Ultra-Wideband Ranging

• Fields t, dist_m1, dist_m2, dist_m3, valid_m1, valid_m2, valid_m3 (7 cols).
• Present on indoor_3, outdoor_1, transition_1..3 (+ static).
• Decawave TREK1000; only 3 of 4 anchors published; no anchor geometry ships.
• The underlying Decawave ROS message shape carries four distance[] / valid[] slots, but the public CSV export preserves only m1..m3; the fourth lane is dropped at extraction time and later reconstructed as (distance=0, valid=false) by the maintainer csv2bag.py path.
• valid_mk is perfectly redundant with dist_mk > 0: only two states occur — missing (dist == 0 & valid == 0) and valid (dist > 0 & valid == 1). Gate on either.
• Anchor m1 returns most, m3 least; transition_1 misses >55% on m2/m3.
• Delivered rate 1.7–6.2 Hz on flights (7 Hz nominal) with multi-second blackout gaps (max dt 18–71 s).
• Time-gate updates; do not interpolate across gaps.
• Valid ranges reach ~40–65 m outdoors; reliable below ~15 m.