CAM-M8 - Data Sheet

UBX-15031574 - R04

Page 11 of 31

Production Information

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

Differential GPS Corrections

2

Delta Differential GPS Corrections

3

GPS Reference Station Parameters

9

GPS Partial Correction Set

Table 3: Supported RTCM 2.3 messages

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.

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