Flight Log Analysis
Last updated
Last updated
This topic provide an overview of the tools and methods that can be used to analyze PX4 flight logs (more detailed topics are linked below in some cases).
:::note explains how to download a log and report/discuss issues about a flight with the development team. :::
Before analyzing a flight log it is important to establish its context:
If the analysis is done after a malfunction, did the log capture the crash or did it stop mid-air?
Did all controllers track their references? The easiest way to establish this is to compare attitude roll and pitch rates to their set points.
Does the sensor data look valid? Was there very strong vibration (a reasonable threshold for strong vibration is anything with a peak-to-peak of more than 2-3 m/s/s).
If the root cause is not specific to the vehicle make sure to report it with a link to the log file (and video if one exists) on the .
If a log file ends mid-air, two main causes are possible: a power failure or a hard fault of the operating system.
On autopilots based on the , hard faults are logged to the SD card. These are located on the top level of the SD card and named fault_date.log, e.g. fault_2017_04_03_00_26_05.log. You should check for the presence of this file if a flight log ends abruptly.
is the successor of Log Muncher. It is used in combination with the new logging format.
Key features:
Web based, great for end-users.
Interactive plots.
It supports ULog files (.ulg) since version 2.1.4.
Key features:
Intuitive drag & drop interface.
Arrange your data in multiple plots, tabs or windows.
All uORB topics are shown and can be graphed.
Once you arranged your data, save it into a "Layout" file and reload it multiple times.
Process your data inside PlotJuggler itself, using custom "data transformations".
Key features:
Python library for parsing ULog files. Base library used by a number of other ULog analysis and visualisation tools.
Scripts to extract/display ULog information:
ulog_info: display information from an ULog file.
ulog_messages: display logged messages from an ULog file.
ulog_params: extract parameters from an ULog file.
Scripts to convert ULog files to other formats:
ulog2csv: convert ULog to (several) CSV files.
ulog2kml: convert ULog to (several) KML files.
All scripts are installed as system-wide applications (i.e. they be called on the command line - provided Python is installed), and support the -h flag for getting usage instructions. For example:
Below we see the kind of information exported from a sample file using ulog_info.
Key features:
Java based, cross-platform.
Intuitive GUI, no programming knowledge required.
Supports both new and old PX4 log formats (.ulg, .px4log, .bin)
Allows saving plots as images.
Key features:
Python based, cross platform, works with anaconda 2 and anaconda3
iPython/ jupyter notebooks can be used to share analysis easily
Advanced plotting capabilities to allow detailed analysis
Key features:
Realtime data acquisition (50ms sampling, 100ms rolling display) based on MAVLink messages or ULOG data over MAVLink
Timechart annotated by messages (MAVLink and ULog) and parameter changes (MAVLink only)
XY Analysis for selected key-figures
3D View (vehicle and observer perspective)
MAVLink inspector (reporting raw MAVLink messages)
Offline-mode: Import of key-figures from PX4Log/ULog (file or last log from device via WiFi)
Java based. Known to work on macOS and Ubuntu.
And many more ...
You can use the online version of the tool for small log files (< 32Mb), or run it locally in order to analyze longer flights.
Users can upload logs through the web interface, and then share report with others (bulk upload is supported using the script)
See for an introduction.
is a desktop application that allows users to easily visualize and analyze data expressed in the form of time series. This is one of the best ULog analysis tools as it exposes all information in the log (, by comparison, only shows a small subset of the data).
Source code and downloads are available on .
See for an introduction.
is a python package to parse ULog files, along with a set of command-line scripts to extract/display ULog information and convert them to other file formats.
is a desktop based tool for log analysis. It can be downloaded from (Linux, MacOS, Windows).
is a log analysis toolbox for the PX4 autopilot written in Python. The recommended installation procedure is to use . See for details.
Easy to share, users can view notebooks on Github (e.g. )
is an in-flight log analyzer for PX4. It can also be used in offline mode with downloaded uLog files.
is a interactive PX4 flight log analysis tool that allows you to encode flight data onto the flight path, filter and brush the data by time - and much more!
