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UM4B0 is an all-constellation all-frequency RTK positioning module based on the high-performance high-precision SoC - NebulasII, which is developed by Unicore Communications. It supports multiple satellite signals, including BDS B1I/B2I/B3I/B1C/B2a, GPS L1/L2/L5, GLONASS L1/L2, Galileo E1/E5a/E5b and QZSS L1/L2/L5. UM4B0 has adopted narrowband anti-jamming technology. It is mainly applied in the field of light-weight robots, GIS, intelligent driving, UAV,etc.


Product Features

  • Based on multi-system multi-frequency high-performance SoC - NebulasII, with 432 super channels

  • Support BDS, GPS, GLONASS, Galileo and QZSS, including Beidou-3 signal 

  • 30x40 mm, small size all-system all-frequency RTK positioning SMD module

  • Instantaneous RTK initialization and support long baseline RTK solution

  • Adaptive recognition of differential data RTCM format, support antenna signal detection

  • 60dB narrowband anti-jamming, support multi-path suppression technology

  • Support UART, 1PPS, Event and other physical interfaces

Great Performance comes in different sizes

  • Compact SMD packaging

  • All-Constellation Multi-Frequency 

Customized services

  • Firmware quick update and iteration

  • Rich and Flexible Evaluation Kits and Softwares

  • Proven - Products have been widely applied in worldwide projects, a leading choice for Intelligent Drive, Robots, UAV,etc

Core Technology

  • "UGypsophila" RTK technology

  • Better than 1s RTK reacquisition

  • "RTKKEEP" Technology 

  • Adaptive recognition of RTCM

Technical Specifications

Performance Specifications

Channels432 channels,based on Nebulas-II chipObservation Accuracy(RMS)BDSGPSGLONASSGalileo
FrequencyBDS B1/B2/B3B1/L1(C/A)/E1 Code10cm10cm10cm10cm
GPS L1/L2/L5B1/L1/E1 Carrier Phase1mm1mm1mm1mm
GLONASS L1/L2B2/L2P(Y)/L2C/E5b Code10cm10cm10cm10cm
Galileo E1/E5a/E5b
B2/L2p(Y)/L2C/E5b Carrier Phase1mm1mm1mm1mm
GLONASS L1/L2B2/L2P(Y)/L2C/E5b Code10cm10cm10cm10cm
B3/L5/E5a Carrier Phase1mm1mm1mm1mm
Single point positioningHorizontal:1.5 mInitialization time< 5 s (typical)
Vertical:2.5 mInitialization reliability> 99.9%
DGPS(RMS)Horizontal:0.4 mReacquisition< 1 s
Vertical:0.8 mCorrectionRTCM v2.3/3.0/3.2
RTK(RMS)Horizontal:10 mm + 1 ppmData OutputNMEA-0183,Unicore Binary
Vertical:15 mm + 1 ppmUpdate Rate20 Hz
Velocity Accuracy (RMS)0.03 m/sPositioning rate20 Hz
Time to First Fix (TTFF)Cold start < 25 sTime accuracy (RMS)20 ns
Hot start < 10 sDead Reckoning Error<5% of distance travelled during GPS denied conditions

Network ProtocolNTRIP、TCP/IP

Physical Specifications


30 × 40 × 4 mm


9.2 g

Functional Ports



1xEvent input

Environmental Specifications


Working: -40℃~+85℃

Storage: -55℃~+95℃


95% No condensation





Electrical Specifications


3.3 VDC +5%/–3%


4.75~5.0 V, 0~100 mA

Ripple Voltage

100 mV p-p(max)

Power Consumption

1.8 W (typical)


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