C Commands Summary

78 MiLLennium Command Descriptions Manual

DIFF_PROTOCOL Differential Protocol Control
NOTE: The DIFF_PROTOCOL command should only be used by advanced users of GPS.
Features:
1. A user definable key such that many different types of encoding may be used in th e same area without cross
talk between the various “channels”.
2. Encodes all correction data following any header specific to the message type.
3. Non-volatile. When the base station card is restarted, the previously selected encoding key is used for all sub-
sequent differential data.
4. The encoding key is not visible by any method of interrogation.
Syntax:
Notes: If no parameters are given to the command, the encoding type value will be reported. The key value is
not visible at anytime.
The only supported type of encoding is “Type 1”, which will only encode RTCM data with the algorithm described
below.
The non-volatility of the command is acquired via the SAVECONFIG command. This command stores the current
settings in non-volatile memory.
All header information necessary for parsing the incoming data stream remains unencoded.

RTCM/A/B LOGS

The NovAtel log format wrapping of the RTCMA and RTCMB logs remains unen coded and only the raw RTCM
data is encoded beginning after the second word of the message. This will leave the entire header unencoded:
DIFF_PROTOCOL Type Key
or DIFF_PROTOCOL DISABLE
or DIFF_PROTOCOL
Syntax Range Value Description Default
DIFF_PROTOCOL - Command
type 1, DISABLE Encoding Algorithm
key 0 - FFFFFFFF 32 Bit Encoding key
WORD 1 Preamble Message Type (Frame ID) Station ID Parity
WORD 2 Modified Z-Count Sequence No. Length of Frame Parity
REMAINING... Encoded data...