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Flashcards

8. Radar

Ella Davies RNAV English 94 cards

Cards in this deck (94)

  1. 1what is the basic principle of radarecho principle
    time of propagation from transmission to returning echo gives the range
  2. 2define pulse lengthduration of the pulse (micro seconds)
  3. 3define pulse widthdistance of the (m)
  4. 4PRIpulse recurrence interval
  5. 5define PRItime separating two pulse radiations
    beginning of one to beginning of another
  6. 6define PRFnumber of pulses transmitted in one second
  7. 7what is the formula involving the PRF and PRIPRF = 1/PRI
  8. 8why does a radar have a maximum unambiguous rangebecause if the time of propagation of the echo is longer than the PRI, the receiver cannot calculate the correct range
  9. 9what is the formula for the maximum theoretical rangeRange (km) = 300 000/ PRF x 2
  10. 10how does a radar have a minimum rangeif the time of propagation of the echo is shorter than the pulse length, the receiver cannot hear/catch the echo
  11. 11what is the minimum theoretical rangerange(minimum) = 0.5 pulse width
  12. 12how many meters can the radar travel in one microsecond300 m
  13. 13what is the relationship between the PRI and PRFThey are inversely proportional
  14. 14what does RADAR stand forradio detection and ranging
  15. 15what is important to remember about the RADAR than can cause limitationsyou cannot transmit and receive at the same time
  16. 16what information can the ATC read on the RADAR displaybearing
    range
  17. 17what can you say about the antenna/beam and display screen for ATCrotating beam is synchronised with the display of the ATC
  18. 18what is the radar system comprised ofmaster time control
    display
    transmitter
    receiver
    duplex antenna
  19. 19what is the formula of the Beam widthBW = 70 x wavelength / antenna diameter
  20. 20what kind of frequency is associated with short rangehigher frequency
  21. 21what PRF value is associated with short rangea higher PRF
  22. 22what is the pulse length associated with short range radara smaller pulse length
  23. 23what is the beam width associated with short rangesmall beam width
  24. 24what is the RPM associated with short rangehigh RPM
  25. 25wha frequency is associated with long rangelow frequency
  26. 26what PRF is associated with long rangesmall PRF
  27. 27what pulse length is associated with long rangeslonger pulse length
  28. 28what beam width is associated with long rangesbigger beam width
  29. 29what RPM is associated with long rangeslower RPM
  30. 30what is the benefit of lower frequenciesbetter cloud penetration
  31. 31what is the benefit of a higher PRFbetter accuracy
  32. 32what is the benefit of a shorter pulse lengthbetter accuracy
  33. 33what is the benefit of a smaller beam widthbetter accuracy
  34. 34what is the benefit of a faster RPMhigher rate of refresh
  35. 35define a resolution cellvolume of space occupied by a pulse
  36. 36what can be said about the radar resolution depthit is constant regardless of distance from the transmitter
  37. 37what does radar resolution depth depend onpulse length
  38. 38define resolutionability of the radar to detect and display close targets separately
  39. 39define azimuth resolutionthe ability of a radar to separate targets that are at the same range but on slightly different bearings
  40. 40what does beam width depend onaerial characteristics and transmission wavelength
  41. 41what happens to the diameter of the beam with an increase in rangeit increases
  42. 42what will happen if two aircraft are inside the same resolution cellthe receiver will only catch one pulse echoes back and only ONE plot will be displayed
  43. 43how do you decrease the beam widthyou must increase the size of the antenna
  44. 44what are the ideal characterisitcs of a radar beam in regards to vertical and horizontal extentyou want to have a narrow horizontal beam and a wide vertical beam
  45. 45what is the relationship between transmitter power and rangerange^4 = power
  46. 46define clutteran unwanted error travelling back to the reciever and displayed on the ATC scope
  47. 47what are the two different types of clutter1. ground clutter
    2. rain clutter
  48. 48how can rain clutter be reducedby using an antenna that is made for the reversed circular polarisation
    meaning that it will not detect any circular polarisation that may come from a rain drop, but will accept the irregular shape reflected from an AC
