Finding the means from one place to a different is named NAVIGATION. Moving of AN craft from one purpose to a different is that the most vital half for any quite mission. Plotting on the paper or on the map a course towards a selected space of the planet , within the passed, wont to be a task assigned to a specialised member of the aircraft's crew such a navigator. Such a task was quite difficult and not continuously correct. Since it relied on the observation , victimisation straightforward maps and geometrical instruments for calculations. Today, aerial navigation has become AN art that nears to the letter. each external Navaids (Navigational Aids) and on-board systems facilitate navigate any craft over thousand of miles with such accuracy that might solely be fanciful a number of decades past.
The Method of Navigation
There ar 3 main ways of air navigation. There are:
1. Pilotage , 2. Dead Reckoning , 3. Radio.
Pilotage or Piloting is that the most typical technique of air navigation. This technique, the pilot keeps on target by following a series of landmarks on the bottom. sometimes before take-off, pilot can creating pre-flight designing , the pilot can attracts a line on the natural philosophy map to point the specified course. Pilot can nots numerous landmarks , like highways , railroad tracks, rivers , bridges . because the pilot flies over every of landmark , pilot can checks it off on the chart or map. If the plane doesn't pass directly over thelandmark , the pilot can apprehend that he has got to correct the course.
Dead Reckoning is that the primary navigation technique utilized in the first days of flying. it's the tactic on that Lindberg relied on his 1st trans-Atlantic flight. A pilot used this technique once flying over giant bodies of water, forest, deserts. It demands a lot of ability and knowledge than pilotage will. it's supported time, distance, and direction solely. The pilot should apprehend the space from one purpose to successive, the magnetic heading to be flown. Pilot works on the pre-flight set up chart , pilot set up a route before. Pilot calculate the time to grasp specifically to succeed in the distination whereas flying at constant speed. In the air, the pilot uses compass to stay the plane heading within the right direction. Dead reckoning isn't continuously a triple-crown technique of navigation owing to dynamical wind direction. it's the basic of VFR flight.
Radio Navigation is employed by most pilots. Pilots will establish from AN natural philosophy chart what station they ought to tune to in an exceedingly specific space. they will then tune their radio navigation instrumentation to a symptom from this station. A needle on the navigation instrumentation tells the pilot wherever they're flying to or from station, on target or not .
see sample of natural philosophy chart , preflight set up chart : click here
Pilots have numerous navigation aids that facilitate them takeoff,fly, and land safely. one amongst the foremost necessary aids may be a series of air route control , operated throughout the planet. Most of the control uses a microwave radar screen to form positive all the planes in its section ar flying in their assigned airways. Airliners carry a special sort of microwave radar receiver and transmitter known as a electrical device. It receives a microwave radar signal from centre and in real time bounces it back. once the signal need to the bottom, it makes the plane show au fait the microwave radar screen.
Pilots have special ways for navigating across oceans. 3 ordinarily used ways are:
1. mechanical phenomenon GuidanceThis system has laptop and alternative special devices that tell pilots wherever ar the plane placed.
2.LORAN Long vary Navigation The plane has instrumentation for receiving special radio signals sent out continuous from transmitter stations. The signals can indicate the plane location
3.GPS international Positioning System. is that the solely system these days able to show your precise position on the planet any time, anywhere, and any weather. The system receiver on the craft can receives the signals from sattelites round the globe.
TERMINOLOGY
ADF Automatic receiving system. AN craft radio navigation that senses and indicates the direction to a Low/Medium Frequency non-directional radio beacon (NDB) ground transmitter.
DME Distance measure instrumentation. Ground and craft instrumentation which give distance data and first serve operational desires of en-route or terminal space navigation.
EAT calculable Approach Time
EFIS Electronic Flight Instrument System , within which multi-function cathode-ray tube displays replace ancient instruments for providing flight, navigation and craft system data, forming a questionable " glass cockpit ".
ETA calculable Time of Arrival
GPS international Positioning System . A navigation system supported the transmission of signals from satellites provided and maintained by the u. s. of America and accessible to civil aviation users.
HDG Heading. The direction within which AN aircraft's nose points on the wing within the horizontal plane, expressed in compass degrees (eg. 000 or 360 is North, 090 is East)
HSI Horizontal state of affairs Indicator. A cockpit navigation show, sometimes a part of a flight-director system, which mixes navigation and heading.
