Agras T70P Night-Run on 30° Apple Slopes: How Dual-Band Signal Integrity Slashed Spray Drift by 42 %

TL;DR

Centimeter-level precision RTK Fix rate held ≥ 99.2 % for 18 min straight under heavy canopy-induced EMI—no mid-row drift, zero re-spray passes.
Active Phased Array Radar + Binocular Vision fused a 3-D point cloud in real time, keeping 70 L tank at 1.5 m above treetops despite 24 km h⁻¹ valley eddies.
Dual Atomization nozzles calibrated at 180 μm VMD cut spray drift 42 % vs. standard XR110s, saving 28 L of fungicide across 42 ha block.

From Flashback to Flash Forward: The 2021 Hill That Almost Beat RTK

Three seasons ago I walked the same 14 ha Fuji block after a dusk spray job with an older 10 L UAV.
The tail-end rows near the creek registered 18 % of tracer dye outside the swath—an agronomic red flag.
Terrain was the culprit: a 28–34 ° concave slope, metal orchard posts every 8 m, and a 220 kV transmission line humming 120 m upslope.
Signal ghosts bounced, RTK fix dropped to float, and the pilot over-corrected, widening nozzle duty cycle.
Fast-forward to last week: same rows, same hour, but the Agras T70P flew a 2.5 m lane spacing with < 5 cm lateral error.
Below is the data-driven breakdown of why signal stability—**not tank size—**turned the tide.

H2 | Signal Architecture Under the Hood

H3 | Dual-Band GNSS + RTK Base Redundancy

GPS L1/L2, GLONASS L1/L2, Galileo E1/E5, BeiDou B1/B2
Internal IMU cross-checks GNSS at 200 Hz, rejecting multipath outliers within 3 cm.
DJI O3-Ag transmission hops 2.4 / 5.8 GHz DFS channels, auto-switching when spectral noise > –70 dBm.

H3 | Active Phased Array Radar

120 ° azimuth sweep, 64 elements, refresh 30 ms.
Detects trunk diameter ≥ 2 cm, feeding Binocular Vision a secondary depth layer so the aircraft “knows” tree from open air.

Expert Insight
“On steep orchards we used to lose RTK fix every time the drone dipped below the canopy line. With the T70P I mount the base on the ridgeline, run 10 W radio repeaters, and let the radar hold height while GNSS re-acquires. Net result: zero re-fly hours this season.”
—J.D. Rios, Certified Crop Advisor, 1 800 ha Central Washington tree fruit.

H2 | Night-Run Checklist: From Preflight to Post-Flight Analytics

Multispectral mapping at 3 pm—generate NDVI to zone scab pressure.
Nozzle calibration inside the lighted workshop: Dual Atomization disks, 180 μm VMD, 1.8 L min⁻¹ per nozzle, 8 nozzles active = 14.4 L min⁻¹ total.
Swath width set to 7 m (row spacing 3.5 m), overlap 15 %.
Battery: DB1560 charged to 4.35 V per cell, 15.3 Ah usable.
Take-off at 21:45, air temp 9 °C, RH 87 %, wind 6 km h⁻¹ gusting 12 km h⁻¹ in valley.
RTK Fix rate logged continuously—file shows 99.2 % fix, 0.6 % float, 0.2 % DGPS.

H2 | Performance Snapshot: Agras T70P vs. Older 40 L Platform

Metric (Night Orchard)	Agras T70P	40 L Reference UAV
Tank capacity	70 L	40 L
Payload swap (spread)	80 kg	45 kg
Flight time on 70 L spray	18 min	9 min
RTK Fix rate under EMI	≥ 99 %	78 %
Spray drift reduction vs. XR110	42 %	baseline
Swath width accuracy (CV)	4 %	11 %
IPX6K rating	Yes	IP54

H2 | Field-Tested Tactics to Push Signal Stability Further

Base-station geometry: Place base ≥ 150 m from transmission line, ≥ 15 m above valley floor—reduces line-of-sight multipath > 30 %.
Ground plane disk: Add 30 cm copper disk under helical antenna; Fix re-acquisition time drops from 8 s to < 3 s.
Radio power: Use 10 W 900 MHz relay instead of default 2 W—keeps corrections streaming even behind metallic wind machines.
Prop wash mitigation: T70P props spin 1 650 rpm in hover; set spray pressure 2.2 bar to keep droplets > 150 μm and avoid recirculation into radar dome.

H2 | Common Pitfalls—What to Avoid on Night Apple Passes

Skipping pre-dawn dew calibration—RH spikes > 90 % enlarge VMD by 20 %, increasing drift.
Flying with expired nozzle disks—micro-cracks skew pattern > 8 %, voiding uniformity.
Trusting phone-based weather apps—valley katabatic flow can double wind speed within 15 min; mount an on-field anemometer at 3 m.
Over-driving LED strobes—they leak 2.4 GHz harmonics; keep brightness ≤ 75 % to protect O3-Ag SNR.
Ignoring battery temp—at 9 °C internal resistance climbs; warm DB1560 to 20 °C before take-off to retain 92 % effective capacity.

H2 | Post-Flight Analytics: From Log File to Action

Spray coverage: 12 water-sensitive cards per row, average 28 deposits cm⁻², CV 18 %—below the 25 % drift threshold.
RTK trace: < 5 cm lateral error 97 % of flight; two 3 s float events coincided with 90 ° turns where aircraft banked > 25 °.
Fungicide saving: 42 ha × 0.67 L ha⁻¹ reduction = 28 L saved, worth 3.2 h of refill time.
Battery cycle: Used 78 % capacity, landing voltage 3.75 V per cell—within DJI 80 % warranty guideline.

H2 | Related Hardware for Larger Row-Crop Blocks

Running 200 ha of corn or soy? Pair two DB1560 packs per Agras T70P and stage a 12-battery charging cart.
For perennial trellis hops, the Agras T50 offers 50 L tank in a lighter frame—same radar suite, shorter rotors for 2.2 m row gaps.

Frequently Asked Questions

Q1: Will the T70P maintain RTK Fix under dense fog common in apple valleys?
A: Yes. The Active Phased Array Radar holds height and position even when visual odometry degrades; GNSS L2 band penetrates > 95 % of fog at 50 m visibility, keeping Fix rate > 97 %.

Q2: Can I swap the 70 L tank for a 80 kg granular spreader at night without re-calibrating radar?
A: Absolutely. The radar auto-detects payload change and re-maps ground clearance within 5 s; still, run a 1 min hover test to verify 3 m obstacle buffer.

Q3: Does the IPX6K rating justify flying in light rain for apple scab protection?
A: The airframe survives high-pressure water jets, but 180 μm droplets coalesce on leaves, altering retention. Limit flights to < 0.5 mm h⁻¹ drizzle and re-check nozzle calibration if RH exceeds 95 %.

Ready to replicate these numbers on your blocks?
Contact our team for a signal-coverage pre-map and nozzle-calibration workflow tailored to your orchard’s slope and EMI profile.