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Navigation Aids: GPS - QT

Updated: Apr 20, 2021

Lesson Quicktakes cover the items that should be memorized from each of the wifiCFI Lessons. They do not cover all of the lesson details in-depth.


THE NUMBERS:

  • 24 satellites.

  • 6 orbital planes.


GPS RELAY INFORMATION:

  • ID.

  • Position.

  • Time Code.


CALCULATING POSITIONS:

  • 3 satellites needed to receive 2D position (LAT/LONG).

  • 4 satellites needed to receive 3D position (LAT/LONG and Altitude).

  • 5 satellites needed for RAIM.

  • 6 satellites needed for FDE.


RAIM

Receiver Autonomous Integrity Monitoring.


FDE

Fault Detection and Exclusion.


GPS SENSITIVITY MODES:

  • En-Route:

  • More than 30nm from departure or destination.

  • Sensitivity = 2nm.

  • Terminal:

  • Within 30nm of departure or destination.

  • Sensitivity = 1nm.

  • Approach:

  • Within 2nm of Final Approach Fix (FAF).

  • Sensitivity = 0.3nm.


WAAS

Wide Area Augmentation System.


LAAS

Local Area Augmentation System.

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