amrope / ardupilog

A ardupilot log to MATLAB converter

ardupilog

An Ardupilot log to MATLAB converter. Primarily intended to facilitate processing of logs under MATLAB environment.

It is very efficient: The time required to parse large logs is in the order of seconds.

Supported log formats

Currently, only Dataflash logs (.bin files) are supported.

Usage

Add the ardupilog source code to your path. Then,

log = Ardupilog()

will open a file browser, where you can select the log file you want to decode.

Alternatively, the path can be passed directly as a string:

log = Ardupilog('<path-to-log-string>')

The variable struct log will be generated with the included message types as fields. Each field is a variable of type LogMsgGroup.

Each LogMsgGroup under a log contains the following members:

• typeNumID: The message ID.
• name: The declared name string.
• LineNo: The message sequence numbers where messages of this type appear in the log.
• TimeS: The timestamps vector in seconds since boot time, for each message.
• One vector for each of the message fields, of the same length as the timestamps.

Plotting

To plot a specific numerical data field from a specific message, you can enter:

log.plot('<msgName>/<fieldName>');

The full command allows for passnig a Matlab-style line style and an existing Axes Handle to plot in. Additionally, it always returns the Axes Handles it plots in:

ah = log.plot('<msgName>/<fieldName>',<lineStyle>,<axesHandle>)

For example, to plot the Pitch field from the AHR2 message in red, enter:

log.plot('AHR2/Pitch', 'r');

and to plot more than one series in the same figure, you can capture the axis handle of the first plot:

ah = log.plot('AHR2/Roll');
log.plot('AHR2/Pitch', 'r', ah);

Message Filter

You can optionally filter the log file for specific message types:

log_filtered = log.filterMsgs(<msgFilter>)
log_filtered = Ardupilog('<path-to-log', <msgFilter>)

msgFilter can be:

• Either a vector of integers, representing the message IDs you want to convert.
• Or a cell array of strings. Each string is the literal name of the message type.

Slicing

Typically, only a small portion of the flight log is of interest. Ardupilog supports slicing logs to a specific start-end interval with:

sliced_log = log.getSlice([<start_value>, <end_vlaue>], <slice_type>)

• sliced_log is a deep copy of the original log, sliced to the desired limits.
• slice_type can be either TimeS or LineNo.
• <start-value> and <end_value> are either sconds since boot or message sequence indexes.

Example

log_during_cruise = log.getSlice([t_begin_cruise, t_end_cruise], 'TimeS')

Exporting to plain struct

To parse and use the log object created by

log = Ardupilog('<path-to-log>')

requires the ardupilog library to exist in the current MATLAB path.

Creating a more basic struct file, free of the ardupilog dependency, is possible with:

log_struct = log.getStruct();

log_struct does not need the ardupilog source code accompanying it to be shared.

Supported log versions

Logs from the following versions are been tested for Continuous Integration:

• Copter: 3.6.9, 4.0.0, 4.1.0, 4.3.2
• Plane: 3.5.2, 3.7.1, 3.8.2, 3.9.9, 4.0.0, 4.1.0
• Rover: 4.0.0, 4.1.0

LICENSE

This work is distributed under the GNU GPLv3 license.