ATC equipment radar principles Flashcards
What does RADAR stand for?
Radio detection and ranging
What is PSR?
Primary surveillance radar, returns horizontal position.
What is SSR?
Secondary surveillance radar, uses a 4 digit squark code to identify a/c and sometimes shows extras like level info depending on mode.
What will weather affect more, long wavelength or short wavelength?
Short
How fast does an SMR spin?
45-60 RPM
What are the 3 SSR modes?
A - Identity
C - Level information
S - Extra information
What is MTI?
Moving target indicator, uses the Doppler effect to tell if something is moving and removes clutter.
What is one problem with MTI?
If an a/c flys at a tangent to the radar it causes tangential fade and the radar may remove it as clutter.
What is an advantage of PSR?
A/c do not need any equipment on board for it to work.
What are 5 disadvantages of PSR?
- Requires a strong signal and correct signal therefore suffers from signal attenuation.
- Shows clutter.
- Provides limited information.
- Distance given is slant range.
What numbers can be used for squark codes?
As it uses 3-bit binary only numbers 0-7 can be used.
How many mode A squark codes are there?
4096
What are the 2 types of SSR codes?
- Discreet codes (Assigned)
- Conspicuity code
What are 5 advantages of SSR?
- Less transmitter power required for similar range.
- No ground or weather clutter.
- Provides aircraft identification.
- Level information if mode C or S.
- Provides use of conspicuity codes.
What are 4 disadvantages of SSR?
- A/c requires a transponder.
- No weather or clutter displayed.
- Label garbling.
- Possible antenna shadowing will mean a/c is not displayed.
What are 5 advantages of mode S?
- More accurate.
- Provides controller / pilot information via uplink and downlink capabilities.
- Allows the a/c to fly in class A and C airspace.
- Almost 17 million aircraft addresses.
- More accurate info for (STCA and TCAS 2)
What is shown by elementary mode S?
- Automatic Identification
- More accurate level info (25ft)
- Flight status (On ground or in flight)
What is shown by enhanced mode S?
- Magnetic heading
- Speed (IAS and Mach number)
- Roll angle
- Rate of turn
- Climb rate
- Ground speed
- Selected flight level
What is ADS?
Automatic dependent surveillance is a surveillance technique where a/c automatically report Nav data via data link including a/c identification.
What are the two ADS versions?
ADS-B and ADS-C
What is ADS-B
Broadcast, Broadcasts data out to everyone.
What is ADS-C
Contract, only ANSPs with a contract receive the data. Only used in low traffic areas.
What is MLAT?
Multilateration system, a group of equipment configured to provide position derived from the SSR.
