Definition
In GPS navigation, a condition in which a satellite signal arrives at the receiver by more than one path or is otherwise distorted, so the receiver cannot determine a single, reliable distance to the satellite. This typically results from multipath reflections (signals bouncing off terrain, water, or buildings) or from weak or interfered-with signals, and it degrades position accuracy.
Plain English
The GPS receiver is getting a signal it can't fully trust because the signal has been bounced around or scrambled, so it isn't sure exactly how far away the satellite really is.
Context Anchor
Seen in GPS discussions about signal quality, position accuracy, and why a displayed GPS position may not always be reliable.
Derivation
Ambiguity comes from the Latin ambiguus, meaning 'going both ways' or 'uncertain.' In a GPS context, the signal is uncertain because it could be telling the receiver more than one thing about distance.
Why Pilots Care
Unresolved signal ambiguity can produce large position errors that affect navigation and situational awareness.
Analogy
It is like hearing a radio call with static and an echo at the same time. You may hear something, but you are not fully sure which part was the real message.
Grounding Statement
A GPS receiver needs clean satellite signals to compute a dependable position; unclear signals make that position less certain.
Intuition Check
Do not read ambiguity as just a vague or confusing idea. Here it means a specific GPS problem: the receiver cannot get one clear interpretation from the signals it is receiving.
Example Sentence 1
Flying low between tall ridges, the pilot noticed the GPS position jumping slightly, a sign of signal ambiguity caused by reflections off the terrain.
Example Sentence 2
Multipath reflections created signal ambiguity and shifted the indicated position by several hundred feet.