4 Message Formats
50 MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2
RTCM Standard Commands

RTCMRULE

The RTCM standard states that all equipment shall support the use of the "6 of 8" format (data bits a1 through a6
where bits a1 through a6 are valid data bits and bit a7 is set to mark and bit a8 is set to space).
The GPSCard RTCMRULE command allows for flexibility in the use of the bit rule to accommodate compatibility
with equipment that does not strictly adhere to the RTCM stated rule.
Syntax:
Example:
rtcmrule 6cr

RTCM16T

This is a NovAtel GPSCard command which relates to the RTCM Type 16
This command allows the GPSCard user to set an ASCII text string. Once set, the text string can be transmitted as
standard format RTCM Type 16 data (see the RTCM16 log, Page 54). The text string entered is limited to a
maximum of 90 ASCII characters. This message is useful for a reference station wanting to transmit special
messages to remote users.
The text string set here can be verified by observing the RCCA command configuration log. As well, the message
text can be transmitted as a NovAtel Format ASCII log by utilizing the "LOG port RTCM16T" command.
Syntax:
Example:
rtcm16t This is a test of the RTCM16T Special Message.
RTCM Standard Logs
The NovAtel logs which implement the RTCM Standard Format for Type 1, 3, 9, and 16, 18, 19 and 22 messages
are known as the RTCM1 (or RTCM), RTCM3, RTCM9, RTCM16, RTCM1819 and RTCM22 logs, respectively,
while Type 59N-0 messages are listed in the RTCM59 log.
NovAtel has created ASCII and binary versions of each of these logs so that RTCM data can be sent or received
RTCMRULE rule
Syntax Range Value Description Default
RTCMRULE -Command
rule 6CR 6CR is for 6 bits of valid data per byte. Each frame is followed by a <CR> character. 6CR
6SP 6SP (6 bit special); the RTCM decoder of the remote receiver will ignore the two MSB of the
data and hence all 6 bit data will be accepted. This allows users with non-conforming 6 bit rule
data to use the NovAtel receiver to accept their RTCM data. The user will not be allowed to
enter extra control data such as CR/LF, as this will be treated as RTCM data and cause the
parity to fail. This option does not affect RTCM generation. The output will be exactly the same
as if the RTCMRULE 6 option was chosen. The upper two bits are always encoded as per
RTCM specification.
66 is for 6 bits of valid data per byte
88 is for 8 bits of valid data per byte
RTCM16T message
Syntax Range Value Description
RTCM16T -Command
message up to 90 characters ASCII text message