intro_to_aviation_block_6_20180401181951 Flashcards
What is the history of radar
- been in the experimental stage prior to the second world war. once the war broke out Great Britain perfected then used radar to detect and identify both freindly and enemy aircraft- civilian applications started after the war- Both primary and secondary use of radar is used in canada today- Radar stands for Radio Detection and ranging
What is primary surveillance radar (PSR)
- primary radio works on the principle of transmitting a high energy radio signal through the antenna and waiting for some of that energy to bounce back- Primary surveillance radar (PSR) is used as a back up in cases where an airplanes transponder is not working. Busier airports will use PSR us certain situations because it offers some advatages
What are the components of radar sight
- Antenna (transmits and receives) - transmitter (not on constantly)- receiver (on for a very short amount of time aswell)- synchronizer (generate the timing signals that are essential to the accuracy of the system)- processor (processes the information)- display (displays it for controller)
What is Azimuth
- the direction from the antenna to a target - the radar determines the azimuth of the target by using encoders that are placed around the antenna- there are several of these encoders for every degree- as the antenna rotates, these encoders provide a series of pulses that track the antennas position
What is range (Distance)
- the other piece of information acquired is the distance that the target is from the antenna.- One micro second is one millionth of a second, and it takes 12.36 micro seconds for the RADAR signal to go from one radar nautical mile. A timer measures the elapsed time from when the radar pulse was sent until it receives a replay and converts this to distance- With these to pieces of information the target can be placed on the indicator module (radar screen) at the azimuth and distance where it was detected
What is slant range
- the range determined by a radar system is known as slant range, is the true range from the antenna to the aircraft and does not represent distance across the ground- the higher the aircraft and the closer it is to the antenna, the greater the error
What is target resolution
- resolution is where you have two aircraft that are very close to each other but still have separate and distant targets . there are two types of resolution. Range and Azimuth
What is range resolution
- the minimum longitudinal distance that can exist between two aircraft n the same azimuth that will allow the two to bu shown as separate and distinct targets on the screen. If the aircraft were any closer together there would be no range resolution and would show up as one target
What is Azimuth resolution
- is the minimum difference in azimuth (lateral spacing) that can exist between two aircraft at the same range hat will allow the two to be shown as separate and distinct targets on the screen. If the aircraft were any closer together there would be no azimuth resolution and would show up as one target.
What is the affecting factors of PSR
- Holes (areas where the signal is weaker and doesn’t reflect back)- weather - clutter (2 much stuff like hills trees geese buildings)- RADAR horizon (This is line of sight so energy bends with the curve and detects objects beyond the horizon, this is called inversion)- tangential velocity ( when a moving detector unit cancels out objects like a hovering helicopter, this is preventable by telling the heli to change heading)
what are the two ways to jam PSR
mechanical and electronic
explain the mechanical way to jam PSR
- CHAFF is tips of metal foil which are dropped from aircraft and reflect RADAR signals. CHAFF is usually dropped from aircraft in large quantities. This will only affect primary radar and not secondary radar.
What are the ways chaff is shot out
- Stream - to cover a specific area. 2. Burst - usually to confuse missiles, fighters or anti-aircraft guns using RADAR to track the target. 3. Random - to cause confusion.
Explain the electronic way to jam PSR
- These can either blank out the screen or appear as a strobe on a particular azimuth. - If electronic jamming poses an actual or potential hazard, ATC may request the jamming aircraft to stop by transmitting a “STOP BUZZER” message on guard, 243.0 MHz, identifying the ATC unit and the RADAR band or frequency. All Canadian ATC RADAR operates on the “L” band around 1 GHz.
