Survey3 Mapping Camera

This page tells you how to set up, fly and process the MAPIR Survey3W on the TerraHawk. The mount, its fit in the Fuselage Mid, and the balance are on two other pages. Refer to the mapping payload section of the parts list, and to the custom parts page. This page starts from there. Checked 2026-09-26.

The camera

From MAPIR’s product page:

Spec	Survey3W
Sensor	Sony Exmor R IMX117, 12MP Bayer RGB, 6.20 x 4.65 mm
Image	4,000 x 3,000 px
Lens	3.37 mm f/2.8, 87° horizontal field of view, -1% distortion (not fisheye)
Shutter speeds	1/2000 s down to 60 s, or auto
ISO	50, 100, 200, 400, or auto
Interval	1.5 s per JPG, 2.75 s per RAW+JPG
Files	JPG (8-bit) or RAW+JPG (12-bit), micro SD up to 512 GB
Power	5.2 V over USB or its own 1,200 mAh battery; 0.3 A idle, 0.33 A shooting
Mass	50 g without battery, 76 g with
Size	59 x 41.5 x 36 mm
Trigger	2,000 µs PWM pulse on the HDMI port; 1,000 µs is idle
Feedback	3.3 V exposure pulse on the HDMI port, about 100 ms after the trigger
GPS	External only; MAPIR’s USB GPS receiver ships with the camera
Price	$400, the same for every filter

The IMX117 is a rolling-shutter sensor. Its rows are read out one after another, so a fast-moving aircraft skews each frame slightly. Photogrammetry software corrects for this if you turn the correction on (refer to Processing).

Which variant

Every Survey3 costs $400 and has the same sensor. The variants differ in filter and lens.

Choice	Pick	Why
Lens	Survey3W (3.37 mm, 87°)	The narrow Survey3N (8.25 mm, 41°) has an along-track footprint of only 68 m at 120 m. At cruise and the 1.5 s interval that is 56% forward overlap, too little to map from
Filter	RGB for maps, terrain and orthophotos	RGN or OCN if you want NDVI crop health; NGB for water and submerged plants; NIR and RE for specialist indices

The NIR-capable filters need two extra steps: a photograph of a reflectance calibration target before each flight, and processing in MAPIR Camera Control. RGB needs neither.

Wiring to the LUX F765

The flight controller for the first flights is the Lumenier LUX F765 NDAA (Ryan, 2026-10-04; params/board-luxf765.parm). The camera does not fly on the first build, so the board file sets output 8 and the camera off and carries the rows below as comments, to set when the camera flies (2026-10-19). The trigger is on output 8 (M8), in timer group 5 to 8 with the elevons and the pusher (all PWM, no DShot motor). The strobe goes on the S2 pad (output 10), set as a GPIO input with SERVO10_FUNCTION -1.

Camera lead	LUX F765 pad	ArduPilot
PWM trigger (white)	M8 signal	`SERVO8_FUNCTION = 10` (camera trigger)
Exposure strobe	S2 pad (PB1, GPIO 59)	`CAM1_FEEDBAK_PIN = 59`, `SERVO10_FUNCTION = -1`
Ground	A ground pad
Power	A 5 V pad, to the camera’s USB	As on the 6C Mini below

The strobe is 3.3 V, which the F765’s pins take directly.

Wiring to the NxtPX4v2

The flight controller for the first flights was the HKUST NxtPX4v2 (Ryan, 2026-10-04, replaced by the LUX F765 the same day; params/board-nxtpx4v2.parm). The trigger is on output 8, in timer group 7 to 8 with the pusher (both PWM, no DShot motor). The strobe goes on the AUX2 pad, a plain GPIO on the H743.

Camera lead	NxtPX4v2 pad	ArduPilot
PWM trigger (white)	PWM 8 signal	`SERVO8_FUNCTION = 10` (camera trigger)
Exposure strobe	AUX2 pad (PC1, GPIO 82)	`CAM1_FEEDBAK_PIN = 82`
Ground	PWM 8 ground
Power	A 5 V pad, to the camera’s USB	As on the 6C Mini below

The strobe is 3.3 V, which the H743’s pins take directly. MicoAir’s pinout sheet and ArduPilot’s README agree that the AUX2 pad is PC1.

