MATLAB analysis

The .tlog files saved by MARSH Manager can be loaded with mavlinktlog function. However, the implementation of mavlinkdialect has the following errors that make reading custom messages more complicated than it would seem from the documentation:

• The parser crashes with "Dot indexing is not supported for variables of this type." when it encounters a message field that does not have a <description> element containing text, which prevents us from loading all.xml
• Seems to ignore the <include>common.xml</include> line in dialect file

To work around this, the messages can be extracted in multiple steps with separate dialect definitions:

dialect_common = mavlinkdialect("common.xml");
logimport_common= mavlinktlog("./data/YYMMDDTHHMMSS_comment.tlog", dialect_common);

sim_state_msgs = readmsg(logimport_common, 'MessageName', 'SIM_STATE');
sim_state_data = sim_msgs.Messages{1};

% This requires a local copy, which would typically be created by update_mavlink.py
dialect_marsh = mavlinkdialect("./mavlink_repo/message_definitions/v1.0/marsh.xml");
logimport_marsh = mavlinktlog("./data/YYMMDDTHHMMSS_comment.tlog", dialect_marsh);

mps_msgs = readmsg(logimport,'MessageName','MOTION_PLATFORM_STATE');
mps_data = mps_msgs.Messages{1};