Lecture 7a: Radio Detection And Ranging (RADAR)

Home Previous Next Help What is RADAR RADAR is stand for Radio Detection And Ranging. Radar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft &ships.

Home Previous Next Help Radar Frequencies Radar operates on UHF and SHF - Super High Frequency (1 GHz - 30 GHz) Why RADAR systems are in a UHF& SHF bands ????

Home Previous Next Help Radar Frequencies RADAR systems are in SHF bands because: a)These frequencies are free from disturbance. b)Higher frequency, shorter wavelength, RADAR used more effective.(shorter wavelengths are reflected more efficiently.)

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Home Previous Next Help Radar Frequency Bands L-Band Radar –This frequency band (1 to 2 GHz) is preferred for the operation of long-range air-surveillance radars out to 250 NM (≈400 km). Used by En Route Surveillance Radar-RSR S-Band Radar –This frequency band (2 to 4 GHz) are used near airports to detect and display the position of aircraft in the terminal area with a medium range up to NM (≈100 km). Used by Terminal Area Radar – TAR K- and Ka- Band Radars –This frequency bands (18-40 GHz) provide short range, very high resolution data. Used by Surface Movement Radar-SMR

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Home Previous Next Help RADAR Applications RADAR has a wide range applications including 1.Ground RADAR : extensively used by ATC to separate aircrafts. 1.Primary RADAR: to track the progress of aircraft. 2.Secondary RADAR: similar like primary radar but secondary radar can provide much more information about the target (aircraft) 2.Airborne Weather RADAR: used by pilots. It provide pilots with information regarding weather ahead.

Home Previous Next Help En-Route Radar Display

Home Previous Next Help 1. GROUND RADAR

Home Previous Next Help Ground radar Ground radar is typically used to fix an aircrafts position which allows ATC to separate aircraft and guide the pilot. There are types types of ground radar which are A) PRIMARY RADAR B) SECONDARY RADAR

Home Previous Next Help A) Primary RADAR Primary RADAR is used to track the progress of aircraft Three Primary RADAR systems used by ATC include 1.En-Route Surveillance Radar (RSR) 2.Terminal Area Radar (TAR) 3.Surface Movement Radar (SMR)

Home Previous Next Help a) En-Route Surveillance Radar (RSR) En-Route Surveillance Radars (RSR) are long range radars which the signal goes to 200 to 300 NM. It used L-band frequencies (1 to 2 GHZ) It used for airway surveillance to provide range and bearing of aircraft. **Surveillance: close observation, especially of a suspected spy or criminal.

Home Previous Next Help b) Terminal Area Radar (TAR) These are medium range radars, up to 75NM. It used S-Band frequencies (2 to 4GHz) It is used as an approach aid and for controlling aircraft traffic close to airport area. Normally used in conjunction with Secondary Radar. **Secondary radar provide additional information such as identification, air speed, direction and altitude of aircraft to assist ATC to track the position of aircraft.

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Home Previous Next Help c) Surface Movement Radar (SMR) SMR is one type of Airport Surface Detection Equipment (ASDE). SMR installed at airport (at top of ATC tower building) to provide a very accurate radar display in all weathers and conditions of visibility. (K & Ka-Band frequencies Ghz) SMR radar display can show all of airfield infrastructure including aircraft movements on runway, taxiway and apron. It is designed to provide clear display of all aircraft on runway or taxiway so that ATC can ensure runway are clear for take-off/landing and also guide aircraft to apron in order.

Home Previous Next Help c) Surface Movement Radar (SMR)

Home Previous Next Help c) Surface Movement Radar (SMR) The surface movement radar (SMR) allows the Air Traffic Controller to 'see' in real time the aircraft and vehicles movements into the airport control area. Surface movement radar can improve both safety and efficiency of airport traffic by providing the ground controller with a clear picture of the areas or under poor visibility conditions.

Home Previous Next Help How Primary Radar Works

Home Previous Next Help How Primary Radar Works A radar system (ground-based) has a transmitter that emits radio waves or microwaves signal. The signal hit airplane and reflect back. Ground radar picks up reflected signal during a break between transmissions. The time taken for the reflected signal to return back enables a computer calculate how far the object is (range). The aircraft data then sent and shown on a Radar Display monitor by ATC Thus, the ATC could know the position of aircraft.

Home Previous Next Help Most conventional aircraft have a rounded shape. This shape creates a very efficient radar reflector. Means that no matter where the radar signal hits the plane, some of the signal gets reflected back

Home Previous Next Help However, some military aircraft are designed and constructed to be non-reflective - the so-called “stealth aircraft”. B-2 Spirit stealth bomber of the U.S Air Force An F-117 Nighthawk stealth strike aircraft F-22 Raptor

Home Previous Next Help A stealth aircraft is made up of completely flat surfaces and very sharp edges. When a radar signal hits a stealth plane, the signal reflects away at an angle. Surfaces on a stealth aircraft also can absorb radar energy as well. So, this aircraft become invisible.

Home Previous Next Help Advantages of Primary Radar The advantage PSR is that it operates totally independently of the target aircraft. Means that no action from the aircraft is required for it to provide a radar return. Only provide range & direction information Primary Radar

Home Previous Next Help Disadvantages of Primary Radar First, transmitted signal is limited by ‘line of sight’, thus signal can be interrupted by buildings, hills & mountains. Second, more power must be radiated to ensure returns from the target. Third, because of the small amount of energy returned at the receiver, reflected signals may be easily disrupted. This may cause the displayed target to 'fade‘ (not clear).

Home Previous Next Help Question Bank 1.Radar & It frequencies a)Define RADAR and give reason why it operates in SHF (Super High Frequency). (6M) b)In details, describe L-Band, S-Band, K & Ka Band Radars. (9M) 2.Primary Radar a)Describe RADAR and its application (3M) b)Describe the three types of Primary Radar used by ATC. (12M) 3.Primary Radar a)Explain how primary radar works & give reason why ‘Stealth’ aircraft can be invisible (9M) b)Describe advantages & disadvantages of primary radar (6M)

Home Previous Next Help Group Presentation Group 1: DME-Distance Measuring Equipment (Faiz,Syeikh,Rubesha,Vijendran,Zarul) Group 2: TCAS-Traffic Collision Avoidance System (Yasser, Padhma, Fairie, Azlina, Girish) Group 3: GPWS-Ground Proximity Warning System (Syedi, Aziz, Nantha, Khaliq, Zul Fiqrie, Shafiq) Group 4: ALS-Approach Lighting System (Bibiana,Fakhrul,Choy, Kingsley, Syahirul)