Novatel Software Version 4.45 OM-20000026 Rev 1 RTCM Standard Logs

6 Message Formats
MiLLennium Command Descriptions Manual 39
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 messages are known as
the RTCM1 (or RTCM), RTCM3, RTCM9, and RTCM16 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
along with other NovAtel ASCII and binary data over a common communications port. As per the usual
convention, an “A” at the end of the log name denotes the NovAtel ASCII version (e.g. RTCM1A), and a “B”
denotes the NovAtel binary version (e.g. RTCM1B). These logs contain the same data that is available in the
corresponding RTCM Standard Format messages; however, the data has been “packaged” into NovAtel-format
messages.
These NovAtel-format logs are not in pure RTCM SC-104 format and are not directly usable as such. There are
two scenarios which affect how these logs are processed:
Case 1: ASCII messages (RTCMxA)
• The NovAtel header ($RTCMx) and checksum terminator (*yz) must be stripped off at the
receiving end; then, the data will need to be converted from hexadecimal to binary before
the RTCM information can be retrieved.
• Provided that the GPSCard that is acting as a remote station has its ACCEPT command set
to “ACCEPT port COMMANDS” (which is the default setting), the receiving GPSCard will
recognize the NovAtel header ($RTCMxA) as a special data input command, and apply the
differential corrections data directly. No extra processing is required.
Case 2: Binary messages (RTCMxB)
• The 12-byte NovAtel header must be stripped off before the RTCM information can be
retrieved.
• These binary messages are not presently decoded directly by GPSCards, unlike the ASCII
messages.
RTCM16T message
Syntax Range Value Description
RTCM16T - Command
message up to 90 characters ASCII text message