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By WitMotion

RTK GNSS/INS Module UM982/UM980 Centimeter-level Positioning and Orientation

$10.80 - $415.62
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WTRTK - M20 - Accelerometer+Inclinometer - mpu6050 - mpu9250+Angle Sensor Gyroscope for Arduino Magneometer.
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inertial measurement unit
inertial measurement unit

Product Description

The WTRTK series delivers cm-level RTK positioning with full-constellation support (BDS/GPS/GLONASS/Galileo/QZSS). It offers 3 tailored models: WTRTK-982 for dual-antenna 0.1° heading, WTRTK-980 for 50Hz high-speed tracking, and WTRTK-960 for stable 20Hz positioning. Featuring anti-jamming RF, fast acquisition, Type-C/UART/PPS interfaces, and UPrecise software/ROS support, it’s perfect for UAVs, robotics, and smart agriculture

产品1

Centimeter-Level RTK

RTK FIX eliminates position drift and ensures clear, true-to-path trajectory tracking. Precision: 0.8cm (H) +1ppm / 1.5cm (V) +1ppm. Perfect for highly accurate surveying, navigation, and automated control systems.

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Dual-Antenna Heading

Uses master and slave antennas to form a 1m baseline, delivering stable heading and pitch angles with 0.1° accuracy. Optimized for precise orientation in vehicles, UAVs, robots, and agricultural machinery (supported exclusively by WTRTK-982).

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50Ω RF Matching

Full π-type antenna matching with VSWR <1.8. Minimizes reflection loss, delivering highly stable GNSS signal reception for reliable RTK accuracy.

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Fast RTK Fix

Rapid satellite acquisition achieves RTK FIX in <10s. Supports up to 50Hz refresh rate, greatly reducing field wait time and boosting operational efficiency.

inertial measurement unit

RTK Differential Positioning Principle

RTK (Real-Time Kinematic) differential positioning is a high-precision GNSS technology that relies on a fixed base station and a mobile rover to achieve centimeter-level accuracy. The base station, located at a known surveyed coordinate, continuously tracks satellite signals and calculates real-time positioning errors, then broadcasts RTCM correction data to the rover via a radio or cellular data link. The rover combines these differential corrections with its own observations to effectively eliminate common errors caused by ionospheric and tropospheric delays, satellite clock biases, and orbital inaccuracies. By resolving carrier-phase integer ambiguities, the system rapidly transitions from standard meter-level single-point positioning to an RTK FIX state, delivering instant cm-level accuracy (0.8cm + 1ppm) and enabling fast convergence (<10s). This highly stable and real-time technique forms the essential foundation for precise trajectory tracking, autonomous navigation, and smart control in applications like UAVs, robotics, and automated agricultural machinery.

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ENIG Finish

Reliable soldering and stable long-term contact

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Precision PCB

Compact routing and tidy layout, ideal for embedded integration

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Thermal Design

Auxiliary structure to assist heat conduction and ensure stable operation

inertial measurement unit

Application Scenarios

应用场景1

01 Precision Agriculture & Tractor Auto-Steering

Our RTK module acts as the core navigation engine for tractors, seeders, and sprayers. It provides centimeter-level real-time positioning to ensure precise straight-line driving, significantly reducing seed/chemical overlap and missed coverage during high-efficiency farming operations.

应用场景2

02 Outdoor Robot Navigation & Autonomous Tracking

For outdoor inspection robots and robotic lawnmowers, our high-precision module delivers stable heading and position data. It powers accurate path tracking and fully autonomous navigation, ensuring reliable operational stability even in complex outdoor terrains.

应用场景3

03 UAV Aerial Surveying & Photogrammetry

Our module facilitates high-accuracy flight control for UAVs. By providing centimeter-level coordinates and precise directional data, it ensures accurate route planning, oblique photography execution, and high-fidelity 3D modeling for professional aerial mapping and surveying

应用场景4

04 Construction Machinery Guidance & Heavy Equipment Control

Integrated into excavators, bulldozers, and graders, our module provides real-time location monitoring and precise guidance. This empowers operators to control heavy equipment accurately, enhancing construction site management and significantly boosting project scheduling efficiency.

