prop RPM: 2422.907489 T (constant speed)=
Prop W.R.: 0.066 chord/Diameter @ 75% prop radius Tc (constant speed)=
Peak Efficiency 2 Blade Prop Dia. = 66 inches Peak Efficiency Pitch = 63 inches R =
Propeller Diameter: 63 inches mu = 0.03 .03 concrete, .05 short grass, 0.1 long grass Dc =
Est Prop efficiency= 0.75 Vto/Vstall 1.15 ratio of takeoff speed to stall speed (1.15 to 1.2) Xt fixed pitch=
Prop efficiency: 0.75 ** iterate until equals estimated prop efficiency (then subtract .03 if using a wooden propeller) Ht fixed pitch=
Xt constant speed=
Estimated sea level standard day performance Ht constant speed=
Vmax = 127 mph = 110 knots Fixed Pitch Propeller Performance T.O. Speed=
V best ROC = 72 mph = 63 knots max ROC = 902 fpm
Vmax L/D = 65 mph = 56 knots Abs. Ceiling = 20557 feet
V min pwr = 49 mph = 43 knots Service Ceiling= 18277 feet
Vstall, clean = 50.9 mph = 44.2 knots Constant Speed Propeller Performance
Vstall, flaps = 45.4 mph = 39.4 knots max ROC = 1133 fpm
Wing loading= 9.4 lbs/sq ft Abs. Ceiling = 22899 feet
Power loading = 14.6 lbs/horsepower Service Ceiling= 20878 feet
Estimated takeoff and landing performance
Fixed Pitch Prop Constant Speed Prop
T.O. distance = 609 feet T.O. distance = 414 feet
T.O. over 50' = 929 feet T.O. over 50' = 686 feet
Landing distance ground roll = 420 feet, flaps down (1.15xVstall)
Landing over 50' obstacle = 1023 feet, flaps down (1.15xVstall)
Estimated power off sink rate (based on method in the March 1990 issue of Sport Aviation)
windmilling e: 0.48 APPROXIMATELY 2/3 of power on 'e'
min sink speed = 47 knots = 54 mph
sink rate = 506 ft/min
www.aero-siam.com/S405-WingDesig

• How many parts will it have?
• What shape will they be?
• What materials?
• How will it be made?
• How will the parts be joined?
• How will technology advancements (e.g.
lightweight material, advanced airfoils,
improved engines, etc.) impact the design?
Detailed Design

Detailed Design
Dassault Systems - CATIA

• The designer needs to satisfy
– Customer who will buy and operate the vehicle
(e.g. Delta, TWA)
– Government Regulators (U.S. , Military, European,
Japanese…)
SPECIFICATION AND STANDARDS

 Performance:
◦ Payload weight and volume
◦ how far and how fast it is to be carried
◦ how long and at what altitude
◦ passenger comfort
◦ flight instruments, ground and flight handling qualities
 Cost
 Price of system and spares, useful life, maintenance hours
per flight hour
 Firm order of units, options, Delivery schedule, payment
schedule
CUSTOMER SPECIFICATIONS

• Civil
– FAA Civil Aviation Regulations define such things as
required strength, acoustics, effluents, reliability, take-off
and landing performance, emergency egress time.
• Military
– May play a dual role as customer and regulator
– MIL SPECS (Military specifications)
– May set minimum standards for Mission turn-around time,
strength, stability, speed-altitude-maneuver capability,
detectability, vulnerability
TYPICAL GOVERNMENT STANDARDS

 Aircraft/Spacecraft Design often involves integrating
parts, large and small, made by other vendors, into
an airframe or spaceframe (also called “the bus.”)
 Parts include
◦ engines, landing gear, shock absorbers, wheels, brakes, tires
◦ avionics (radios, antennae, flight control computers)
◦ cockpit instruments, actuators that move control surfaces,
retract landing gears, etc...
SYSTEM INTEGRATION

• Lot of Analyses
• Ground testing and simulation (e.g. wind
tunnel tests of model aircraft, flight
simulation, drop tests, full scale mock-up,
fatigue tests)
• Flight tests
AEROSPACE DESIGN INVOLVES

• The aircraft manufacturer makes a very careful analysis of the
potential customer’s route structure, image , and operating
philosophies to determine the customer’s need and
postulates a future operating environment.
• The manufacturer then designs an aircraft that provides an
optimum, balance response to the integrated set of needs
• Safety is always the highest priority need and economical
operation is a close second.
Top-level Requirement for Civil Aircraft

• Five operational States for the flight control system:
– Operational State I: Normal Operation
– Operational State II: Restricted Operation
– Operational State I: Minimum safe Operation
– Operational State I: Controllable to an immediate
emergency landing
– Operational State I: Controllable to an evacuable flight
condition
Requirements of MIL-F-9490

