Linear inspection drone mission template

Geometry, from the planner

Planned by OpenDroneKit with these inputs: two-leg route line about 310 m long inside a 360 x 160 m area, 45 m. The drawing is the planner’s actual output for that test site in Aukerman Park, Ohio, not an illustration.

Planner output · 34 waypointsLocal metres · north up

Plan · blue: flight path · ring: first waypoint · dashed: drawn area · shaded: structure

Elevation, looking north · x: east–west position (m), y: altitude above take-off (m) · 45 m · gimbal -90°

How is the linear mission laid out?

The route is sampled at a spacing from the camera footprint and forward overlap. The heading is locked to the direction of travel.

Long routes are split into numbered segments (1,500 m by default) so they can be flown in parts.

Also accepted by the planner as: linear, pipeline, rail, river.

Inputs

Parameter	Meaning	Default
`altitude_m`	Flight altitude in metres, relative to the take-off point unless an AMSL terrain model is loaded	60
`front_overlap_pct`	Forward overlap between consecutive photos; with the camera footprint it sets the capture spacing	80
`side_overlap_pct`	Overlap between neighbouring lines or rows; with the camera footprint it sets the line spacing	70
`speed_m_s`	Planned cruise speed, written to every export	5
`camera`	Camera profile used for footprint and ground-sample-distance estimates	mavic2pro
`gimbal_tilt_deg`	Camera pitch; left blank, the template's own default is used	-90
`linear_path_lonlat`	The route line to follow	—
`linear_segmentation_enabled`	Split a long route into numbered segments	true
`linear_max_segment_length_m`	Segment length when splitting (minimum 100 m)	1500
`inspection_dwell_s`	Hover time at each capture point	—

Footprint, line spacing and GSD come from the camera profile; the GSD calculator uses the same formulas.

What survives each export?

QGroundControl .plan and .waypoints: every point carries a DO_MOUNT_CONTROL gimbal command; 34 of 34 points are NAV_LOITER_TIME holds; 34 of 34 have a CONDITION_YAW heading lock; 34 DO_DIGICAM_CONTROL captures.
DJI WPML .kmz: gimbalRotate on every waypoint; hover action and toPointAndStopWithDiscontinuityCurvature turns at hold points; heading-locked points use smoothTransition; takePhoto at capture points; speed limited to 1-15 m/s.
Litchi CSV: 34 waypoints fit in one file (the exporter splits at 99).

Each format has known issues, listed on its page: QGC .plan · .waypoints · DJI WPML · Litchi CSV.

Limits

Without a drawn route line the plan follows the area's outline or long axis and warns that it did.
Planned without a terrain model the plan assumes flat ground at the launch elevation, and it says so in a warning.
Not flight-tested on an aircraft as part of these pages; the numbers above are the planner’s estimates.

Source and tests

Compiled by _compile_linear_inspection_primitive in mission/planner.py. The function is on public main (1ef6351); this drawing was planned with the development branch (0ae10e4), whose planner is ahead of main.

Tests in the development branch that exercise it:

tests/test_mission_constraints.py
tests/test_mission_exports_carry_the_plan.py
tests/test_standoff.py
tests/test_template_inventory_is_derived.py

Paths around or along something, single-point captures, and joined missions.

Orbit: Circles around a point of interest at one or more heights, camera aimed at the subject.
Closed loop: Continuous loops around a structure at one or more radii, without stopping at corners.
Lateral: Side-on photos of a linear asset from a parallel line at stand-off.
Waypoints: A route through drawn waypoints, with a choice of heading behaviour.
Panorama: A hover at one point, rotating to photograph the horizon for a stitched panorama.
360 bubble: A hover at one point covering the whole sphere below the horizon, for a 360 photo sphere.
Linked mission: Two or more saved missions joined into one sortie, with planned transitions between them.

All 22 templates: mission templates · mission planning.

Linear inspection