P Datalog

Along with datalogging on the ground with wireless telemetry, APM also automatically datalogs in the air using its built-in dataflash memory. You can access this data by plugging in your USB cable and using the Terminal tab in the Mission Planner.

http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/MPlogdownload.PNG

Downloading log files

First, ensure that your slider switch is in CLI mode (towards servo rails) and that you've selected the right Com port for your board in the Mission Planner configuration menu.

Select "Log Download" from the Mission Planner Terminal tab. A list of logs from the onboard memory will be shown. You can either select individual files to download or download all of them. They will be saved in your APMMissionPlanner/logs folder, along with a KML, that can be opened in Google Earth.

Note: It can take a long time (several minutes) to download a big log file. Do not interrupt the process until the software reports that it's finished. You can see visual confirmation that data transfer is happening by looking at the Rx LED on your IMU shield. It will be on during data transfer, and go off when it's done.

Analyzing log files

http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/MPlogbrowse.PNG

Once you've downloaded log files, you can analyze them. Click on a log file to analyze, and the Log Browser should open.

This can be a little hard to understand, but here are the basics:

• Each row represents a data log, which is usually done several times a second
• The first 256 lines are just mission commands ("CMD")--scroll down past them. After that the default log data will alternate between Attitude data ("ATT") and GPS data ("GPS"). If the GPS data is 0s that means that APM didn't have GPS lock at that time.
• You will probably be most interested in the Attitude data. This comes in three forms: Roll, Pitch and Yaw. Click on any cell in the table to graph that data type; you can pick up to five
• You can add other many data fields to your log file, from performance monitoring to navigation calculations. A full list and instructions are here.

You can click on any cell to add that kind of data to the data already graphed.

You can use your mouse's scroll wheel to zoom in or out on the data, or drag a box around the area of data you're interested in to have it fill the window.