A ship reports where it is. GHAST checks whether that is possible.
Every vessel broadcasts its position, speed and course. When that signal is jammed or faked, the numbers stop fitting together: a turn too sharp for the hull, a jump with no time to make it, a position frozen while the speed says the ship is moving.
GHAST learns how each vessel normally moves and flags the reports that break from it. Then it gathers the evidence, says what it thinks happened and how sure it is, and leaves the decision to a person.
Try to fool it.
This ship is heading north east. Drag the red dot to where a spoofer might claim it is, or focus it and use the arrow keys.
GHAST knows how far the ship could have moved since its last report. Stay inside the dashed circle and nothing happens. Step outside and it flags you.
Illustration