Ground-based navigation (identification, orientation, course determination, equipment, ...
Ground-based navigation (identification, orientation, course determination, equipment, tests, regulations, interference, appropriate use of navigation data, and signal integrity).
Bottom line
A VOR station can be positively identified by its Morse code identification or by a recorded voice identification that states the station name followed by "VOR." The GPS receiver verifies the integrity (usability) of the signals received from the GPS constellation through receiver autonomous integrity monitoring (RAIM) to determine if a satellite is providing corrupted information. Pilots encountering navigation error events should transition to another source of navigation and request amended clearances from ATC as necessary.
Key numbers
| Number | What it means |
|---|---|
| 5 satellites in view, or 4 satellites with baro-aiding, to detect an integrity anomaly | RAIM detect |
| 6 satellites in view, or 5 with baro-aiding, to isolate and remove the corrupt satellite signal | RAIM isolate |
| 4 satellites minimum for an accurate three-dimensional position | GPS position |
FAA references
- PHAK ch. 16 (p. 16-23) — FAA-H-8083-25C (2023)
- PHAK ch. 16 (p. 16-31) — FAA-H-8083-25C (2023)
- AIM 1-1-13 (User Reports Requested on NAVAID Outages) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
- AIM 1-1-19 (Ground Based Augmentation System (GBAS) Landing System (GLS)) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
- AIM 1-2-4 (Recognizing, Mitigating, and Adapting to GPS Jamming and/or Spoofing) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
Build understanding you can use
Unlock the full lesson and continue studying this element.
- Full teaching sections: What it is; Key points; Rules and numbers; How it is done
- Check your understanding with answers you can reveal
- Common mistakes paired with the FAA facts that correct them