IFR Instrument Flight Rule . prescribed for the operation of craft in instrument meteorologic condition.
ILS airplane landing System . consists of the localizer, the glideslope and marker radio beacons (outer, middle, inner). It provides horizontal and vertical steering for the approach.
INS steering System. It uses gyroscopes and alternative electronic chase systems to sight acceleration and speed, ANd computes an aircraft's position in latitude and line of longitude. Its accuracy, however, declines on long flights. additionally known as office, or mechanical phenomenon system.
KNOT (kt) normal Unit of speed in aviation and marine transportation, such as one marine mile per hour. One knot is up to one.1515 mph., and one marine mile equals to six,080 feet or one.1515 miles. One knot is up to one marine mile per one hour.
LORAN C Long vary Navigation may be a Long-Range low frequency Radio Navigation. Its vary is regarding one,200 nm by day to two,300 nm. by night.
MAGNETIC COURSE Horizontal direction, measured in degrees dextral from the north.
MACH NUMBER quantitative relation of true velocity to the speed of sound. philosopher one is that the speed of sound embarrassed level. Its values is close to 760 mph.
NDB Non-Directional Beacon. A radio frequency steering aid that transmits non-directional signals , superimposed with a Morse symbol ANd received by an aircraft's ADF.
RMI Radio Magnetic Indicator. A navigation aid which mixes DI ,VOR and /or ADF show and can indicate bearings to stations, in conjunction with craft heading.
RNAV space Navigation. A system of radio navigation which allows direct point-to-point off-airways navigation by suggests that of AN on-board laptop making phantom VOR/DME transmitters termed waypoints.
TACAN military science Air Navigation. Combines VOR and DME and employed by military craft solely.System that uses ultrahigh frequency frequencies , providing data regarding the bearing and distance from the bottom station we've tuned into.
TCAS Traffic Alert and Collision dodging System. microwave radar based mostly mobile collision dodging system in operation severally of ground-based instrumentation. TCAS-I generates traffic advisories solely. TCAS-II provides advisories and collision dodging directions within the vertical plane.
TRANSPONDER mobile receiver / transmitter that receives the interrogation signal from the bottom and mechanically replies consistent with mode and code selected . Mode A and B wre used for identification, employing a four digit range allotted by traffic management. Mode C offers automatic altitude readout from AN coding measuring system.
VFR Visual Flight Rules. Rules applicable to flights in visual environmental condition.
VHF terribly High Frequency. oftenness within the 30-300 rate band, used for many civil air to ground communication.
VOR terribly High Frequency omnirange. A radio navigation aid in operation within the 108-118 rate band. A VOR groun station transmits a two- part directional signal through 360 degrees. The aircraft's VOR receiver allows a pilot to spot his radial or bearing From/To the bottom station . VOR is that the most ordinarily used radio navigation aid privately flying.
VORTAC A special VOR which mixes VOR and DME for civil and military used . System provides data regarding the bearing and distance from the bottom station we've tuned into.
VOR (VHF Omni-Range) is that the basic Electronic navigation that in use these days . This VHF Omni-Range navigation technique depends on the bottom based mostly transmitters that emitted signals to VOR receiver. The VOR system operates within the VHF waveband , from 108.0 to 117.95 MHz. The reception of VHF signals may be a line of sight state of affairs . you need to get on the minimum altitude of one thousand feet (AGL) higher than ground level so as to choose up AN Omni signals service vary.
VOR Range
VOR Class= Low Altitude one,000-18,000 feet vary forty marine miles
VOR Class=High Altitude one,000-14,500 feet vary forty marine miles
VOR Class=High Altitude fourteen,500-60,000 feet vary one hundred marine miles
VOR Class=High Altitude eighteen,000-45,000 feet vary one hundred thirty marine miles
OPERATION
The VOR facility at ground base transmits 2 signals at an equivalent time. One signal is constant altogether directions as a reference part. Another signal, it's variable-phase signal and it rotates through 360 degrees, just like the beam from the tower. each signals ar in part once the variable signal passes 360 degrees (reference to magnetic north) and that they ar a hundred and eighty degrees out of part once the rotating signal passes a hundred and eighty degrees The craft instrumentation receives each signals. The receiver can calculate the distinction between the 2 signals, and interprets the result as a radial from the station to pilots on the craft.
