Logging

On-board logging is performed using the goby_logger application, which logs every message published on the Goby3 interprocess layer to a binary .goby log file.

This log file can be converted in post-processing to several formats for use by data processing tools.

Log generation

When goby_logger is run (e.g. in simulation using the auv.launch script in jaiabot-configuration, see Configuration), it writes a file (e.g. auv0_29971128T082058.goby) to the log directory (/tmp/jaia-logs/bot/0 in the simulator for bot0, where /tmp/jaia-logs can be changed in the preseed.goby in jaiabot-configuration).

Log processing

After the mission is complete, the .goby log can be copied off the vehicle (e.g. using rsync) and processed.

Debug text log

The Goby log can be converted into a text file version of all the publications (for visual inspection and debugging) using

goby_log_tool --input_file bot0_29971128T082058.goby --format DEBUG_TEXT

which writes bot0_29971128T082058.txt by default (override by setting --output_file). This file can be inspected by any standard text viewer or editor.

HDF5 file

An HDF5 file suitable for use in MATLAB, Octave, etc. can be generated using:

goby_log_tool --input_file bot0_29971128T082058.goby --format HDF5

which writes bot0_29971128T082058.h5 by default (also can be overridden by setting --output_file).

Octave example

The HDF5 file can be read into Octave using:

octave --eval 'load /tmp/jaia-logs/bot/0/bot0_29971128T082058.h5' --persist
octave:1> who
Variables in the current scope:
 
goby__middleware__frontseat__desired_course  goby__terminate__response
goby__middleware__frontseat__helm_state      goby__terminate__result
goby__middleware__frontseat__node_status     goby__zeromq___internal_manager_request
goby__middleware__groups__gpsd__att          goby__zeromq___internal_manager_response
goby__middleware__groups__gpsd__tpv          udp_in
goby__terminate__request

All the HDF5 data are loaded using the group name followed by the Protobuf type name, followed by the fields (with reserved characters :, ., etc. turned into _), e.g.:

goby__middleware__frontseat__node_status.goby_middleware_frontseat_protobuf_NodeStatus.speed.over_ground

is the HDF5 format for:

• Goby group: goby::middleware::frontseat::node_status
• (Protobuf) type: goby.middleware.frontseat.protobuf.NodeStatus
• (Protobuf) field: speed [Message]
  • over_ground [double]

This simple .m file will plot the vehicle's position in latitude/longitude for the entire mission:

load /tmp/jaia-logs/bot/0/bot0_29971128T082058.h5
node_status = goby__middleware__frontseat__node_status.goby_middleware_frontseat_protobuf_NodeStatus;
plot(node_status.global_fix.lat, node_status.global_fix.lon);

(which produces for a simple octagon mission):