Ra dio D etection A nd R anging (RADAR)

1. Radio Detection And Ranging(RADAR)

2. Exercises • Describe the basic principles of RADAR. • What are the bands of frequencies for ATC Radars? • What are the disadvantages of Primary Surveillance Radar(PSR)? • Describe the characteristics of Secondary Surveillance Radar (SSR). • What are the differences between PSR & SSR.

3. 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, motor vehicles, weather formations & obstacles (mountain, trees, etc.)

4. Radar Applications/Uses • Radar uses include: • Air traffic control • Weather Forecasting, • Measuring ocean surface waves • Police detection of speeding traffic • Satellite

5. What information RADAR can give?? Target range (distance) Target height (altitude) Target speed Target identity Target features (imaging) Target size

6. How 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-based 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.

7. En-Route Radar Display

8. 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

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

10. 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.

11. ATC Radars • Surface Movement Radar (SMR): Short-range ground radar • Terminal Approach Radar (TAR): Long-range ground radar • Primary Surveillance Radar (SSR) • Secondary Surveillance Radar (SSR)

12. Surface Movement Radar (SMR)

13. 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. SMR Radar Display inside ATC tower control room

14. Terminal Approach Radar (TAR)

15. Terminal Approach Radar (TAR) • A high definition radio detection device which provides information on identification, air speed, direction and altitude of aircraft to assist air traffic controllers to track the position of aircraft in the air within the vicinity of the airport.

16. Radar Display

17. Radar Display What appear on radar display? Aircraft Identity. Altitude Speed Direction Example MH092 FL280 585 Meaning: Flight Malaysian 092 cruising at 28’000ft with speed of 585knots

18. Radar Frequencies

20. Radar Frequency Band

21. Frequency Bands for ATC Radars? • L-Band Radar (En-Route 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) • S-Band Radar (Terminal Approach Radar -TAR): • 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 50-60 NM (≈100 km). • K- and Ka- Band Radars (Surface Movement Radar) • This frequency bands (18-40 GHz) provide short range, very high resolution data.

22. Terminal Approach Radar (TAR)

23. Primary Surveillance Radar (PSR)

24. Primary Surveillance Radar (PSR) • First ATC radar developed. • 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

25. Disadvantages of Primary Surveillance Radar (PSR) • 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).

26. Secondary Surveillance Radar (SSR)

27. Characteristics of Secondary Surveillance Radar (SSR) • SSR is a much more accurate that complements the basic PSR. • SSR is smaller than PSR, it can be installed either singly or co-mounted with PSR. • SSR relies on a piece of equipment on the aircraft known as a 'transponder'. • The transponder is a radio receiver and transmitter which receives on one frequency (1030 MHz) and transmits on another (1090 MHz). • SSR will detect the identification of the aircraft, the height of aircraft, speed and direction of flight. • These information are transmitted back by the Aircraft’s Transponder on the 1030 MHz back to the ground SSR’s Antennae

28. Advantages of Secondary Surveillance Radar SSR • First, reply signal is much stronger when received at the ground, thus giving the possibility of much greater range. • Second, low power required to radiate the signals, thus reduce the cost. • Third, provides more information: aircraft’s identity, altitude & speed. • Fourth, SSR gives a clearer display because there is no weather or ground return. • Fifth, It is easier to identify aircraft on SSR.

29. Weather Radar

30. Weather Radars • Used for: • Weather detection • Windshear and turbulence detection

31. Weather radar to detect, locate, and measure the amount of precipitation within or falling from clouds

32. Precipitation • Precipitation refers to rain, snow, or hail that falls on the ground.

33. Can weather radar in an aircraft be used for navigation?

34. Weather Radars • A weather radar is used to • To locate precipitation • To calculate its motion, • To estimate its type (rain, snow or hail) • To forecast its future position and intensity. • Thus, only precipitation data will be displayed on the Weather Radar Display. • This weather data could be used by pilot for avoiding the bad weather such as thunderstorms. • Therefore weather radar cannot be used as for navigation.