Datasheet

NEO-M8U - Data Sheet
UBX-15015679 - R06 Functional description Page 11 of 27
Product Information
1.10 Odometer
The odometer provides information on travelled ground distance (in meter) using position and velocity
measurements from the combined GNSS/DR navigation solution. For each computed travelled
distance since the last odometer reset, the odometer estimates a 1-sigma accuracy value. The total
cumulative ground distance is maintained and saved in the BBR memory.
☞ The odometer feature is disabled by default.
1.11 Data logging
The u-blox NEO-M8U receiver can be used in data logging applications. The data logging feature
enables continuous storage of position, velocity and time information to an onboard SQI flash
memory. It can also log the distance reported by the odometer. The information can be downloaded
from the receiver later for further analysis or for conversion to a mapping tool.
1.12 Geofencing
The u-blox NEO-M8U module supports up to four circular geofencing areas defined on the Earth’s
surface using a 2D model. Geofencing is active when at least one geofence is defined, the current
status can be found by polling the receiver. A GPIO pin can be nominated to indicate status to e.g.
wake up a host on activation.
1.13 Message Integrity Protection
The NEO-M8U provides a function to detect third party interference with the UBX message stream
sent from receiver to host. The security mechanism “signs” nominated messages via a subsequent
UBX message. This message signature is then compared with a signature generated by the host to
determine if the message data has been altered.
1.14 Spoofing Detection
Spoofing is when a malicious third party tries to control the reported position via a fake GNSS
broadcast signal. This may result in reporting incorrect position, velocity or time. To combat this, the
NEO-M8U module includes spoofing detection measures to alert the host when signals appear to be
suspicious. The receiver combines a number of checks on the received signals looking for
inconsistencies across several parameters.
1.15 TIMEPULSE
A configurable time pulse signal is available with the NEO-M8U module.
The TIMEPULSE output generates pulse trains synchronized with GPS or UTC time grid with intervals
configurable over a wide frequency range. Thus it may be used as a low frequency time
synchronization pulse or as a high frequency reference signal.
☞ The NEO-M8U time-pulse output is configured using messages for “TIMEPULSE2.” This pin has a
secondary function during start-up (initiation of “SAFEBOOT” mode for firmware recovery) and
should not normally be held LOW during start-up.
By default the time pulse signal is disabled.