Conventions

These hold everywhere in the code, the scenario files and the interface.

Quantity	Convention
Frame	local East-North-Up: x East, y North, z Up, metres
Altitude	z above the local ground plane; above mean sea level when terrain is loaded
Azimuth	from North, positive clockwise (towards East); returned in (−180°, 180°]
Elevation	from the horizontal plane, positive up
Heading	direction of horizontal motion, same convention as azimuth
Radial velocity	\(v_r = \dot R\), positive when the target recedes
Doppler	\(f_d = -2 v_r / \lambda\): closing targets have positive Doppler
Angles in code	radians; degrees only in fields ending _deg
Power	watts in linear expressions, dB / dBm in log form; \(10\log_{10}\) for power ratios
Time	seconds of simulated time; the engine advances in fixed steps dt

The helpers in radarsim.physics.geometry (polar_from_enu, enu_from_polar, azimuth_from_enu, wrap_to_pi) are the only place these conversions are written out; everything else calls them.

The extended Kalman filter keeps its own internal polar angle (atan2(y, x)) and is fed Cartesian positions by the tracker, so its convention never leaks out.