RADIALS: the 2 signals from VOR transmitter generate 360 lines like spokes in an exceedingly wheel . every line is named a Radial . VOR navigation instrumentation on the plane can verify that of these 360 radials the plane is on.
VOR INDICATOR:
A : Rotating Course Card is graduated from zero to 360 degrees, that indicates the VOR bearing chosen because the regard to fly by pilot.
B : Omni Bearing Selector or OBS knob , wont to manually rotate the course card to wherever the purpose to fly to.
C : TO-FROM indicator . Triangulum arrow can emphasize once flying to the VOR station. The arrow can purpose DOWN once flying far from the VOR station. A red flag replaces these TO-FROM arrows once the VOR is on the far side reception vary or the station is out.
D : Course Deviation Indicator (CDI). This needle moves left or right indicating the direction to show the craft to come back to course.
DOT : The horizontal dots at center ar represent the craft far from the course . every dot represent two degrees deviate from desired course.
How It Works
The followings ar simply the standard, some craft could also be vary in details . The pilot will set VOR receiver to chose ground station or another word is to pick a radial to outline a magnetic course toward or far from VOR station on receiver. The Radial of the VOR receiver is split into 360 degrees, at the purpose 360 is representing north . once we known as out , we have a tendency to known as in 3 digits like 090 {that suggests that|meaning|which means} on the East and 270 means on the West .
The proper time to tune navigation receivers is whereas the craft is on the bottom as a result of the pilot has got to do the flight planned and familiar wherever to travel. when takeoff, sometimes begin from altutude of one thousand feet minimum higher than ground level, the VOR receiver can get signals from transmitter and therefore the flag can show arrow .
When the craft has gone 0.5 means or near next VOR station and VOR receiver got that signals from next station . The arrow flag can modification from FROM to TO arrow. At now, pilot ought to choose OBS to Radial of next VOR station.
CDI on the indicator shown off center by four dots which suggests that eight degrees off the course, the pilot should correct the heading of craft.
If the craft out of transmitter vary or VOR station not operates, the VOR receiver can show red flag or indication to inform pilot that do not see as a result of CDI needle can reside center all the time.
ADF (Automatic Direction Finder) is that the radio signals within the low to radio frequency band of one hundred ninety kHz. to 1750 kHz. it had been wide used these days. it's the foremost advantage over VOR navigation within the reception isn't restricted to line of sight distance. The ADF signals follow the curvature of the planet. the most of distance is rely on the facility of the beacon. The ADF will receives on each AM station and NDB (Non-Directional Beacon). business AM radio stations broadcast on 540 to 1620 kHz. Non-Directional Beacon operate within the waveband of one hundred ninety to 535 kHz.
ADF parts
ADF Receiver : pilot will tune the station desired and to pick the mode of operation. The signal is received, amplified, and born-again to perceptible voice or Morse transmission and powers the bearing indicator.
Control Box (Digital Readout Type) : most recent craft has this sort of management within the cockpit . during this instrumentation the frequency tuned is displayed as digital readout. ADF mechanically determines bearing to chose station and it on the RMI.
Antenna : The craft accommodates 2 antennas. the 2 antennas ar known as LOOP antenna and SENSE antenna. The ADF receives signals on each loop and sense antennas. The loop antenna in common use these days may be a little flat antenna while not moving elements. inside the antenna ar many coils spaced at numerous angles. The loop antenna sense the direction of the station by the strength of the signal on every coil however cannot verify whether or not the bearing is TO or FROM the station. The sense antenna provides this latter data.
Bearing Indicator : displays the bearing to station relative to the nose of the craft.
Relative Bearing is that the angle shaped by the road drawn through the middle line of the craft and a line drawn from the craft to the station.
Magnetic Bearing is that the angle shaped by a line drawn from craft to the station and a line drawn from the craft to north (Bearing to station).
Magnetic Bearing = Magnetic Heading + Relative Bearing.
TYPE OF ADF INDICATOR
Four forms of ADF indicators ar in use these days. In each case, the needle points to the navigation beacon.Those four sorts are:
Fixed mariner's compass : it's fastened to the face of instrument and can't rotate. zero degree is usually straight up because the nose of craft.
