Definition
A unique digital signal pattern transmitted by each GPS satellite that appears random but is actually generated by a known mathematical sequence, allowing a GPS receiver to identify which satellite is transmitting and to measure how long the signal took to arrive.
Plain English
A special signal pattern that looks random but isn't. Each GPS satellite has its own pattern, so the receiver can tell the satellites apart and figure out how far away each one is by timing the signal.
Context Anchor
Seen in GPS system explanations, especially when describing how a GPS receiver identifies satellites and measures distance to them.
Derivation
Pseudo' comes from the Greek 'pseudes' meaning false. 'Pseudo-random' means it looks random but isn't truly random. Knowing this helps: the pattern only seems random — the receiver and satellite both know exactly what the sequence is, which is what makes it useful for measuring signal travel time.
Why Pilots Care
Enables reliable position fixes by letting the receiver distinguish one satellite from another and compute exact distances even when signals are weak or overlapping.
Grounding Statement
The receiver compares the incoming satellite pattern with its own stored pattern and uses the time difference between them to help find distance.
Intuition Check
Pseudo-random does not mean truly random or guessed. It means the pattern looks random, but is planned, repeatable, and known to the GPS receiver.
Example Sentence 1
The GPS receiver identifies each satellite by its unique pseudo-random code and uses the timing of that signal to calculate distance.
Example Sentence 2
Each GPS satellite broadcasts a unique pseudo-random code so the receiver can identify which satellite is sending which signal.