CAM-M8 - Data Sheet
1.7.4 Differential GPS (D-GPS)
The u-blox CAM-M8 series receivers support differential GPS data according to RTCM 10402.3 [4].
The use of differential GPS data improves GPS position accuracy. The RTCM implementation
supports the following RTCM 2.3 messages:
Message Type
Description
1
2
3
9
Differential GPS Corrections
Delta Differential GPS Corrections
GPS Reference Station Parameters
GPS Partial Correction Set
Table 3: Supported RTCM 2.3 messages
☞
RTCM corrections cannot be used together with SBAS.
☞
For more details, see the u-blox 8 / u-blox M8 Receiver Description Including Protocol
Specification [2].
1.8 Broadcast navigation data and satellite signal
measurements
The CAM-M8 series modules can output all the GNSS broadcast data upon reception from tracked
satellites. This includes all the supported GNSS signals plus the augmentation services SBAS, QZSS
and IMES. The receiver also makes available the tracked satellite signal information, i.e. raw code
phase and Doppler measurements in a form aligned to the ETSI mobile cellular location services
protocol (RRLP) [6]. For more details, see the u-blox 8 / u-blox M8 Receiver Description Including
Protocol Specification [2].
1.9 Odometer
The odometer provides information on travelled ground distance (in meters) using solely the position
and Doppler-based velocity of the 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. For more details, see the u-blox 8 / u-blox M8
Receiver Description Including Protocol Specification [2].
1.10 Geofencing
The CAM-M8 series modules support up to four circular Geofencing areas defined on the Earth’s
surface using a 2D model. Geofencing is active when at least one Geo-fence 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.
1.11 Message Integrity Protection
The CAM-M8 modules provide a function to detect third party interference with the UBX message
steam sent from receiver to host. The security mechanism “signs” nominated messages via a
subsequent UBX message. This message signature is then compared with one generated by the host
to determine if the message data has been altered. The signature algorithm seed can use one fixed
UBX-15031574 - R04
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