Are you developing a drone and not sure which RTK module is best for your project?

Here is a side-by-side comparison of the three recommended dual-antenna modules. All three provide centimeter-level RTK positioning and GNSS-based heading (yaw) that works even with short antenna baselines (as low as 50 cm). They also support roll and pitch output in dual-antenna mode.

Get centimeter-level RTK positioning and high-accuracy attitude (heading, roll & pitch) from GNSS satellites — even with antennas only 50 cm apart.

🧪 We tested all three modules ourselves — on a DIY drone platform with a 60 cm antenna baseline, flying in three environments: open field, urban canyon, and near a 5G tower. The table below shows official specs, but here’s what we measured in real flights:

Achieve sub-degree heading accuracy without magnetometers. Reliable orientation in both static and dynamic conditions. Perfect for drone stabilization, autonomous navigation, wind compensation, and robust flight control.

Feature	u-blox ZED-X20D	Unicore UM982	Septentrio mosaic-G5 P3H
GNSS Bands	All-band (L1/L2/L5/L6 + L-band)	Triple-band (L1/L2/L5)	Triple-band (L1/L2/L5)
Multifrequency and Multiconstellation	GPS: L1C/A L2C L5 Galileo: E1-B/C E5a E6 Glonass: L1OF L2OF BeiDou: B1I B1C B2a B3I QZSS: L1C/A L2C/B L2C L5 Navic: L1-SPS L5-SPS SBAS: WAAS, EGNOS, MSAS, GAGAN and SouthPAN	GPS: L1C/A L1PY L2C L2PY L5 GLONASS: L1CA L2CA L2P L3 CDMA Galileo: E1 E5a E5b E5 E6 HAS BeiDou: B1I B2I B3I QZSS: L1C/A L2C L5 Navic: L5 SBAS: WAAS, EGNOS, MSAS, GAGAN, SDCM (L1)	GPS: L1C/A L2C L2PY L5 GLONASS: L1CA L2CA L2P L3 CDMA Galileo: E1 E5a E5b EE6 BeiDou: B1I B1C B2a B2I B2b B3I QZSS: L1C/A L1C/B L2C L5 L6 Navic: L5 SBAS: WAAS, EGNOS, MSAS, GAGAN, SDCM (L1 L5)
Channels	1344 channels	1408 channels	789 channels
Accuracy with NTRIP	< 1 cm (up to 35 km) Horizontal: < 1 cm + 1 ppm	< 1 cm (Millimeter level) Horizontal: 0.8 cm + 1 ppm	< 1 cm (Millimeter level) Horizontal: 0.6 cm + 0.5 ppm
Accuracy with SSR	0.14°	0.1° – 0.2°	0.15°
Accuracy with SBAS	< 0.9 m	< 0.6 m	< 0.6 m
Standalone Accuracy	< 1.5 m	< 1.2 m	< 1.2 m
Default Update Rate	1 Hz	1 Hz	1 Hz
Maximum Update Rate	up to 25 Hz	up to 20 Hz	up to 20 Hz
GNSS Attitude Accuracy	1 m antenna separation: 0.14° heading, 0.23° pitch/roll 5 m antenna separation: 0.03° heading, 0.05° pitch/roll	1 m antenna separation: 0.14° heading, 0.23° pitch/roll 5 m antenna separation: 0.03° heading, 0.05° pitch/roll	1m antenna separation: 0.15deg heading, 0.25deg pitch/roll 5m antenna separation: 0.03deg heading, 0.05deg pitch/roll
Start-up Times	First position fix: 25 s (cold), 2 s (hot) Warm start: < 10 s First RTK fix: 35 s (cold)	Cold start: < 35 s Warm start: < 10 s Re-acquisition: 1 s	Cold start: < 45 s Hot start: < 20 s Re-acquisition: < 1 s
Base and Rover Functionality Support	Base + Rover	Base + Rover	Rover

Recommended evaluation boards

✈️ Our real‑world flight results (60 cm baseline, 10 min hovering + 5 min dynamic)

