NEO-M8U - Hardware Integration Manual
UBX-15016700 - R07
Untethered Dead Reckoning
Page 15 of 28
Production Information
3
Untethered Dead Reckoning
3.1
Implementation
The NEO-M8U 3D Untethered Dead Reckoning module makes use of GNSS and internal gyroscope
and accelerometer sensors only with no need or provision for speed pulse or forward/reverse
information.
3.2
Installation
In order to achieve good performance, the NEO-M8U hardware needs to be mounted in the vehicle in
such a way that its alignment is stable to within 2°. It is important that the mounting design minimizes
vibration and mechanical resonance.
Figure 10: NEO-M8U with IMU sensor frame
3.3
Initialization and Calibration
The benefits of dead reckoning are available once the receiver has completed its initialization phase
following installation. Initialization parameter values are subsequently stored in the battery-backed
RAM (BBR) for immediate use, and may also be saved in Flash memory. The duration of the
initialization depends on the quality of the GNSS signals as well as the dynamics encountered by the
vehicle.
For details on Initialization and calibration, see the
u-blox 8 / u-blox M8 Receiver Description Including
Protocol Specification [2].
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Note that the performance of the UDR solution relies on a stable sensor location and orientation
with respect to the vehicle frame. The module must be mounted securely within the vehicle.
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To read more about mandatory and optional configuration parameters, see the UDR configuration
section of
u-blox 8 / u-blox M8 Receiver Description Including Protocol Specification [2].
