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Document MT0605P.2018.E
© Xsens Technologies B.V.
MTi User Manual
5 Output Specification
In this chapter the various output modes of the MTi are described. The MTi’s have tens of various output
options; it is possible to select a different output frequency and/or output format (e.g. float or double) per
output or group of outputs. A full overview of outputs can be found in the [LLCP].
Performance specifications on orientation, position and sensor data can be found in section 5.3 and 5.4.
Before going into these sections, it is useful to read section 5.2, which explains the various coordinate
systems and position representations.
5.1 Overview of data outputs
The MTi supports two different data protocols: the binary (hexadecimal) XBus protocol and NMEA. Refer
to [LLCP] to learn how to switch between data protocols.
5.1.1 MTData2 output in XBus protocol
The [LLCP] contains a full list of all data outputs. Refer to the table in the MTData2 message description.
5.1.2 ASCII output (NMEA)
The MTi also supports a variety of strings in ASCII, amongst others messages in the NMEA protocol.
The list of available ASCII strings can be found in the [LLCP], in the table in the description of the
SetStringOutputType message.
5.2 Coordinate systems
Data from the MTi is represented in various coordinate systems, which are explained below.
5.2.1 Calibrated inertial data and magnetic field data
The
sensor coordinate system (S)
is a right-handed coordinate Cartesian system that is body-fixed to
the device. It is possible to rotate the sensor coordinate system to an
object coordinate system (O)
when the MTi is not exactly aligned with the axes of the object or vehicle the MTi is attached to. See
section 5.9 for more information on alignment matrices.
(S) and (O, when applied) are used in the rate-of-turn (DataID 0x8020), acceleration (DataID 0x4020)
and magnetic field (DataID 0xC020) outputs. The encased version of the MTi shows the coordinate
system on the sticker. Depicted below is the sensor coordinate system on the encased MTi and the
OEM version. Small x, y and z are used for
(S)
and the object coordinate system
(O)
. Capital X, Y and
Z are
generally
, but not always, used for velocity. They stand for the local-earth fixed coordinate system
(L)
, see section 5.2.3.