• Essential : A function is essential if it’s loss degrades the flight
control system beyond operational state III.
• Flight Phase Essential :Same as essential except it applies only
during specific flight phases.
• Non-Critical :Loss of function does not effect flight safety or
reduce control capability beyond that required for operation
state III
Criticality Classification Definitions-9490

Probability of failures –FAR 25.1309

“Ilities” of Avionics System

• Capability
• Reliability
• Maintainability
• Certificability
• Survivability(military)
• Availability
• Susceptibility
• vulnerability
• Life cycle cost(military) or cost of ownership(civil)
• Technical risk
• Weight & power
Major Ilities of Avionics System

• Capability:
– How capable is avionics system?
– can they do the job and even more?
– Designer to maximize the capability of the system
within the constraints that are imposed.
• Reliability:
– Designer strives to make systems as reliable as
possible.
– High reliability less maintenance costs.
– If less reliable customer will not buy it and in
terms of civil airlines the certificating agencies will
not certify it.

• Maintainability:
– Closely related to reliability
– System must need preventive or corrective
maintenance.
– System can be maintained through built in testing,
automated troubleshooting and easy access to
hardware.
• Availability:
– Combination of reliability and maintainability
– Trade of between reliability and maintainability to
optimize availability.
– Availability translates into sorties for military
aircraft and into revenue flights for civil aircrafts.

• Certificability:
– Major area of concern for avionics in civil airlines.
– Certification conducted by the regulatory agencies
based on detailed, expert examination of all facets
of aircraft design and operation.
– The avionics architecture should be straight
forward and easily understandable.
– There should be no sneak circuits and no
noobvious modes of operation.
– Avionics certification focus on three analyses:
preliminary hazard, fault tree, and FMEA.

• Survivability:
– It is a function of susceptibility and vulnerability.
– Susceptibility: measure of probability that an
aircraft will be hit by a given threat.
– Vulnerability: measure of the probability that
damage will occur if there is a hit by the threat
• Life cycle cost(LCC)or Cost of ownership:
• It deals with economic measures need for evaluating
avionics architecture.
• It includes costs of varied items as spares acquisition,
transportation, storage and training (crew and
Maintenance personnel's),hardware development and
test, depreciation and interest.

• Risk:
– Amount of failures and drawbacks in the design
and implementation.
– Over come by using the latest technology and fail
proof technique to overcome both developmental
and long term technological risks.
• Weight and power:
– Minimize the weight and power requirements are
two fundamental concepts of avionics design.
– So the design must be light weight and power
consuming which is possible through the data bus
and latest advancement of electronics devices.

• SONAR
• RADAR
• Military communications
• Electro optics (FLIR or PIDS)
• ECM OR ECCM
• ESM/DAS
• Tactical missile guidance
Integrated Avionics weapon systems

• Microprocessor is a programmable integrated device that has computing and
decision-making capability similar to that of the central processing unit of the
computer.
• It is a multipurpose, programmable, clock-driven, register-based electronic device
that reads binary instructions from a storage device called memory, accepts binary
data as input and processes data according to those instructions, and provide
results as output.
Introduction:
Micro -
Processor
Memory
Input
Output

• Whereas Microcontroller that include all the components shown in the
previous figure on one chip.
• Examples include a wide range of products such as washing machines,
dishwashers, traffic light controllers, and automatic testing instruments.
Continued…..

Internal Architecture of Microprocessor

Microprocessor controlled temperature system

» 8-bit microprocessor
» Up to 8 MHz
» 64 KB RAM
» Single voltage
» On-chip peripherals
» 256 I/O ports
» 8080 object-code compatible
» Produced: From 1977 to 1990s
» Common manufacturer(s): Intel and several others
» Instruction set: pre x86
» Package(s): 40 pin DIP (Dual in-line package)
Introduction

Commparison with 8080
Features 8080 8085
Processor speed (MHz) 2 - 3.1 3 - 6
Power supply +5V, -5V and +12V +5V
On-chip peripherals
Clock oscillator
system controller
Serial I/O lines
Address/Data bus Separate address and data busses Multiplexed address and data
Pins/signals
Reset Out pin
RD bus signal
WR bus signal
IO/M bus signal
ALE pin provides encoded bus status
information
Interrupts
Three maskable interrupts and one
non-maskable
Instruction set
RIM - read interrupt mask
SIM - Set interrupt mask

