Definition
A condition in which the GPS receiver detects that the position information it is providing may not be trustworthy because one or more satellite signals have failed an internal validity check. When an integrity anomaly is detected, the receiver alerts the pilot rather than continuing to display position data that could be inaccurate.
Plain English
The GPS has noticed something wrong with its own data and is warning you that the position it is showing may not be reliable.
Context Anchor
Seen in instrument flying discussions of GPS reliability, especially when deciding whether GPS guidance can be used for navigation or an approach.
Derivation
Integrity comes from the Latin integritas, meaning 'wholeness' or 'soundness.' Anomaly comes from the Greek anomalos, meaning 'uneven' or 'not normal.' Together the phrase means 'a break in the soundness' of the data — something has gone wrong with the trustworthiness of the signal.
Why Pilots Care
An undetected integrity anomaly could allow a pilot to continue using faulty position data during instrument flight, leading to navigation errors or approach deviations.
Analogy
It is like a scale that may be showing the wrong weight and may also fail to warn you that it is wrong. The problem is not just the number shown; it is whether you can trust the number.
Intuition Check
Do not read “integrity” here as honesty or character. Here it means whether the GPS information is reliable enough to use, and whether the system can warn you if it is not.
Example Sentence 1
During the GPS approach, the receiver flagged an integrity anomaly, so the pilot executed the missed approach and requested vectors to the ILS.
Example Sentence 2
During preflight checks the system flagged a potential integrity anomaly, so the pilot selected an alternate navigation source.