Trimble Outdoors SK8 - Manual (Page 158)

C-12 Lassen-SK8 Embedded GPS Module
Trimble ASCII Interface Protocol (TAIP)
C.10 DC Differential Corrections
The DC message provides the sensor with differential corrections from type-1 and type-9
RTCM-104 records. The numerical are written out in hex format producing a two digit
hex number for each data byte.
Data String Format:
AAAABBCC{DDEEEEFFGG}
Table C-10. Delta Differential Corrections Data String Descriptions
Units and scale factors are defined by RTCM-104, version 2. The SV PRN and scale factor
contains the SV PRN in the lower 5 bits and the scale factor in the higher 3 bits. The scale
factor has only three acceptable values:
• 0 - Use with low scale factor
• 4 - Use with high scale factor
• 7 - Do not use
Range corrections are scaled by 0.02 meters for low scale factor and 0.32 m/sec for high
scale factor.
*
Note – DC and DD TAIP messages are used to enclose differential corrections within the
TAIP format.
*
Note – DC and DD messages used to input corrections require only one communications
channel. When the auxiliary port is used to input RTCM 104 corrections, it assumes a
separate communications channel is available for broadcast and receipt of differential
corrections.
*
Note – The TAIP Software Toolkit does not support DC and DD messages.
Item # of Char Type UNITS Format
Modified Z-count 4 WORD .6 sec AAAA
Station health 2 BYTE N/A BB
Number of SVs 2 BYTE N/A CC
The next five bytes (10 characters) are repeated for each SV.
SV PRN & scale factor 2 BYTE n/a DD
Range correction 4 WORD RTCM-104 EEEE
Range-rate correction 2 BYTE RTCM-104 FF
IODE 2 BYTE n/a GG