what is SSR RO
Secondary Surveillance radar (SSR)- Most widley used radar system in canada - doesn’t rely on reflected radio energy as with PSR- a ground station interrogates an airborne station (Transponder) on board the aircraft- the transponder answers to the interogation. The distance and azimuth is determined - one advantage is you can include some data on the response The modes that ATC uses are 3/A and 3/C, with limited use of mode S
what are the steps of SSR RO
- The Interrogator transmits a series of pulses. It sends different types of pulses to acquire different information, as we will learn shortly. In many systems, an aircraft will receive about 8 interrogations every time the RADAR beam hits the aircraft.2. It transmits on a frequency of 1030 MHz but receives on a frequency of 1090 MHz. It transmits an interrogation signal to be received by any aircraft in range. The SSR antenna is synchronized with the PSR or can be mounted by itself if there is no primary antenna. It rotates at the same speed as a primary antenna, determining azimuth and distance in the same way as PSR. 3. The synchronizer works in the same manner as with PSR. It controls the function of the antenna and switches rapidly between receiving and sending modes. 4. Airborne equipment consists of a collocated receiver and transmitter known as a transponder. receives the interrogation on a frequency of 1030 MHz which triggers the transmitter to send a reply on a frequency of 1090 MHz.5. The receiver captures the data from the aircraft’s interrogator and performs basic error checking functionality. The receiver also decodes the information and puts it into a format that the processor can use6. A transponder code assigned to an aircraft is four digits long. There is a possibility of eight numbers for each digit. This converts to a possible 4096 different codes that can be selected on the transponder. Only the numbers from 0 to 7 are used in transponder codes, numbers 8 and 9 are not used. The processor interprets this and references it against the flight plan database (RDPS) to provide a positive ident for the aircraft
Who pushes the IDENT button
the pilot
what are the advantages of SSR
Greatly improved and expanded RADAR coverage for transponder equipped aircraft (not relying on reflected energy). •Facilitates identification of aircraft - eliminates the necessity for identification turns or other cumbersome methods of identification. •Facilitates detection of lost aircraft, or aircraft experiencing an emergency, communication failure or hi-jack. •Targets can still be tracked through areas of weather. •Elimination of clutter from weather or permanent echoes. •Automatic transmission of current altitude information. •Reduces communication workload (identification and altitude features). •SSR gives RAMP the capability of displaying information (data tag) on a given flight on the indicator module (RADAR screen). •SSR is less expensive to install and maintain than PSR.
So why use PSR
Not all aircraft have transpondersand weather and other possible hazards to flight cannot be seen using SSR
What is the situation display
- this display combines the input of PSR and SSR system to provide a representation of an aircraft on the display.- The display provides a wide array of information and a comprehensive set of controls to enable a controller to customize the view of his/her needs. his segment will look at some of the basic elements of the display and information provided
Situation display RO
The situation display will provide information that allows a controller to determine how the target was obtained (PSR and SSR) and what the status of the target is in terms of its signal quality or identification. The Present Position Symbol (PPS) you see here are the basic set of symbols that you will use
what does correlated meanr
means the computer can match the target with a specific flight plan. This enables the display to provide flight specific information not available for uncorrelated aircraft
what does poor signal mean
means the return is weak
what does coasting mean
ndicates the computer is no longer receiving the transponder returns and is estimating the aircraft position
What does indent mean
That target changes from yellow target to a white target and blinks
What does special mean
this symbol is reserved for aircraft that are experiencing unusual circumstances.
Corrilated vs uncorrelated RO
- as the radar searches the sky for aircraft, it also reaches a system that stores flight plan information called NFDPS for flight plans that have been assigned a transponder code that matches the one in the sky. In this example the secondary radar is detecting a transponder code of 6013. It searches and finds that there is a flight plan for JZA8789 with the same code and then takes that information and places it with the target on the RADAR screen. The target is said to be correlated.- If the system does not find a flight plan to match the target it is said to be uncorrelated and will remain with the transponder code showeing
What dose the data tag have on it
- Aircraft Ident (ACID)- Altitude- Ground speed- which controller is controlling the aircraft- weight category- if the aircraft is being transferred to another controller- history trail - vertical movement indicator (VMI) - an arrow showing climbing or descent- special condition code
