General Information

• Ordering information
• MTi 600-series architecture
• MTi 600-series product variants
  • MTi-610 IMU
  • MTi-620 VRU/AHT
  • MTi-630(R) AHRS
  • MTi-670(G) GNSS/INS
  • MTi-680(G) RTK GNSS/INS

This document provides information on the usage and technical details of the MTi 600-series. The MTi 600-series module (MTi-600) is a fully functional, self-contained module that is easy to design-in. The MTi-600 module (IP51) can be connected to a host through RS232, CAN or UART interfaces, or through USB using the UART to USB converter (included in the MTi 600-series Development Kit). In contrast, the MTi 600-series robust trackers (MTi-630R, MTi-670G and MTi-680G) are rugged (IP68) devices which can be connected to a host through RS232 or CAN interface, or through USB using the RS232 to USB converter dongle (included in the MTi 600-series Starter Kit).

The Family Reference Manual supplements this document. It reports generic information on the MTi 1-series and MTi 600-series, such as output definitions, algorithm details and installation tips.

The MTi 600-series Hardware Integration Manual supplements this document. In this document, notes on typical application scenarios, printed circuit board (PCB) layout, origin of measurement reference system, stress related considerations, reference designs and handling information can be found.

For testing and prototyping, Xsens provides the MTi-630, MTi-670 and MTi-680 Development Kits (MTi-630-DK, MTi-670-DK and MTi-680-DK) as well as Starter Kits (SK) for the robust MTi-630R, MTi-670G and MTi-680G. In addition to the RS232, CAN and UART pin connectors of the MTi 600-series module, the Development Kit offers a direct USB, RS232, RS422 and CAN interface. Technical details of the Development Kit and its usage can be found in the MTi 600-series DK User Manual.

The MT Low Level Communication Protocol document provides a complete reference for the protocols used to communicate with Xsens Motion Trackers on a low-level basis. The MT Low Level Communication Protocol document also describes the synchronization messages and settings in detail.

Ordering information

MTi 600-series architecture

MTi 600-series module diagram

The diagram in the figure above shows a simplified architecture of the MTi 6x0-series module. The MTi-6x0 contains a 3-axis gyroscope, 3-axis accelerometer, 3-axis magnetometer, barometer, a high-accuracy crystal and a low-power micro-controller unit (MCU). The MTi-670/680 module can also accept signals from an external GNSS receiver. The MCU coordinates the timing and synchronization of the various sensors. The module offers the possibility to use external signals in order to accurately synchronize the clock and/or outputs of the MTi-6x0 with any user application. The MCU applies calibration models (unique to each sensor and including orientation, gain and bias offsets, plus more advanced relationships such as non-linear temperature effects and other higher order terms) and runs the Xsens optimized strapdown algorithm, which performs high-rate dead-reckoning calculations up to 2 kHz, allowing accurate capture of high frequency motions and coning & sculling compensation. The Xsens sensor fusion engine combines all sensor inputs and optimally estimates the orientation, position and velocity at an output data rate of up to 400 Hz. The output data of the MTi-600 is easily configured and customized for an application’s needs and can be set to use one of various filter profiles available within the Xsens sensor fusion engine. In this way, the MTi-600 limits the load and the power consumption on the user application’s processor. The user can communicate with the module by means of three different communication interfaces; RS232, CAN and UART[1]. Other interfaces are available using an MTi Development Kit or by using third party equipment (e.g. UART/RS232 to USB converter). 

Contrary to the above image, the robust MTi-670G and MTi-680G include an internal GNSS receiver.

MTi 600-series product variants

The MTi-6x0 module is a fully tested self-contained module available as an:

• Inertial Measurement Unit (IMU),
• Vertical Reference Unit (VRU) / Active Heading Tracker (AHT),
• Attitude and Heading Reference System (AHRS)
• GNSS aided Inertial Navigation System (GNSS/INS).

It can output 3D orientation data (Euler angles, rotation matrix or quaternions), orientation and velocity increments (∆q and ∆v), position and velocity quantities and calibrated sensor data (acceleration, rate of turn, magnetic field and pressure). Depending on the product variant, output options may differ.

MTi-610 IMU

The MTi-610 module is an IMU that outputs calibrated 3D rate of turn, 3D acceleration, 3D magnetic field and barometric pressure. The MTi-610 also outputs coning and sculling compensated orientation increments and velocity increments (∆q and ∆v). Advantages over a simple gyroscope-accelerometer combo-sensor are the inclusion of synchronized magnetic field and barometric data, on-board signal processing and the easy-to-use synchronization and communication protocol. The signal processing pipeline and the suite of output options allow access to the highest possible accuracy at any output data rate up to 2000 Hz. Moreover, the testing and calibration is already performed by Xsens and results in a robust and reliable sensor module, which enables a short time to market for the users.

MTi-620 VRU/AHT

The MTi-620 is a 3D VRU/AHT. On top of the functionality of the MTi-610 IMU, its algorithm computes 3D orientation data with respect to a gravity referenced frame: drift-free roll, pitch and unreferenced yaw. Although the yaw is unreferenced, it is superior to only gyroscope integration as a result of advanced on-board sensor fusion. The 3D acceleration is also available as so-called free acceleration, which has the local-gravity subtracted. The drift in unreferenced heading can be limited by using the Active Heading Stabilization (AHS) functionality. See Signal processing and algorithms  for more details. The raw sensor signals are combined and processed at a high frequency to produce a real-time data stream with the device’s 3D orientation (roll, pitch and yaw) up to 400 Hz.

MTi-630(R) AHRS

The MTi-630 supports all features of the MTi-610 and MTi-620, and, in addition, is a full magnetometer-enhanced AHRS. In addition to the roll and pitch, it outputs a yaw (heading) output that is referenced to the Earth's magnetic field and calibrated sensor data: 3D acceleration, 3D rate of turn, 3D orientation and velocity increments (∆q and ∆v) and 3D magnetic field data. The raw sensor signals are combined and processed at a high frequency to produce a real-time data stream with the device’s 3D orientation (roll, pitch and yaw) up to 400 Hz.

In contrast to the MTi-630, the MTi-630R comes as a robust (IP68) module.

MTi-670(G) GNSS/INS

The MTi-670 provides a GNSS/INS solution offering a position and velocity output in addition to orientation estimates. The MTi-670 uses advanced sensor fusion algorithms developed by Xsens to synchronize the inputs from the module’s on-board gyroscope, accelerometer, magnetometer and barometer, with the data from an external GNSS receiver. The raw sensor signals are combined and processed at a high frequency to produce a real-time data stream with the device’s 3D position, velocity and orientation (roll, pitch and yaw) up to 400 Hz.

In contrast to the MTi-670, the MTi-670G comes as a robust (IP68) module with an integrated GNSS receiver.

MTi-680(G) RTK GNSS/INS

The MTi-680 provides a GNSS/INS solution offering a centimeter-accurate position and velocity output in addition to orientation estimates. The MTi-680 uses advanced sensor fusion algorithms developed by Xsens to synchronize the inputs from the module’s on-board gyroscope, accelerometer, magnetometer and barometer, with the data from an external, RTK-enabled GNSS receiver. The raw sensor signals are combined and processed at a high frequency to produce a real-time data stream with the device’s 3D position, velocity and orientation (roll, pitch and yaw) up to 400 Hz.

In contrast to the MTi-680, the MTi-680G is a robust tracker that uses an internal L1/L2 RTK enabled GNSS receiver.

[1] The UART port is not available on robust trackers (MTi-630R, MTi-670G, MTi-680G).