Every bearing adds information across its line of sight and none along it. Stack them into the Fisher information J and the Cramér–Rao bound J⁻¹ is the best fix anyone can make — the number behind L14's PDOP tile, DRMS = PDOP·R̄·σθ. Where J goes singular there is a seam, and read from the other side, geometry is information: where their sensors can't see you well is a place you can fly.
One bearing as one row of information, the Fisher information matrix and the Cramér–Rao bound, the ellipse read from eigenvalues, L14's PDOP named, and the seams that range fills and jamming reopens.
FlashcardsKey terms and relations from the lesson, in a self-test deck.
Pre-flightFive questions to work before class — anyone can be called to the board.
SlidesThe deck we work through in class — an HTML deck you can annotate in the browser, with a print view for saving a PDF.
DemoDrag a passive network around a map colored by its CRLB, click anywhere for the error ellipse, and fly a straight leg across the seam — then give one site a radar and watch the seam close.