Cross-bearing fix (drag any marker)

Receiver (R1/R2/R3) Emitter (true) Bearing LOP Computed fix + 1σ ellipse
Geometry

Drag the receivers and emitter. The cut angle between the two bearings sets the shape of the error ellipse.

Cut angle
between bearings
CEP
50% radius
Ellipse 1σ a × b
semi-axes (km)
Fix error
est vs true

CEP ≈ 0.75·√(σx²+σy²) from the 1σ ellipse. Each bearing carries ±2° uncertainty; cross-range error grows with range, so a ~90° cut gives a tight, near-circular ellipse while a shallow cut stretches it along the line of sight.