UM981

UM981
GPS/BDS/GLONASS/Galileo/QZSS All-constellation Multi-frequency RTK/INS
Integrated Positioning Module
Unicore's new-generation proprietary RTK/INS integrated navigation module. The
module integrates a high-speed floating-point processor and an RTK-dedicated
coprocessor, enabling it to output IMU raw data at 100Hz and RTK data at 50Hz,
respectively. The on-board MEMS chip and algorithm ensure continuous, high-
quality positioning results in GNSS denied environments such as buildings,
tunnels, overpasses, and shaded areas. With its high precision and performance,
the UM981 is well-suited for surveying and precision agriculture, among other
applications.

Features
Based on the new generation GNSS SoC - NebulasIV, which integrates RF,
baseband, and high precision algorithm

All-constellation multi-frequency RTK engine and advanced RTK technology

Instant RTK initialization technology

60 dB narrowband interference suppression and interference detection

Heading2 technology to provide orientation information

STANDALONE single-station high-precision positioning technology

Supports B2b-PPP and E6-HAS

On-board MEMS integrated navigation and U-Fusion technology to ensure
continuous positioning when loss of lock on GNSS signals

Technical Specifications
Performance Specifications
Channel 1408 channels, based on NebulasIV
Frequency GPS L1C/A, L1C, L2C, L2P(Y), L5
BDS B1I, B2I, B3I, B1C, B2a, B2b
GLONASS G1, G2, G3
Galileo E1, E5a, E5b, E6
QZSS L1C/A, L1C, L2C, L5
NavIC L5
SBAS L1C/A
Single Point Positioning(RMS) Horizontal: 1.5m
Vertical: 2.5m
DGPS (RMS) Horizontal: 0.4m
Vertical: 0.8m
RTK (RMS) Horizontal: 0.8cm+1ppm
Vertical: 1.5cm+1ppm
PPP（RMS）  Horizontal: 5cm
Vertical: 10 cm
Tilt Measurement 10 mm + 0.7 mm/°tilt 
(accuracy < 2.5 cm within 30°)
Positioning Error of INS only < 5 % of the distance traveled without GNSS
signals
Observation Accuracy (RMS) BDS GPS GLONASS Galileo
B1I/B1C/L1 C/A/G1/E1 Code 10 cm 10 cm 10 cm 10 cm
B1I/B1C/L1C/A/G1/E1 Carrier Phase 1 mm 1 mm 1 mm 1 mm
B2I/B2a/B2b/L5/E5a/E5b Code 10 cm 10 cm 10 cm 10 cm
B2I/L2P(Y)/L2C/G2/E5b Carrier Phase 1 mm 1 mm 1 mm 1 mm
B3I/B2a/E5a/L5 Code 10 cm 10 cm 10 cm 10 cm
B3I/B2a/E5a/L5 Carrier Phase 1 mm 1 mm 1 mm 1 mm
Time Accuracy (RMS) 20 ns
Velocity Accuracy (RMS) 0.03 m/s
Cold start < 12 s
Initialization Time < 5 s (typical)
Initialization Reliability > 99.9%
Data Update Rate 100 Hz (IMU RAW Data)
50 Hz* (RTK)
Differential Data RTCM V3.X
Data Format NMEA-0183, Unicore

Physical Characteristics
Packaging 54 pin LGA
Dimension 17.0 × 22.0 × 2.6 mm
Weight 1.91 g ± 0.03 g

Environmental Specifications
Working temperature -40 °C ~ +85 °C
Storage Temperature -55 °C ~ +95 °C
Humidity 95% No condensation
Vibration GJB150.16A-2009, MIL-STD-810F
Shock GJB150.18A-2009, MIL-STD-810F

Communication Interface
3 x UART (LVTTL)
1 x I2C*
1 x SPI*
1 × CAN* (shared with UART3)

Note: Items marked with * are only supported by specific firmware.

For more information about unicore communications and anti-jamming, please feel
free to contact us!

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