SeaTrac Serial Command Interface Reference
Page 46
6.4.2.
ACOFIX_T (Acoustic Position and Range Fix Summary)
The Acoustic Fix structure is produced by the acoustic transceiver module and contains a
summary of any information relating to a received signal – this includes current beacon depth,
beacon attitude, water VOS, signal strength and any information that can be computed relating
to the remote beacons range and position.
The data record varies depending on the contents of the FLAGS field, with required fields being
appended to the end of the record as required.
For details of attitude definitions refer to section 9.1 on page 136.
Parameter Type Description
DEST_ID
The ID code of the beacon that this data is sent to.
Normally this is the local beacon ID code, but a
value of BEACON_ALL indicates data has been
transmitted to all beacons.
Valid values are form 0 to 15.
SRC_ID
The ID code of the beacon that sent the data.
Valid values are form 1 to 15.
FLAGS
UINT8
A bit-field of flags used to indicate what the rest of
the record contains.
Bit values are…
Bit[7:5] = RESERVED
These bits are reserved for future use
Bit[4] = POSITION_FLT_ERROR If this bit is true, it indicates the position filter has
identified that the position specified in the fix may
be invalid based on the beacons previous position,
the define beacons motion limits and the time since
last communication. However, the position fields
still contain the USBL computed position and it is up
to the user if they wish to reject this fix, or use it in
some direct or weighted fashion.
Bit[3] = POSITION_ENHANCED
If this bit is set, it indicates the Position fix has
been computed from an Enhanced USBL return –
this means the Depth will be the value from the
remote beacons depth sensor rather than computed
form the incoming signal angle.
Bit[2] = POSITION_VALID
If this bit is set, it indicates the record contains the
Position fields discussed below.
Bit[1] = USBL_VALID
If this bit is set, it indicates the record contains the
USBL fields discussed below.
