3. AIRCRAFT NAVIGATION SYSTEMS INCLUDE â
ďź VHF OMNIDIRECTIONAL RANGE (VOR)
ďź INSTRUMENT LANDING SYSTEM (ILS)
ďź DISTANCE MEASURING EQUIPMENT (DME)
ďź AUTOMATIC DIRECTION FINDERS (ADF)
ďź DOPPLER NAVIGATION SYSTEM
ďź INERTIAL NAVIGATION SYSTEM
4. VHF OMNIRANGE SYSTEM
ďźElectronic navigation system.
ďź It produces 360 usable radials or courses ,any one
of which is radial path connected to the station.
ďź Operation is in the vhf portion of the radio
spectrum.
ďź Frequency range 108 MHz-117.95 MHz
5. ďś BENEFITES
ď§ More accurate and precise flying
ď§ Reliable
ď§ Voice capable
ď§ Reduces interference from atmosphere
and precipitation
ďź Navigation info is visually displayed on an
instrument in cockpit called the CDI (course
deviation indicator.)
7. VOR RECEIVING SYSTEMS CONSIST OF
ďź A RECEIVER
ďź VISUAL INDICATOR
ďź ANTENNAS
ďź A POWER SUPPLY
ďź FREQUENCY SELECTOR: USED TO TUNE RECEIVER
TO SELECTED VOR GROUND STATION
INFO FROM THE VOR RECEIVER IS DISPLAYED ON THE
CDI (COURSE DEVIATION INDICATOR).
8.
9. WORKING OF VOR
ďź Info from the VOR receiver is displayed on the CDI
(Course Deviation Indicator).
ďźThe vertical needle is used as the course indicator.
ďź Vertical needle also indicates when the aircraft
deviates from the course and
ďź The direction of the aircraft must be turned to attain
the desired course.
10.
11. WORKING OF VOR THROUGH CDI
ďź To-from indicator presents the direction to or from
the station along the omni radial.
ďź When the localizer signals are selected on the
receiver ,the indicator shows the position of the
localizer beam relative to the aircraft and the
direction the aircraft must be turned to intercept the
localizer.
ďź During VOR operation the VOR radial to be used is
selected by rotating the OBS (omni-bearing selector).
ďź OBS is graduated in degrees from 0 to 360.
12. INSTRUMENT LANDING SYSTEM (ILS)
ďźOperates in the VHF portion of the electromagnetic
spectrum
ďźSystem consists of a runaway localizer, a glide slope
signal, and marker beacons for position location
ďźLocalizer equipment produces a radio course aligned
with the centre of an airport runaway. The on course
signals result from the equal reception of two signals;
Blue sector(150 Hz) and yellow sector(90 Hz)
14. ďźThe glide slope : assists pilot in making the correct
angle of descent
ďźGlide slope signals are radiated from two antennas
located adjacent to the touchdown point of the
runway.
ďźInfo from both localizer and glide slope receivers is
presented to the CDI;
THE COURSE DEVIATION INDICATOR
ďźThe vertical needle: localizer information
ďźHorizontal needle : Glide slope information
When both needles are centered, the aircraft is on
course and descending at the proper rate
15. MARKER BEACONS
ďźIn connection with the instrument landing system.
ďźsignals which indicate the position of the aircraft
along the approach to the runway
ďźThree markers are used in each installation:
ďOuter marker - the beginning of the approach path
is modulated by a 400 HZ signal, a tone keyed in
long dashes
ďMiddle marker: 3500 ft from the end of the runway
is modulated at 1300 Hz, a higher-pitched tone
16.
17. DISTANCE MEASURING EQUIPMENT(DME)
ďźConstant visual indication of the distance the aircraft
is from a ground station
ďźNOT a true indication of point to point distance as
measured over the ground
ďźIndicates the slant range between the aircraft and
the ground station
18. WORKING OF DME
ďźTransceiver transmits a pair of spaced pulses to the
ground station
ďźGround station responds with a pulse transmission
on a separate frequency to send a reply to the aircraft
ďźTime elapsed is time between the challenges and
are measured;
ďźTime travel is the distance separating plane and
station.
ďźDistance is indicated in ânautical milesâ by a cockpit
instrument
19. ďź Transmitting frequencies are in 2 groups
ď 962 MHz to 1024 MHz
ď 1151 MHz to 1212 MHz
ď Receiving frequency is between 1025 to 1149 MHz
Aircraftâs DME transceiver is tuned to the selected DME
ground station
20. AUTOMATIC DIRECTION FINDERS
ďźRadio receivers equipped with directional antennas
ďźUsed to determine the direction from which signal
are received
ďźProvide controls for manual operation in addition to
automatic direction finding.
ďźProvide a means of fixing the position with
reasonable accuracy.
ďźOperates in low and medium frequency spectra 190
kHz through 1750 kHz.
21.
22. ďźConsists of
ď§ Receiver, Loop antenna,
ď§ Sense or non-directional antenna,
ď§ Indicator and control unit.
ďźLoop antenna rotates through 360 degrees
ďźReceives Max signal strength:
In parallel position with the direction of the
transmitted signal
ďźReaches the Min when perpendicular to the
transmitted signal position of the loop, is called the
null position
23. ďźNull position of the loop is used for direction finding
ďźTwo null positions exist (180 degrees apart)
ďźLoop antenna cannot differentiate, require sense
antenna
ďźSignal strength of the sense antenna is superimposed
with the null antenna
ďźOnly one null position of the loop
24. DOPPLER NAVIGATION SYSTEM
ďźAutomatically and continuously computes and
displays ground speed and drift angle of an aircraft
without the aid of ground stations, wind estimates
or true air speed data
ďźDoes not sense direction as search radar does
ďźUses continuous carrier wave transmission energy
and determines the forward and lateral velocity
component of the air craft by utilizing the principle
known as DOPPLER EFFECT
25. INERTIAL NAVIGATION SYSTEM
ďźUsed on large aircraft as a long range navigation aid
ďźSelf-contained system; DOES NOT require any signal
inputs from ground navigational facilities
ďźDerives altitude, velocity, and heading information
from measurement of the aircraftâs accelerations
ďśTwo accelerometers are required,
one referenced towards east and other towards north.
ďźThe accelerometers are mounted on a gyro stabilized
unit, called the stable platform
ďźAverts the introduction of errors resulting from the
acceleration due to gravity.
26.
27. An inertial navigation system is a complex containing
four basic components :ďźA stable platform which is oriented to maintain
accelerometers horizontal to the earthâs surface.
ďźAccelerometers arranged on the platform to
supply specific components of acceleration
ďźIntegrators which receive the output from the
accelerometers and furnish velocity and distance.
ďźA computer which receives signals from the
integrators and changes distance travelled to
position in selected coordinates.
28. RADIO ALTIMETER
ďźMeasures the distance from the aircraft to the
ground
ďźAccomplished by transmitting radio frequency
energy to the ground and receiving the reflected
energy at the aircraft
Modern Day: Pulse Type
ď§Altitude determined by measuring time required
for transmitted pulse to hit ground and return.
ď§Indicating instrument gives true altitude of aircraft
ď§Used during landing to determine decision
whether to continue to land or execute climb-out