Camera-LRF Boresight (Derived)
No LRF extrinsic appears in any published YAML; the deployed flight stack assumes identity. A launch/node parameter-name mismatch, R_PL written vs R_LP read, pins it to identity regardless.
The camera↔︎LRF rotation must be derived.
The nav camera and LRF are co-mounted, both nadir (the Ingenuity-analog arrangement), so the rotation is expected to be near identity.
Flat-floor least squares on indoor mocap (~334 Hz) + LRF range (~30 Hz), fitting p_z = z0 + (R·l)_z + r·(R·b)_z for boresight b, lever l, floor z0:
- Best-conditioned full-lever closed-form: boresight (rigid-body frame)
[−0.025, +0.017, −0.9995], 1.7° off nadir, residual RMS 19 mm (≈ the 25 mm LRF spec), predicted beam ≈ pixel (1021, 751) vs principal point (1050, 732) — essentially image center. - The off-nadir is only resolved to ~2–6°: the indoor lever arm is unobservable and aliases into tilt (full-lever ~1.7°, no-lever ~4°, model-free hover-slope ~6°). The z-component is stable run-to-run; the tilt azimuth is not repeatable.
- The estimate is in the OptiTrack rigid-body (marker) frame, whose alignment to the PX4-IMU and nav camera is itself unknown, so it bounds rather than isolates the true camera↔︎LRF tilt.
Conclusion: the camera↔︎LRF rotation is identity to within a few degrees, beam at image center; nothing finer is resolvable from this data.
The lrf_range value is a raw nadir-ish slant range — rotate it into the gravity frame with the IMU attitude for a vertical AGL, and reject the Laser Range Finder sentinels first.
To convert a measured beam pixel (u,v) (from a static-wall/IR-indicator recording, which is not in the download) to the rotation:
- undistort with the klu1 radtan intrinsics (fx 1140.57, fy 1138.23, cx 1050.43, cy 731.67) to a normalized ray;
- take the LRF boresight in camera frame as
normalize([x, y, 1]); - map
+z_camonto it.
Roll about the beam is unobservable for a 1-D LRF.
The calibration tests that aim to resolve this extrinsic more tightly are tracked under Camera-LRF Extrinsic Calibration Tests.