Definition
A signal that appears random but is actually generated by a known, repeatable mathematical sequence. In GPS, each satellite transmits its own unique PRN code, which the receiver uses to identify that satellite and measure how long the signal took to arrive.
Plain English
A signal that looks like random static but is really a known pattern. Each GPS satellite has its own pattern, like a fingerprint, so the receiver can tell which satellite sent which signal.
Context Anchor
Seen in GPS and other satellite-navigation discussions, avionics manuals, and satellite status pages. A PRN number usually identifies a particular satellite code.
Derivation
Pseudo comes from the Greek for 'false' or 'apparent.' The signal is not truly random — it just looks that way to anything that doesn't know the underlying pattern. Calling it 'pseudo random' captures that idea: random in appearance, predictable to those with the key.
Why Pilots Care
Allows a GPS receiver to distinguish one satellite from another and compute accurate position fixes.
Analogy
A PRN code is like a name tag hidden inside a signal. It looks like a jumble from the outside, but the receiver knows the pattern and can tell who sent it.
Intuition Check
PRN does not mean unwanted radio static here. It means a planned signal pattern that looks random but is useful because the receiver already knows it.
Example Sentence 1
Each GPS satellite is identified by its own PRN, which the receiver locks onto to calculate range.
Example Sentence 2
Each GPS satellite broadcasts a unique PRN so multiple satellites can transmit on the same frequency without interfering.