Wiring to the Pixhawk 6C Mini

The flight controller for the first flights was the Pixhawk 6C Mini (2026-09-27 to 2026-10-04). The camera goes on the FMU’s AUX pads, in group AUX 1 to 4, which has no motor in it. The pusher is on AUX 5.

Camera lead	6C Mini pad	ArduPilot
PWM trigger (white)	AUX 1 signal	`SERVO9_FUNCTION = 10` (camera trigger)
Exposure strobe	AUX 2 signal (GPIO 51)	`SERVO10_FUNCTION = -1` (GPIO), `CAM1_FEEDBAK_PIN = 51`
Ground	AUX 1 ground
Power	A 5 V pad, to the camera’s USB	Camera switches on with the aircraft; its battery can stay out to save 26 g

The strobe is 3.3 V. The pins of the FC take it directly. The Lucid wiring below applies only if the Lucid is fitted.

Wiring to the Lucid H7 Wing

The timer groups of the board come from ArduPilot’s hardware definition, which the Lucid H7 Wing includes. The groups are outputs 1 and 2, 3 and 4, 5 and 6, 7 to 10, 11 and 12, and 13. Outputs 1 to 4 carry the DShot lift motors. Outputs 7 and 8 carry the elevons. The camera goes on outputs 9 and 10, in the same group as the elevons. That group runs PWM only.

Camera lead	Lucid pad	ArduPilot
PWM trigger (white)	Output 9 signal	`SERVO9_FUNCTION = 10` (camera trigger)
Exposure strobe	Output 10 signal (GPIO 59)	`SERVO10_FUNCTION = -1` (GPIO)
Ground	Output 9 ground
Power	A 5 V pad, to the camera’s USB	Camera switches on with the aircraft; its battery can stay out to save 26 g

The strobe is 3.3 V. The pins of the FC take it directly.

ArduPilot parameters

Current ArduPilot uses the CAM1_ names. Older firmware used CAM_ and CAM_FEEDBACK_. The values come from the camera shutter guide and MAPIR’s trigger guide:

Parameter	Value	Why
`CAM1_TYPE`	1	Servo trigger. Reboot after setting it
`SERVO9_FUNCTION`	10	Output 9 drives the trigger (6C Mini). On the LUX F765 and the NxtPX4v2: `SERVO8_FUNCTION` 10
`CAM1_SERVO_ON`	2000	The Survey3’s take-a-photo pulse
`CAM1_SERVO_OFF`	1000	Idle. Never 1500, which puts the camera into USB transfer mode
`CAM1_DURATION`	0.1	Seconds the pulse stays high
`CAM1_INTRVAL_MIN`	1.6	Just above the camera’s 1.5 s JPG interval, so ArduPilot never asks faster than it can shoot
`SERVO10_FUNCTION`	-1	Output 10 becomes a GPIO input (6C Mini, and the LUX F765’s S2 pad). The NxtPX4v2’s AUX2 pad is already a GPIO
`CAM1_FEEDBAK_PIN`	51	On the LUX F765: 59, the S2 pad (PB1). On the NxtPX4v2: 82, the AUX2 pad (PC1). Output 10’s GPIO number on the Pixhawk 6C Mini: output 10 is AUX 2, GPIO 51, because the IO co-processor drives MAIN 1 to 8 (th-avionics, Pixhawk6C hwdef). 59 is correct only on a board with no IO co-processor, such as the Lucid H7 Wing below. With the wrong number, the feedback never arrives and each photo carries the trigger position
`CAM1_FEEDBAK_POL`	1	The strobe goes high when the photo is taken

On the camera, turn the Interval option off. If it is on, the camera also shoots on its own timer.

Test on the bench:

WARNING: Remove the props before the bench test. A prop that starts can cause injury.
In Mission Planner, right-click the map and select Trigger Camera NOW.
Check the log for both TRIG (the command) and CAM (the actual exposure) messages.

The feedback pin matters here. The exposure comes about 100 ms after the trigger, which is 2 m at cruise. CAM records where the aircraft really was.

Planning a survey

Across-track is the 87° axis, along the span. Along-track is the 69° axis. All the figures are computed from the sensor and lens above, at the 20 m/s cruise in the manual.

