This document discusses several types of radar systems used in aviation. It describes how ATC radar works using UHF to monitor aircraft positions and allow air traffic controllers to direct pilots. It also explains weather radar systems that allow pilots to detect storms and avoid hazardous conditions. Different radar frequencies like C-band and X-band are discussed as well as other systems like radar altimeters, GPWS, and Stormscope that provide additional safety functions.

1. Avionics Systems Day 5
Section 2

2. RADAR
 RAdio Detection And Ranging
 Ground based
 ATC
 Aircraft based
 Weather radar
 Radio altimeter

3. RADAR
 Radar operates on the “Pulse Echo
principle”
 A short pulse of radio energy is transmitted
 Receiver waits for reflected energy

4. ATC Radar
 Aircraft separation under IFR conditions
 UHF
 Controllers watch aircraft on screens and
give pilots instructions on where to fly

6. Aircraft Radar
 Severe weather avoidance
 Thunderstorms
 Allows pilots to continue flying while
avoiding storm cells

8. Aircraft Radar
 Clouds are invisible to radar, however
ice, rain, & hail will reflect the energy
 Size & intensity of moisture & radar type
will effect the image displayed

10. Aircraft Radar
 Be careful when operating radar on
ground
 Microwaves can be dangerous
 Point into sky
 Outside

11. C-BAND 5400 MHz
 Used primarily by airline operations
 Can see through clouds better
 Less reflective off of small cells to reveal
larger cells behind

12. X-BAND 9333 MHz
 Used by general aviation
 Greater resolution
 Will reflect off of smaller cells with greater
resolution but will not see behind cells

13. Stormscope
 A lower cost storm detection system
 Uses an AM directional receiver that
detects lightning discharge
 NOT RADAR

14. Stormscope
 Uses a loop antenna & a microprocessor
to determine the direction to a lightning
strike / storm cell
 Displays lightning strike data on a screen

16. Radar Altimeter
 A.K.A. Radio Altimeter or simply RAD ALT
 A single target radar system used to
indicate aircraft AGL (Above Ground
Level) altitude
 4300 MHz
 Measures the time it takes for a radio
pulse to go to the ground and return

18. Radar Altimeter
 Antenna is located on belly of aircraft
 Usually measures no higher than 5000 ft
 Usually used during landing

19. GPWS
 Ground Proximity Warning System
 Warns pilot of excessively low altitude
 “PULL UP!” “PULL UP!”

20. GPWS
 Computer monitors several different
systems
 Radar Altimeter
 Air data computer
 Landing gear
 Flaps
 Glideslope
 Primary component is the computer

21. GPWS
 Warnings are activated during flight
 Terrain avoidance (gear & flaps up)
 During landing
 Excessive rate of descent
 Below glideslope
 Below minimums
 Enhanced GPWS systems incorporate a
worldwide terrain database & GPS
inputs