ZED-F9P-Integration Manual
UBX-18010802 - R02

3 Getting started Page 17 of 114
Advance Information
The time after which old RTCM data will be discarded can be specified using the dgnssTimeout field
in configuration item CFG-NAVSPG-CONSTR_DGNSSTO.
By default the rover will begin operation in RTK fixed mode. Upon receiving an RTCM 3x correction
stream on any of its communication interfaces, the rover will parse the data, apply the correction
and, if possible, fix ambiguities. In absence of correction data or if the correction data times out, the
rover will operate in standard GNSS mode.
The time needed to resolve the ambiguity is affected by the baseline length as well as by multipath
and satellite visibility at both rover and base station.
3.5.3 Communication interface configuration
It is possible to configure the communication interfaces of a base station or a rover. This is done
by setting the appropriate configuration items by using the CFG-UART1*, CFG-UART2*, CFG-
I2C*, CFG-SPI*, CFG-USB* configuration groups. Several configuration items allow configuring the
operation modes of the different communications interfaces. This includes parameters for the data
framing, transfer rate and protocols used. A subset of the relevant configuration items is seen below
for the UART1 only. For all available configuration items, see ZED-F9P Interface Description [2].
Configuration item Description
CFG-UART1-BAUDRATE The baud rate that should be configured on the UART1
CFG-UART1INPROT-UBX Flag to indicate if UBX should be an input protocol on UART1
CFG-UART1INPROT-NMEA Flag to indicate if NMEA should be an input protocol on UART1
CFG-UART1INPROT-RTCM3X Flag to indicate if RTCM3X should be an input protocol on UART1
CFG-UART1OUTPROT-UBX Flag to indicate if UBX should be an output protocol on UART1
CFG-UART1OUTPROT-NMEA Flag to indicate if NMEA should be an output protocol on UART1
CFG-UART1OUTPROT-RTCM3X Flag to indicate if RTCM3X should be an output protocol on UART1
Table 3: Typical configuration items used for UART1 baudrate and protocol configuration
The default communication configuration of the UART1 port is set at a baud rate of 38400
baud with NMEA messages being output. The module will respond to incoming UBX binary
commands. To see all the default configuration settings, see the u-blox ZED-F9P Interface
Description [2].
If the navigation rate of the rover is increased, the UART baud rate should be increased to
account for the additional data transferred. A baud rate of 460800 baud is recommended for
high update rates with the minimum required messages enabled.
The default baud rate of 38400 baud should be increased to allow for increased capacity over
the UART interface if UBX messages, RAW data or debug messages are enabled, again a baud
rate of 230400 baud to 460800 baud is recommended in this case.
3.5.4 Message output configuration
It is possible to configure the rate of NMEA, UBX and RTCM protocol output messages of a
base station or a rover. If the rate configuration value is zero, the corresponding message will
not be output. Values greater than zero indicate how often the message is output. Note that
all message output is additionally subject to the protocol configuration of the communication
interfaces. Messages of a given protocol will not be output until the protocol is enabled for output
on the interface.
Setting the appropriate configuration items is done by using the CFG-MSGOUT-* configuration
group. Several configuration items allow configuring the message output rates per message and
per communication interface. For all for available configuration items, see the CFG-MSGOUT-*
configuration group in ZED-F9P Interface Description [2].
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