How to Scout Remote Vineyards with the Agras T100—And Keep It Field-Ready for the Next Flight

META: Step-by-step field protocol for multispectral vineyard scouting, drift-minimised nozzle tuning, centimetre-level RTK positioning, and post-mission cleaning of the DJI Agras T100.

Dr Sarah Chen, Plant Physiology & Precision Agriculture, University of Stellenbosch

The pinot block sits 600 m above the valley floor, reachable only by a single-track dirt road that turns to grease after the first winter storm. Last season a troop of baboons worked through 2 ha in two nights; this season I’m out-running them with an Agras T100 and a five-band multispectral payload. Below is the exact workflow my team and I now use to turn a 12-minute autonomous flight into a management decision—while making sure the aircraft comes back clean, calibrated, and ready for the next dawn sortie.

1. Pre-Flight: From Office to First RTK Fix

1.1 Weather & Drift Check
Spray drift is irrelevant today because we’re in “scout-only” mode, but the same wind玫瑰 that moves droplets also smears your NDVI layers. I hold the T100’s controller up, let the built-in anemometer stabilise, and log anything above 4 m s⁻¹. Above that, you’ll see striping in the orthomosaic later.

1.2 Nozzle Swap—Even When You’re Not Spraying
Sounds backwards, right? The T100 ships with 8 stainless nozzles optimised for 2–4 L min⁻¹. For pure scouting we swap in the red-coded “blank” inserts. They weigh 3 g less per head, shaving 24 g total and removing micro-vortices that can blur the multispectral imager hanging on the front rail. One season of data showed a 7 % sharper edge definition on trellis wires—handy when you’re counting individual shoots.

1.3 RTK Base & Fix Rate
We run a local base station on a 2 m tripod pegged into the vineyard headland. The T100 needs a 15-s Fix rate ≥ 95 % before it will allow “ centimetre precision” logging. Anything lower and the elevation layer drifts, so you can’t tell whether the chlorosis you see is nutrient stress or just a 10 cm altitude artefact. Power-cycle the aircraft if Fix stays at 94 %—the ublox module sometimes hangs onto a float solution too long.

2. Mission Design: Swath Width vs Vine Row Spacing

The multispectral sensor has an across-track field of view of 47.6°. At 30 m AGL that gives a 26 m swath. My vine rows are 2.4 m apart, so one pass covers eleven rows with 8 cm end-lap. I set the flight speed to 5 m s⁻¹—any faster and rolling shutter blur turns the vine edges into pink mush. If you’re on a steep hillside (ours hits 18 % slope) drop speed to 4 m s⁻¹; the T100’s pitch-compensating gimbal keeps the camera nadir within ±2°, but the slower traverse gives the IMU more time to correct.

3. In-Flight Reality: When Wildlife Photobombs Your NDVI

Half-way through the third leg last Tuesday the RGB feed twitched—something beige flashed across the vines. A caracal, ear-tagged two years ago by the local conservation trust, had leapt onto a post to scan for guinea fowl. The T100’s front stereo cameras flagged the obstacle at 22 m, auto-braked, then resumed. I kept the mission running; the multispectral shutter never blinked. Because we’d set the “pause on obstacle” toggle off, the data set stayed continuous—no black wedge in the orthophoto, no interpolation gap in the VARI index. That’s the kind of real-world nuance you only discover once you trust the sensor chain enough to let it handle a 12 kg platform skimming above rare predators.

4. Landing & Immediate Field Care

4.1 Dust Down
The farm road is powdered shale; one rotor wash and the T100 looks like breaded cutlet. I keep a 1 L squeeze bottle of de-ionised water and a goat-hair brush in the truck. First rule from the elecfans maintenance note: keep grit away from the gimbal cups. I tilt the gimbal to 90°, blow off loose dust with a manual rocket blower, then brush the carbon-fiber arms lengthwise—never across—so the matte coating stays intact.

4.2 Battery & Tank Hygiene
Even on scouting days I fill the 40 L tank quarter-way. A sloshing liquid mass damps vibrations and keeps the diaphragm pump seals wet. Back at the shed I drain the remainder through the rear tap, run 2 L of clean water through the lines, then pop the battery out while it’s still warm—thermal shock is less brutal than letting it cool coated in acidic dew.

5. Data Wrangling: From DNG to Vineyard Action

5.1 Calibration Panel
I place the calibrated reflectance tile in the same light zone the aircraft will fly through—shadowed panels can shift NDVI by 0.03, enough to mask early powdery mildew stress. Capture the tile at the start and end of the mission; the T100’s multispectral suite auto-tags the frames with GPS and sun-angle metadata.

5.2 Stitching & Index Layer
Agisoft Metashape ingests the 1 280 DNGs in 22 min on a Ryzen 9 laptop. I export five bands (Blue, Green, Red, Red-Edge, NIR) then calculate a modified VARI formula:
VARI = (Green – Red) / (Green + Red – Blue).
Anything below –0.04 in our block correlates with a 0.6 °Brix drop at harvest. Last season we validated that with 15 hand-sampled panels—R² = 0.78, good enough to send the picking crew to the western rows first.

6. Cleaning Protocol: IPX6K Doesn’t Mean “Hose With Impunity”

The T100 carries an IPX6K rating—100 bar jets at 80 °C for 3 min. Handy, but vineyard tanks carry copper sulfate residues that etch anodised aluminium. My routine:

Remove gimbal lock & fit the plastic splash guard.
Rinse with 40 °C water, low-pressure fan nozzle, top-down.
Soft-bristle toothbrush on the eight nozzle seats—this is where crystals hide and mis-align your spray cone next time you switch to fungicide mode.
Finish with a 50 % isopropyl wipe on the RTK antenna housing; mineral deposits here can attenuate the L2 signal and drop your Fix rate below that critical 95 %.

Store arms half-extended in the travel cradle; fully folded compresses the motor dampers and leaves flat spots that show up as 60 Hz jitter in your next multispectral roll.

7. Calibration & Record-Keeping

Every tenth flight I run a nozzle calibration sequence: fill tank to 20 L, set flow-rate to 2.2 L min⁻¹, collect spray for 120 s on a digital scale. The T100’s pump PID should hold ±2 %. If drift hits 5 %, back-flush with 1 % citric acid; usually that’s residue narrowing the orifice. Log the number in a shared Google Sheet—over a season you’ll see a 1 % creep as diaphragm fatigue sets in, your cue to swap the pump head before it fails mid-mission.

8. Spare-Field-Kit Checklist (Print & Laminate)

2 spare red blank nozzles
1 collapsible 1 L rinse bottle
Goat-hair brush & rocket blower
Microfiber cloths (never the same ones used for tractor windows—diesel film smears optics)
3 mm hex driver for arm locks
USB-C cable for controller firmware flashes

9. When You Need a Second Opinion

Sometimes the index map throws an anomaly you can’t ground-truth—maybe a strange circular chlorosis pattern that turns out to be an old irrigation leak. If you want to bounce the data off someone who’s logged 400 h on the T100, send the screen-grab via WhatsApp and we’ll walk through the settings layer by layer.

Ready for your own Agras T100? Contact our team for expert consultation.