DR + GPS
STARTER KIT REFERENCE MANUAL
Lassen DR + GPS Reference Manual 93
The DR calibration messages contain the current settings for the gyro and tacho
parameters. They are typically transmitted when the parameters are updated.
ZRO, ZRO rate, and DPP are updated upon generation of a valid GPS velocity.
ZRO and ZRO rate are also updated during periods of zero speed.
When the host uses the “set” procedure with these messages, the “source” field
must be set to “Clear”, “Host Input”, or “Host Override”. The “set” procedure is not
supported for ZRO rate (0x36-08).
For “Clear”, the rest of the fields are ignored.
For “Host Input”, if the device has already calibrated the parameters, the set
procedure is aborted. The acknowledgment message has status set to
“Contradicts current data”.
For “Host Override”, the value and accuracy must be valid quantities.
The “Cal Status” and “newness” fields are always ignored in the set procedure.
Table 67: 0x36-03: ZRO Calibration Message Byte Name Type Units /
LSB Range / Value Meaning
Code U8 0x36
Subcode U8 0x03
0 0-2 Source U3 0
1
2
3
Invalid / Clear
Host Input
Host Override
GPS Fix
0 3 Newness U1 0
1
From BBRAM
New (since start-up)
0 4 Validity U1 1 1 = Valid
1-4 Zero Rate Output
(ZRO)
FLT (mV) (-2500.0, 2500.0)
5-8 ZRO accuracy FLT (mV) > 0 1 σ accuracy