应用场景5

05 Engineering Staking & Surveying Measurement

Used for road, bridge, and pipeline engineering staking, our module delivers high-precision coordinate acquisition and fast stakeout capability. It helps surveyors achieve rapid point location and accurate measurement verification, ensuring strict alignment with engineering design

应用场景6

06 Vehicle Mobile Mapping & Spatial Data Collection

Serving as the primary positioning sensor in mobile mapping vehicles, our module works in synergy with posture fusion algorithms. It ensures accurate track recording and precise spatial data collection, which is essential for road mapping and comprehensive urban environment

应用场景7

07 Unmanned Surface Vessel (USV) Hydrographic Surveying

Our RTK module enables centimeter-level positioning and reliable course control for unmanned boats. It guarantees stable autonomous cruise and accurate water depth mapping in rivers, lakes, and reservoirs, dramatically improving the efficiency of aquatic surveying tasks.

Product WTRTK-982
Chip UM982
Channels 1408
Antenna Dual-Antenna Positioning & Heading
Output Rate 20Hz (Dual-Antenna)
Signal Reception BDS B1I, B2I, B3I; GPS L1C/A, L2C, L2P(Y), L5; GLONASS G1, G2; Galileo E1, E5a, E5b; QZSS L1C/A, L2C, L5; SBAS L1C/A
Cold Start TTFF ≤30s
Hot Start TTFF ≤1s
Positioning Accuracy Single Point Positioning: 1.5m horizontal, 2.5m vertical; Differential Positioning: 0.4m+1ppm horizontal, 0.8m+1ppm vertical; RTK GNSS: 0.8cm+1ppm horizontal, 1.5cm+1ppm vertical
Heading Accuracy 0.1°/1m baseline
Time Accuracy 20ns
Velocity Accuracy 0.03m/s
Serial Port Baud Rate range 4800~921600 bps, default 115200 bps, 8 data bits, no parity, 1 stop bit
Protocol NMEA0183
Operating Voltage 3.4V~5V (recommended 3.7V)
Power Consumption 220mA @ 5V
Operating Temperature 65°C
Storage Temperature -45~125°C
Dimensions 26.0×38×7.6mm
Product WTRTK-980
Chip UM980
Channels 1408
Antenna Single-Antenna Positioning
Output Rate 50Hz (Single-Antenna)
Signal Reception BDS B1I, B2I, B3I; GPS L1C/A, L1C, B2a, B2b; GLONASS G1, G2, G3; Galileo E1, E5a, E5b, E6; QZSS L1C/A, L1C, L2C, L5; NavIC L5; SBAS L1C/A
Cold Start TTFF <12s
Hot Start TTFF <4s
Positioning Accuracy Single Point Positioning: 1.5m horizontal, 2.5m vertical; Differential Positioning: 0.4m+1ppm horizontal, 0.8m+1ppm vertical; RTK GNSS: 0.8cm+1ppm horizontal, 1.5cm+1ppm vertical
Heading Accuracy Not applicable
Time Accuracy 20ns
Velocity Accuracy 0.03m/s
Serial Port Baud Rate default 115200 bps, 8 data bits, no parity, 1 stop bit
Protocol NMEA0183
Operating Voltage 3.4V~5V (recommended 3.7V)
Power Consumption 220mA @ 5V
Operating Temperature 85°C
Storage Temperature -45~125°C
Dimensions 26.0×38×7.6mm
Product WTRTK-960
Chip UM960
Channels 1408
Antenna Single-Antenna Positioning
Output Rate 20Hz (Single-Antenna)
Signal Reception BDS B1I, B2I, B3I; GPS L1C/A, L2C, L2P(Y), L5; GLONASS G1, G2; Galileo E1, E5a, E5b; QZSS L1C/A, L2C, L5; SBAS L1C/A
Cold Start TTFF ≤30s
Hot Start TTFF <5s
Positioning Accuracy Single Point Positioning: 1.5m horizontal, 2.5m vertical; Differential Positioning: 0.4m+1ppm horizontal, 0.8m+1ppm vertical; RTK GNSS: 0.8cm+1ppm horizontal, 1.5cm+1ppm vertical
Heading Accuracy Not applicable
Time Accuracy 20ns
Velocity Accuracy 0.03m/s
Serial Port Baud Rate range 4800~921600 bps, default 115200 bps, 8 data bits, no parity, 1 stop bit
Protocol NMEA0183
Operating Voltage 3.4V~5V (recommended 3.7V)
Power Consumption 158mA @ 5V
Operating Temperature 85°C
Storage Temperature -45~125°C
Dimensions 26.0×38×7.6mm

Technical Documentation

Click "View" to open the document in WitMotion Drive.