  49. 49how do we reduce ground clutterby using an MTI
  50. 50MTImoving target indicator
  51. 51what is the purpose of the MTITo eliminate non-moving/static targets
  52. 52what speed can be measuredradial speed
  53. 53how is radial speed measuredby the doppler effect
  54. 54what type of radar is used en-route ATClong range surveillance radar
  55. 55what is the basic idea, relating to rotationyou can have a much slower rotation as the separation between aircraft is very large, and in each rotation the AC may move 0.5nm
  56. 56what radar is used from cruise to approachthe Terminal Surveillance Radar
  57. 57what can be said about the terminal surveillance radarthe separation between aircraft is much smaller and therefore and therefore it needs to be refreshed more often, and therefore has a higher speed of rotation
  58. 58what is the range associated with the terminal surveillance radarmedium range
  59. 59what radar is used for guidance to approachApproach surveillance radar
    Precision approach radar
  60. 60what does the precision approach radar providea glidepath to follow
  61. 61how many antennas are associated with the precision approach/ approach surveillance radar2 antennas
  62. 62who does surveillance radar approaches of any kindthe military
    civil only if no MLS/ILS is available
  63. 63what radar is used for aircraft taxi and vehicle movementsurface movement radar
  64. 64what can the surface movement radar be used forto distinguish size and type of aircraft
  65. 65what does a surface movement radar needa very high rate of refresh
  66. 66what is the rate of refresh of the surface movement radar60-120 rounds per minute
  67. 67what can be said about the accuracy of the surface movement radarvery accurate detections
  68. 68what can be said about the range of the surface movement radarvery short range
  69. 69what can be said about the value of the PRFit is very high
  70. 70what can the quality of detection be altered by-material
    -shape
    -aspect
  71. 71list the materials best to worstmetal
    composites
    wood
  72. 72what shapes give the best reflectionround parts reflect more, and large and bulky
  73. 73how does the aspect impact the detection qualitywhen you are climbing you have a bigger surface area being detected
  74. 74what is the relationship between reflection and the visible surface Area,reflection is directly proportional to the surface area exposed
  75. 75what are the three components of the resolution cell1. resolution depth
    2. radar resolution height and width
    3. range resolution
  76. 76what is the equation for radar coverage distanceRCD = 150 x pulse length (micro seconds)
  77. 77what is the attenuation when the wavelength is more than 10 cmnegligible
  78. 78what is the attenuation when the wavelength is 3cmsignificant in rain or CB droplets
  79. 79what is the attenuation when the wavelength is 1 cmincreasing in all cloud types
  80. 80what is the attenuation when the wavelength is less than 0.5 cmmay be caused by oxygen or water vapour ect
  81. 81when does the radar become unuseableif the wavelength drops below 0.5 cm
  82. 82what is the problem associated with the MTIit can be hard to detect slow moving targets (helicopters)
  83. 83what are the main advantages of the radarno ac system is needed
    excellent resolution
    guidance and regulation ATC (600m)
  84. 84what are the main disadvantages of the radarbad rainfall detection
    no ident
    no altitude data
    for altitude data AC would need an interpret and reply system
  85. 85ASRaerodrome surveillance radar
  86. 86PARprecision approach Radar
  87. 87what is the main difference between the twoASR only provides information in the horizontal plane, as it gives no height information
  88. 88how far from the threshold are SRA usually terminated2nm out
  89. 89what does the PAR have2 independant radars
  90. 90how much does the azimuth element scan10 ˚ either side of the extended centre line
  91. 91how much does the elevation element scan7˚
    from 1˚ below to 6˚ above the glidepath
  92. 92what can you say about the Obstacle clearance and decision height of the PAR compared to the SRAit will be much lower, as it is far more accurate
  93. 93ADSautomatic dependant surveillance
  94. 94what does the ADS use to give positionGNSS
    IRS
    FMS

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RNAV Flashcards on 8. Radar, created by Ella Davies on 15/05/2018.
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Ella Davies
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