airtraffic cnt l radar

8/7/2019 Airtraffic Cnt l Radar

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Air Traffic Control Radar

PRESENTERS:

VAIBHAV.J.SHAH

SMIT.K.SHAH



Over v i ew

� Why we need Air Traffic Control (ATC)

� Notabl e Accid ents

�

Histor y � Id entif y Fri end or Foe (IFF)

� Air Traffic Control Radar Beacon S y st em

(ATCRBS)

� Transpond ers

� Mod e S

� Traffic Collision Av oidanc e S y st em (TCAS)

�

T y pes Of Radar



Notabl e Accid ents

N ew York Cit y, Dec. 16 , 1960

�

Unit ed Airlines DC-8 and a T W A Super Const ellationover N ew York Cit y kill ed 128 peopl e on board and 8 peopl e on t he ground. T he Unit ed flig ht had ex peri enc ed partial nav igation equipment failur e but fail ed to r eport it to t he air traffic controll ers.



N ew York Cit y Dec 16 ,1960



Notabl e Accid ents

C erritos, CA, August 31, 1986

� Aeromex ico DC-9 w it h 64 passeng ers collid ed w it h a

pri v at e C essna aircraft carr y ing a famil y of t hr ee. T he DC-9 crashed into a neig hbor hood and d estroyed18 homes and kill ed 15 peopl e on t he ground. T he accid ent w as blamed on inad equat e radar approac h and d epartur e equipment and proc edur es.



C erritos, CA, August 31, 1986



Histor y Ti meline

� In W orld W ar-I Pilots began taking radios in planes . SoAirlines used radio to transmit weat her infor mation to pilots

� 1921 - Ar my d eployed rotating beacons in a line bet ween

Columbus and Day ton, OH

� 1935 - First air traffic control tower established at t he N ew ark Int ernational Airport in NJ

� W orld W ar II - Americans d eveloped IFF (Id entif y Fri end or Foe), installing transpond ers above Alli ed aircraft

� 1958 - F ed eral Av iation Ag enc y, c harg ed w it h establishing and running an air traffic control sy st em



ATCRBS � S y st em shar es t he same fr equenc y bands as IFF

� A sensor on t he ground sends out an int errogation signal

(1030 MHz) from a rotating ant enna(beacon) to aircraft

fl y ing in its sector

� Aircraft equipped w it h transpond ers r ec ei ve t hese

int errogations and send back a r epl y (1090 MHz)

� T her e ar e t w o pri mar y t y pes of int errogations

± Mod e A int errogations ar e used for plane id entification

infor mation

± Mod e C int errogations ar e used for altitud e infor mation



I mportant Parts Of ATCRBS

1.Pri mar y Sur veillanc e Radar.

2.S econdar y Sur veillanc e Radar.

3.Transpond er.



PRIMARY SURVIELLANCE

RADAR(PSR)� It is t he most prominent component of t he sy st em.

� It is r ef err ed as ³SKIN PAINT RADAR´ because it uses t he basic radar principl es for its operation.

� PSR sends radar energ y and r ec ei ves r efl ect ed

energ y from aircraft and find its position.



IFF (SSR)

� IFF- Id entif y ing Fri end Or Foe

� A ground-based transmitt er , t he int errogator ,

broadcasts a radio signal to t he aircraft

� A transpond er on t he aircraft w ould r ec ei ve and r epl y to t his signal

�Int errogations used ar e ver y specific t y pes of signals w it hin rang e1030 to1090 MHz

� If a plane did not r espond corr ectl y t he sy st em d et er mined t hat t he targ et w as an enemy aircraft



Transpond ers

� Transpond ers ar e mandat ed if aircraft fli esabove 10 ,000 f eet or w it hin 30 mil es of a major airport.

� Transpond er is usuall y mount ed in t he

instrument panel or av ionics rack.



How ever y t hing w orks?

� Pri mar y Sur veillanc e Radar (PSR) transmits radar

energ y whic h is d et ect ed by t he aircraft and it r efl ects radar energ y

� Aircraft r eturn is displayed on t he ATC consol e at a

rang e and bearing w it h aircraft position

� T he S econdar y Sur veillanc e Radar (SSR)transmits a seri es of int errogation pulses r ec ei ved by t he aircraft transpond er

� Transpond er r epli es w it h a diff er ent seri es of pulses t hat gi ves aircraft id entifi er and altitud e

� PSR and SSR ar e sy nc hroniz ed , bot h r eturns w ill

be displayed on t he ATC consol e



Probl ems w it h ATCRBS

� ATCRBS uses a rotating ant enna to continuousl y send out int errogations

� An aircraft can be int errogat ed up to 20 ti mes per sweep

�

Eac h ti me, t he transpond er sends back a separat e r epl y � Causes int erf er enc e and overload in t he 1030/1090 MHz

c hannels

� When int erf er enc e occurs t he ground station r ec ei ves

garbl ed signals� As traffic incr eases, t he number of airplanes at a gi ven

ti me w it hin t he ant enna's int errogation beam w ill incr ease



Mod e S

� In t he 1960's, t he Unit ed Stat es air traffic control (ATC) sy st em w as in disarray .

