Lesson 35 — Fusion Under Threat#
A pop-up SAM that was never on the laydown, one aircraft, one RWR, and bearings that arrive one at a time. The Kalman filter fuses them as they land — 1/σ² = 1/σ₁² + 1/σ₂², one measurement after another — but a bearing measures direction, never distance. A stationary emitter off the route is observable from a straight leg; a moving one is not, until the own-ship turns. Bearings alone can't tell you range — you have to move to see, and the turn that sees best spends the most exposure. The Final Project checkpoint is due today.
Fusion Under Threat
From L14's batch least squares to a recursive estimator, the Kalman filter's predict and update, the EKF's linearized bearing, the bearings-only observability conditions, and the price of the maneuver that buys range.
FlashcardsReview deck
Key terms and relations from the lesson, in a self-test deck.
Pre-flightPre-flight quiz
Five questions to work before class — anyone can be called to the board.
SlidesLesson slides
The deck we work through in class — an HTML deck you can annotate in the browser, with a print view for saving a PDF.
DemoBearings-Only Tracker
Run an EKF on one aircraft's RWR bearings and watch the error ellipse collapse — or refuse to — then fly a dogleg and count the seconds it costs inside the threat ring.