Universal Software & Drivers
View
WTRTK PC Software
View
WTRTK-982_User Manual_EN_R1.3
View
WTRTK-982 Product Specification
View
WTRTK-980 configuration steps for base station and mobile station
View
Unicore Reference Commands Manual For N4 High Precision Products_V2_EN_R1.2
View
GNSS antenna datasheet
View
3.22WTRTK-982 Application Video
View
WTKRTK-982 SDK User Manual
View
STM32Core_UM982
View
ROS_RTK
View
Ntrip2Uart (3)
View
WTRTK-980 Product Specification
View
UM980_User Manual_EN_R1.4
View
WTRTK-960 Product Specification
View
UM960_User Manual_EN_R1.0
View
WTRTK-LET Board
View
What is the difference between Active Antenna and Passive Antenna?

All our antennas are Active Antenna.

A Passive Antenna does not contain any active electronic components.

An Active Antenna integrates a signal amplifier behind the passive antenna to improve signal strength.

Passive Antenna does not require power feeding; Active Antenna requires power feeding.

What is PPP?

PPP stands for Precise Point Positioning. It uses predicted or post-mission precise GPS satellite ephemeris as the known coordinate starting data. The basic principle is similar to standard GPS single-point positioning, but the difference lies in the precision.

To achieve high precision, PPP has the following characteristics:

a. PPP provides absolute positioning, unlike RTK GNSS which provides relative positions relative to a reference station.

b. PPP does not use differential technology. Instead, it constructs ionosphere-free pseudorange and carrier-phase combinations using dual-frequency or multi-frequency receivers to eliminate the first-order ionospheric effects.

c. PPP uses precise ephemeris and precise satellite clock data. PPP is also affected by satellite visibility. If the user cannot track the required satellites, even the most accurate orbit and clock data cannot be used. When satellites from one system are not visible, using satellites from other GNSS systems ensures the best possible service.

d. PPP Accuracy: 10cm horizontal, 20cm vertical. Longer observation times result in higher accuracy.

Note: Only WTRTK-980 and WTRTK-982 support PPP.

What is the difference between Single-Frequency, Dual-Frequency, Triple-Frequency, and Multi-Frequency?

Single-Frequency means the GNSS receiver operates on a single frequency band, typically L1.

Dual-Frequency means the GNSS receiver operates on two frequency bands, typically L1/L2 or L1/L5. It can cancel the majority of the ionospheric error using observations from both frequencies.

Triple-Frequency means the GNSS receiver operates on three frequency bands, typically L1/L2/L5.

Multi-Frequency means the GNSS receiver operates on multiple frequency bands, such as L1/L2/L5/L6. Generally, multi-frequency GNSS receivers offer higher signal acquisition sensitivity, stronger anti-interference capabilities, and higher positioning accuracy compared to single-frequency receivers.

What do Cold Start, Warm Start, and Hot Start mean?

Cold Start: The receiver starts up with no known ephemeris, almanac, approximate time, or approximate position.

Warm Start: The receiver starts up with known almanac, approximate time, and approximate position, but unknown ephemeris.

Hot Start: The receiver starts up with known ephemeris, almanac, approximate time, and approximate position.

What does "Heading" mean in Positioning & Heading?

It refers to the baseline vector formed between the primary antenna and the secondary antenna of the dual-antenna receiver. The Heading is defined as the counterclockwise angle between this baseline vector and true north.

Does the product have an internal IMU? Can it still output Heading without longitude and latitude?

The product does not have an internal IMU. Both Positioning and Heading are calculated based on longitude and latitude.

If longitude and latitude are unavailable, the Heading function cannot be used.

However, you can refer to our RTK-4GA product, which integrates an IMU and can still function without longitude and latitude data.

When one Base Station connects to multiple Rover Stations, how to distinguish each Rover?

The Base Station transmits differential data containing the Base Station ID. Each Rover can be distinguished by its module version information.

Example:

  1. Query version: VERSIONA
  2. The returned version information is as follows:
    #VERSIONA,98,GPS,UNKNOWN,1,100000,0,0
    18,54:"UM982""R4.10Build11826""HRPTO0-S10C-p""2310415000012-LR23A2233111486"ff3b65918f09978e"2023/11/24"*9ca48213
  3. The string LR23A2233111486 is the unique module identifier.