Altitude	Ground resolution	Footprint across x along	Photo spacing at 80%	Line spacing at 70%
60 m	2.8 cm/px	110 x 83 m	16.6 m	33 m
80 m	3.7 cm/px	147 x 110 m	22.1 m	44 m
100 m	4.6 cm/px	184 x 138 m	27.6 m	55 m
120 m	5.5 cm/px	221 x 166 m	33.1 m	66 m

The shooting interval sets the minimum altitude, not the resolution. Photogrammetry needs about 75 to 80% forward overlap. At 1.5 s per photo and 20 m/s, the aircraft covers 30 m between shots. Thus the along-track footprint must be long enough to overlap that distance:

Airspeed	75% forward overlap	80% forward overlap
16 m/s (`AIRSPEED_MIN`)	70 m or higher	87 m or higher
20 m/s (cruise)	87 m or higher	109 m or higher

Thus, fly at 110 to 120 m at cruise, or at 90 to 100 m at 16 to 17 m/s for finer detail. Any lower altitude leaves gaps, whatever the mission plan. RAW+JPG at 2.75 s would need about 200 m, which is above the 120 m (400 ft) limit. Shoot JPG only.

Fly the lines crosswind. Ground speed sets the photo spacing. At 120 m and 80% overlap, the camera keeps up with 22 m/s over the ground. Thus a 20 m/s cruise with a tailwind of more than 2 m/s misses frames on the downwind legs. Crosswind lines keep the ground speed near the airspeed in both directions.

Shutter. In daylight, lock the shutter at 1/1000 s or faster, with ISO 100 to 200. At 20 m/s that is 20 mm of motion, 0.36 px at 120 m. In shade, auto exposure can drop to 1/500 s or slower and blur the frame.

Coverage. At 120 m with 70% side overlap, each line sweeps 66 m. At 20 m/s that is about 475 ha an hour before turns. Fixed-wing turns take a third or more of a survey. Plan on about 300 ha an hour.

Rules. Part 107 limits altitude to 400 ft (122 m) and requires visual line of sight. To keep a 1.5 m wingspan in sight, a practical survey block is about a square kilometre around the pilot. That is well under what one pack can cover.

Mission Planner survey

Use Plan, right-click, Auto WP, Survey (Grid) with a custom camera:

Field	Value
Sensor width x height	6.20 x 4.65 mm
Image width x height	4,000 x 3,000 px
Focal length	3.37 mm
Orientation	Long side across the flight line (landscape)
Overlap / sidelap	80% / 70%
Altitude	110 to 120 m
Speed	20 m/s

The grid tool writes DO_SET_CAM_TRIGG_DIST at the start of the lines and a distance of 0 at the end. Thus the camera only shoots on the survey legs. Start the mission with a VTOL take-off and end it with a VTOL landing.

Processing

Transfer the JPGs from the SD card. Download the .bin log of the flight.
Geotag the images: in Mission Planner, use Ctrl-F, Geo ref images, with the CAM messages. MAPIR Camera Control can also geotag from the log.
Build the map in WebODM (OpenDroneMap, which you can host in Docker). Turn on the rolling-shutter correction (rolling-shutter), because the IMX117 reads out row by row. WebODM produces the orthophoto, the elevation models and the point cloud.
NIR filters only: before you build the index maps, calibrate reflectance with the target images in MAPIR Camera Control.

Manuals

MAPIR’s documents for the camera, mirrored for the builder behind the same login as the kit manual. Each page links its original PDF:

Survey3 Quick Start Guide: camera modes, settings, the PWM trigger and the LED codes (14 pages, PDF)
Survey3 Cameras: the product sheet: specifications, lenses, filters, mounts and dimensions (2 pages, PDF)
NT9666x Wi-Fi Command User Guide: the camera chip maker Novatek’s HTTP command reference, which MAPIR distributes as the Survey3 Wi-Fi manual (68 pages, PDF)

Watch

From the kit’s makers, Nomadium Robotics, in their Pathfinder series:

I Tried Building a Mapping Drone for Large-Scale Photogrammetry (40 min): the TerraHawk mapping with RTK and a survey camera

Source: docs/survey3.md in the repo. Edit it there; this page is generated.