The relationship of the craft to the station is refered to as " bearing to the station " MB or craft to north. this sort of indicator, pilot should calculate for the bearing by formular
MB = metal + MH
Rotatable mariner's compass : The dial face of the instrument is turned by a knob. By rotating the cardboard specified the Magnetic Heading (MH) of the craft is adjusted to be underneath the pointer at the highest of the cardboard.
The bearing to station (MB) is scan directly from the mariner's compass while not calculation and build it straightforward for pilot. Today , they designed mechanically rotate the mariner's compass of the instrument to accept as true with the magnetic heading (MH) of the craft . so MB to station is scan at any time while not manually rotating the mariner's compass on the ADF face.
Single-Needle Radio Magnetic Indicator : Radio Magnetic Indicator is AN instrument that mixes radio and magnetic data to supply continuous heading , bearing , and radial data.
The face of the one needle RMI is comparable to it of the mobile card ADF.
Dual-Needle Radio Magnetic Indicator : the twin needle RMI is comparable to single needle RMI except that it's a second needle. the primary needle indicated a bit like single needle. inthe image , the yellow needle may be a single that indicate the Magnetic Bearing to the NDB station . The second needle is that the inexperienced needle.
The second needle (green) is purpose to VOR station .The dual needle indicator is helpful in find the situation of AN craft.
OPERATION
ADF operate within the low and radio frequency bands. By standardization to NDB station or business AM radio stations. NDB frequency and identification data could also be obtained from natural philosophy charts and field Facility Directory. The ADF has automatic direction seeking qualities that end in the bearing indicator continuously inform to the station to that it's tuned. the best and maybe the foremost common technique of victimisation ADF , is to " home " to the station . Since the ADF pointer continuously points to the station , the pilot will merely head the plane so the pointer is on the zero (zero) degree or nose position once employing a fastened card ADF . The station are going to be directly earlier than the plane. Since there's nearly always some wind at altitude and you'll be granting drif, that means that your heading are going to be completely different from your track. Off track , if the craft is left of track, the pinnacle of the needle can purpose right of the nose. If the craft is true of track , the pinnacle of the needle can purpose left of the nose.
For fastened mariner's compass , if you're not fly orienting and you would like to fly heading at some degrees. you need to use the formular MB = MH + metal to search out out what degree the ADF pointer ought to get on. Today , the fastened card indicator is extremely disappointing for each day use which might still be found on craft panels however not several planes that pilot really uses it as a result of it's easier sort of indicator.
For mobile mariner's compass, it had been an enormous step over the fastened card indicator. The pilot will rotate the mariner's compass with the heading knob to show the craft MH " straight up " . Then the ADF needle can directly indicate the magnetic bearing to the NDB station.
For Single needle Radio Magnetic Indicator , the compasscard may be a directional gyro and it rotates mechanically because the craft turns and supply continuous heading . it's accurately indicates the magnetic heading and therefore the magnetic bearing to the beacon. This instrument may be a " hands off " instrument.
For twin needle Radio Magnetic Indicator, it's provide the pilot data an equivalent because the single needle like craft heading and magnetic bearing to the NDB . The seacond indicator can purpose to VOR station . This facilitate pilot to examine the situation of the craft at that point .
LORAN (Long vary Navigation) the most recent system called LORAN-C .This system are going to be out of print as a result of price not effective. The USA can still operate the LORAN-C system on the far side the antecedently planned December 31, 2000. The termination date is constant to guage the future would like for continuation of the system. User are going to be given cheap notice so they'll have the chance to transfer to various navigation aids. At now we'll talking regarding this technique a bit as a result of they could keep this technique as a make a copy system.
OPERATION LORAN may be a internet work of land based mostly radio transmitters ANd was developed to supply an correct system for long vary navigation. LORAN Stations Operations ar organized into sub-groups of 4 to 6 stations known as " CHAIN ".One station within the Chain is selected the " MASTER " et al. ar known as " SECONDARY " or " SLAVE " Stations.
The theory is to calculate the time between reception of the signals from the MASTER and SLAVE stations, that ar emitted at completely different frequencies , at low or terribly low bands 90kHz - a hundred and ten kHz. in pulse cluster and has power of four hundred - 1600 kilowatts. The master station emits its own signal 1st, once that signals reach the slave station , it emits its own signal when a planned delay. once the master station's signal reaches the craft , its Navigation system counts the time till the slave station's signal arrives. Your position is found because the intersection of the road of 2 LORAN stations.