Internal Registers and Flags of 8085A

 Accumulator or A register is an 8-bit register used for arithmetic, logic, I/O and
load/store operations.
 Flag is an 8-bit register containing 5 1-bit flags:
◦ Sign - set if the most significant bit of the result is set.
◦ Zero - set if the result is zero.
◦ Auxiliary carry - set if there was a carry out from bit 3 to bit 4 of the result.
◦ Parity - set if the parity (the number of set bits in the result) is even.
◦ Carry - set if there was a carry during addition, or borrow during subtraction/comparison.
 Stack pointer is a 16 bit register., it points to a memory location in R/W memory
canned the stack. The beginning of stack is defined by loading the 16 bit address in
the stack pointer.
 Program counter is a 16-bit register, it points to the memory address from which
the next byte is to be fetched, when the next byte is fetched the counter is
incremented by one and point to next location.
Registers

• General registers:
– 8-bit B and 8-bit C registers can be used as one 16-bit BC register pair. When used as a
pair the C register contains low-order byte. Some instructions may use BC register as a
data pointer.
– 8-bit D and 8-bit E registers can be used as one 16-bit DE register pair. When used as a
pair the E register contains low-order byte. Some instructions may use DE register as a
data pointer.
– 8-bit H and 8-bit L registers can be used as one 16-bit HL register pair. When used as a
pair the L register contains low-order byte. HL register usually contains a data pointer
used to reference memory addresses.
Registers

• Program, data and stack memories occupy the same memory space. The
total addressable memory size is 64 KB.
• Program memory - program can be located anywhere in memory. Jump,
branch and call instructions use 16-bit addresses.
• Data memory - the processor always uses 16-bit addresses so that data
can be placed anywhere.
• Stack memory is limited only by the size of memory. Stack grows
downward.
Memory

 The processor has 5 interrupts. They are presented below in the order of their priority
(from lowest to highest):
 INTR is maskable 8080A compatible interrupt. When the interrupt occurs the
processor fetches from the bus one instruction, usually one of these instructions:
 RST5.5 is a maskable interrupt. When this interrupt is received the processor saves
the contents of the PC register into stack and branches to 2Ch (hexadecimal) address.
the contents of the PC register into stack and branches to 34h (hexadecimal) address.
the contents of the PC register into stack and branches to 3Ch (hexadecimal) address.
 Trap is a non-maskable interrupt. When this interrupt is received the processor saves
the contents of the PC register into stack and branches to 24h (hexadecimal) address.
Interrupts

• 256 Input ports
• 256 Output ports
I/O ports

• Data moving instructions.
• Arithmetic - add, subtract, increment and decrement.
• Logic - AND, OR, XOR and rotate.
• Control transfer - conditional, unconditional, call subroutine, return from
subroutine and restarts.
• Input/Output instructions.
• Other - setting/clearing flag bits, enabling/disabling interrupts, stack operations,
etc.
Instruction Set

• Register - references the data in a register or in a register pair.
• Register indirect - instruction specifies register pair containing address, where the
data is located.
• Direct.
• Immediate - 8 or 16-bit data.
Addressing modes

• In many engineering schools in developing countries the 8085
processor is popularly used in many introductory
microprocessor courses.
• The 8085 processor has found marginal use in small scale
computers up to the 21st century.
• One niche application for the rad-hard version of the 8085 has
been in on-board instrument data processors for several NASA
and ESA space physics missions in the 1990s and early 2000s
Applications

AVIONICS SYSTEM ARCHITECTURE
Establishing the basic architecture is the first and
the most fundamental challenge faced by the
designer
These architectures rely on the data buses for intra
and intersystem communications
The architecture must conform to the overall aircraft
mission and design while ensuring that the avionics
system meets its performance requirements
The optimum architecture can only be selected
after a series of exhaustive design tradeoffs that
address the evaluation factors

AVIONICS ARCHITECTURE
First Generation Architecture ( 1940’s –1950’s)
Disjoint or Independent Architecture ( MiG-21)
Centralized Architecture (F-111)
Second Generation Architecture ( 1960’s –1970’s)
Federated Architecture (F-16 A/B)
Distributed Architecture (DAIS)
Hierarchical Architecture (F-16 C/D, EAP)
Third Generation Architecture ( 1980’s –1990’s)
Pave Pillar Architecture ( F-22)
Fourth Generation Architecture (Post 2005)
Pave Pace Architecture- JSF
Open System Architecture

FGA - DISJOINT ARCHITECTURE
The early avionics systems were stand alone black boxes where
each functional area had separate, dedicated sensors,
processors and displays and the interconnect media is point to
point wiring
The system was integrated by the air-crew who had to look at
various dials and displays connected to disjoint sensors
correlate the data provided by them, apply error corrections,
orchestrate the functions of the sensors and perform mode and
failure management in addition to flying the aircraft
This was feasible due to the simple nature of tasks to be
performed and due to the availability of time

Pilot
Navigation
Computer
Radar
Processor
Inertial
Measurement Unit
Altitude
Sensor
Display
…
Control
Panel
RF
….
Navigation
Panel
FGA - DISJOINT ARCHITECTURE

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