assignment 1

• DECCA


  Hyperbolic radio navigation system which allowed ships and aircraft to determine their position by receiving radio signals from fixed navigational stations
• DECCA principle of operation

  1. Based on the phase comparison that contains wave transmission from groups or chains of synchronized transmitter from a center controlling master station with three slaves are deployed in a triangle formation

  2. DECCA receives and multiplied the signals from the master and each slave stations that are known by colors green, red and purple lanes, those slaves are are face lock to the master transmission to either reflect or refract the signals back

  3. To enable a perfect landing an aircraft receives signal to determine a location by measuring the phase difference from two or more of the patterns as from the display
• LOREN

  Long range navigation system that allows a receiver to determine its position by listening to low frequency radio signals that are transmitted by fixed land base radio stations
• LOREN principle of operation

  1. Combined two different techniques to provide as signal that was both long-rang

  2. One station remains constant; the primary waves being paired up separately with two other secondary stations

  3. Two station between the primary and the secondary identifies one curve or line

  4. The time taken for a transmission is define by the distance between the start of primary signals and the secondary thus the Doppler effect
• Disadvantages of DECCA navigation system

  • Atmospheric Effects because ionosphere contains ion in the atmosphere, signals coming from satellite will be delayed to the ground station. Conditions of the weather, interference and signal reflections
  • Instrumental errors
  • Sky wave errors or satellite position as in two satellite in close contact
  • Wave signals are not clearly shown during night
• Disadvantages of LOREN navigation system

  • Expense equipment is needed to interpret the signals
  • Cost, Weight and size of electronics has been reduced that is high cost of LORAN receivers and the users cannot afford
• Differences between DECCA and LOREN

  • DECCA uses phase comparison between low frequency signals between 70KHz and 129KHz
  • LOREN combines two radio signals, pulse timing and phase
  • DECCA experiences errors due to factors affecting the signals
  • LOREN had its own errors but it is manageable
  • DECCA does not have any specific techniques
  • LOREN has techniques for modelling
  • DECCA is affordable
  • LOREN is uneconomical