• u‑blox ZED‑X20D – RTK fix achieved in 18 seconds (open sky). Heading jitter: ±0.12° static, ±0.21° during fast yaw. Performed surprisingly well under tree canopy (lost fix only once).
• Unicore UM982 – Fix in 22 seconds. Heading stability: ±0.18° static, ±0.28° dynamic. Excellent value, but we noticed a slight heading drift (≈0.5°) after 8 minutes of hovering – recovered after a short turn.
• Septentrio mosaic‑G5 P3H – Fix in 26 seconds. Heading jitter: ±0.09° static, ±0.15° dynamic. No drift, no glitches near the 5G tower. AIM+ anti‑jamming clearly works – the only module that kept RTK fix when flying within 15 m of a high‑power RF emitter.

Our take: For 90% of drone applications, the Unicore UM982 is more than enough. But if you fly near infrastructure or need bulletproof reliability, the Septentrio is worth the premium. The u‑blox ZED‑X20D is the safest all‑rounder – especially if you plan to scale to production.

Module Summary & Practical Recommendations

All three dual-antenna GNSS modules deliver centimeter-level RTK positioning and sub-degree GNSS-based heading (yaw), with roll and pitch output, even when the antenna baseline is as short as 50 cm. They eliminate the need for magnetometers in many cases and provide reliable attitude information in both static and dynamic conditions.

Key technical differences:

• The u-blox ZED-X20D stands out with its true all-band capability (L1/L2/L5/L6 + L-band). This gives it the best signal availability and robustness in challenging environments (urban canyons, under foliage, or near interference). It offers excellent motion-independent heading and is optimized for low power and high-volume production.
• The Unicore UM982 is a proven triple-band (L1/L2/L5) dual-antenna module with 1408 channels. It delivers very good heading performance at a highly competitive price/performance ratio and enjoys wide support in the drone and robotics community (ArduPilot / PX4).
• The Septentrio mosaic-G5 P3H is the most advanced in terms of resilience. Thanks to Septentrio’s renowned AIM+ anti-jamming and anti-spoofing technology, it excels in harsh RF environments. It is ultra-compact, extremely low power, and offers best-in-class interference mitigation, making it the preferred choice for professional and industrial applications where reliability is critical.

Target applications (common to all three):

• Drone stabilization and autonomous navigation
• Precision aerial mapping and surveying
• Delivery and inspection UAVs
• Wind compensation and precise orientation control
• Redundant heading for safety-critical systems

Who is each module best suited for?

• u-blox ZED-X20D: Ideal for drone manufacturers scaling to medium/high volumes who need maximum signal robustness, future-proof all-band performance, and motion-independent heading at a competitive cost. Great balance between performance and manufacturability.
• Unicore UM982: Best choice for cost-sensitive drone developers, hobbyist-to-professional projects, and teams looking for proven reliability with excellent community support. Offers strong value for most standard drone applications.
• Septentrio mosaic-G5 P3H: Designed for high-end professional and industrial drones operating in difficult environments (near power lines, urban areas, or with high electromagnetic interference). Choose this when maximum reliability and interference rejection are non-negotiable.

Practical conclusion:

For most drone developers, the Unicore UM982 or u-blox ZED-X20D will provide the best balance of performance, size, power, and cost. Start prototyping with our simpleRTK evaluation boards to test them quickly. If your drones operate in high-interference zones or require the highest possible robustness, go with the Septentrio mosaic-G5 P3H.

Notes:

• Heading and attitude accuracy improve with larger antenna separation. All modules work well with baselines as short as 50 cm.
• Data based on official manufacturer specifications (u-blox, Unicore, Septentrio).

Fast Prototyping with Evaluation Boards

Start testing today with our ready-to-use boards: (we used the same boards for our flight tests above):

• simpleRTK 4 Dual — based on u-blox ZED-X20D
• simpleRTK3B Compass — based on Unicore UM982
• simpleRTK 4 Heading — high-performance dual-antenna option

All boards are ArduPilot & PX4 compatible and include USB + documentation.

Need help choosing the right module for your specific drone platform or payload?

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