� Mod e S is now r eplacing ATCRBS in many countri es including US

� Discr et e Addr ess Beacon S y st em (DABS) lat er r enamed Mod e S

� S=S el ect: uses discr et e addr essing toint errogat e just one aircraft

� Is a S econdar y Sur veillanc e Radar (SSR)beacon

� Ground-air-ground data link sy st em



Mod e S Int eroperabilit y

� S everal specific d esign d ecisions t hat wer e influenc ed by int eroperabilit y :

± Fr equenc y - 1030/1090 MHz w as mad e so Mod e S and

ATCRBS could communicat e on t he same c hannel

± Modulation - c hosen partiall y to mini miz e t he eff ects of int erf er enc e due to shar ed fr equenc y c hannels

± Signal For mats - t he Mod e S signal itself had to be d esigned so t hat it w as transpar ent to ex isting transpond ers



Mod e S Ant enna Sit e



Planned I mprovements

� T w o major Pr eplanned Product I mprovementscurr entl y und er w ay

± T ec hnolog y upgrad es from 68020 to 68040

proc essors, curr entl y in k ey sit e t est at Grand Junction, C O

± Traffic Infor mation S er v ic e (TIS), a data link ser v ic e t hat assist g eneral av iation (GA) pilots in v isual ac quisition of surrounding air traffic by d eli vering

automatic traffic ad v isori es to t he pilot , curr entl y ink ey sit e t est at Dull es and Andr ew s AFB



Traffic Collision Av oidanc e S y st em

� Tracks up to 30 aircraft , display s t he 25 hig hest priorit y aircraft

� All commercial aircraft must be equipped w it h TCAS by 1993

� Uses t hr ee separat e sy st ems to plot positions of nearby aircraft mentioned below .

� Dir ectional ant ennae r ec ei ves Mod e S transpond er signals toprov id e a bearing to neig hboring aircraft , accurat e to a f ew d egr ees of bearing.

� Mod e C used to plot t he altitud e of nearby aircraft.

� T he ti ming of t he Mod e S int errogation/r esponse protocol is measur ed tofind t he distanc e of an aircraft.

� S y st em Components Of TCAS



TCAS I

� Gi ves t he pilot r elati ve position and velocit y of all aircraft w it hin a 10-20 mil e rang e

� Has a traffic ad v isor y capacit y whic h prov id es a w arning when an aircraft in t he v icinit y g ets too close

� Does not prov id e instructions on how to maneuver inord er to av oid t he aircraft

� W arns pilot of ot her aircraft w it hin +-8700 f eet of aircraft¶s ow n altitud e



TCAS PROTECTION

VOLUME



TCAS II

� Prov id es pilots w it h airspac e sur veillanc e, intrud er tracking , t hr eat d et ection, and av oidanc e maneuver g enerations

� Det er mines whet her eac h aircraft is cli mbing , d esc ending , or fl y ing straig ht and l evel , and sugg ests anev asi ve maneuver

� E v asi ve maneuvers ar e coordinat ed v ia air-to-air transmissions so t he proposed maneuvers w ill not canc el eac h ot her out

� TCAS II C hang e 7 , soft w ar e c hang es and updat ed algorit hms t hat alt er operating paramet ers



T y pes of Radar

� Alti met er

� Weat her



Alti met er

� Radar transmissions to r efl ect off t he surfac e i mmediat el y below t he aircraft

� Prov id es absolut e r eading of altitud e

� Diff ers from barometric or air data alti met er , whic h commonl y r ef er enc e sea l evel altitud e

� Operat es over a max rang e of 0 ± 5000 f eet

� Auto landing and Militar y Application



How an Alti met er W orks

Fr om Ci v ilian Av ionics S y st ems, Figs 5.27 , 5.28



Weat her

� Radiat es energ y in narrow beam r efl ect ed by clouds

� Beam w idt h of ~3 d eg

� Ant enna may be tilt ed in el ev ation around +-15 d eg from

horizontal , some have automat ed tilt

� Display s ar e t y picall y in color

� Transmitt er operat es at 9.345 GHz

� Av iation Conventions(l evels)



Weat her Radar



Summar y

� Why we need Air Traffic Control (ATC)

� Notabl e Accid ents

� Histor y

� Id entif y Fri end or Foe (IFF)

� Air Traffic Control Radar Beacon S y st em

(ATCRBS)

�Transpond ers

� Mod e S

� Traffic Collision Av oidanc e S y st em (TCAS)

� T y pes Of Radar



� http:// www .tc.faa.gov /its/c md/ v isitors/data/ ACT-300/ mod es.pdf

�

http:// mit.edu/6.933/ www /Fall2000/ mod e-s/ind ex .ht ml

� www .w ikipedia.com

S OURCES



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