LORAN UNIT
SIGNAL PROCESSOR
NAVIGATION laptop
CONTROL and show
Signal Processor receives the signals and measures the distinction between the time of arrival of every secondary station pulsegroup and therefore the master station pulse cluster. The time distinction is rely on the situation of the receiver on the craft in respect to the 3 or a lot of transmitters.Each time distinction price is measured to a exactness of regarding zero.1 microseconds.
Navigation laptop converts time distinction values to location corresponding latitude and line of longitude.
management and show
The functions of the LORAN UNIT is:
Preset Position in Latitude-Longitude and/or relative to a destination, waypoint or check purpose.
Bearing and distance to your destination
Ground speed and calculable time enroute.
Course Deviation Indicator.
Storage in memory of airports.add-on programable and updatable info.
Continuous computation of bearing and distances to the closest airports. computation of wind direction and speed.
Add-on like fuel flow analyzers to estimate fuel have to be compelled to reach destination.etc.
GPS (Global Positioning System) is that the solely system these days able to show you wherever your specifically position on the planet at anytime and any atmospheric phenomenon. twenty four satellites ar all orbit round the earth at eleven,000 marine miles or close to twenty,200 kms. higher than the planet. The satellites ar placed into six completely different orbital planes and fifty five degree inclination. they're unendingly monitored by ground stations placed worldwide.
GPS components we will divide GPS system into 3 segments.
SPACE section
USER section
CONTROL section
SPACE section The house section includes a network of satellites . the whole GPS house system includes twenty four satellites, 11,000 marine miles higher than the planet, take twelve hours every to travel round the earth once or one orbit. they're orbit in six completely different planes and fifty five degrees inclination. These positions of satellites, we will receive signals from six of them nearly of the time at any purpose on earth. Satellites ar equipped with terribly precise clocks that keep correct time to inside 3 nanoseconds ( zero.000000003 of a second or 3e-9)
This exactness temporal order is vital as a result of the receiver should verify specifically however long it takes for signals to travel from every GPS satellite to receiver.
Each satellite contains a offer of fuel and tiny servo engines so it is touched in orbit to correct for positioning errors.
Each satellite contains four atomic clocks. These clocks ar correct to a unit of time .
Each satellite emits 2 seperate signals , one for military functions and one for civilian use.
SOME SPECIFICATION OF SATELLITE
Weight 930 kilogram.(in orbit)
Size 5.1 m.
Travel speed four km/sec
Transmit Signals 1575.42 rate and 1227.60 MHz
Receive at 1783.74 MHz
Clocks two caesium and a pair of Rb
Design life seven.5 year (later model BlockIIR ten years)
USER section because the pilot fly , the GPS receiver unendingly caculates the present position and show the right position / heading.The GPS unit hear the satellite's signal and live the time between the satellites transmission and receipt of the signal. By the method of triangulation among the many satellites being received, the unit computes the situation of the GPS receiver. GPS receiver has got to see a minimum of four satellites to work out {a 3|a 3} dimensional position (it will work out position with solely three satellites if apprehend altitude). Not solely latitude and line of longitude , however altitude additionally. There ar various kinds of show among the assorted manufacturer. No frequency standardization is needed , because the frequency of the satellite transmissions ar already familiar by the receiver.
CONTROL section The management section of GPS consist of:
Master management Station ( one station ): The master management station is accountable for overall managment of the remote observance and transmission sites. because the center for support operations , It calculates any position or clock errors for every individual satellite from monitor stations so order the suitable corrective data back to it satellite.
Monitor Stations ( four stations ): every of monitor stations checks the precise altitude , position , speed , and overall of the orbiting of satellites. A station will track up to eleven satellites at a time. This check-up is performed doubly on a daily basis by every station because the satellites go round the earth.
Conclusion:
The principle of GPS is that the measure of distance between the receiver and therefore the satellites. The satellites additionally tell USA specifically wherever they're in their orbit higher than the planet . The receiver is aware of our precise distance from satellite , is aware of the space between satellites. GPS receivers have mathematical technique by laptop to work out specifically wherever the GPS receiver might be placed...
