Novatel OM-20000041 用户手册
C
Commands Summary
MiLLennium GPSCard Software Version 4.50 Command Descriptions Manual Rev 1
91
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 the same area without cross
talk between the various “channels”.
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.
sequent differential data.
4.
The encoding key is not visible by any method of interrogation.
Syntax:
NOTE:
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.
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 unencoded and only the raw RTCM
data is encoded beginning after the second word of the message. This will leave the entire header unencoded:
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...