Measuring Altitude and Atmospheric Pressure in an Airplane

I had an unique opportunity to measure cosmic radiation during a flight on an airplane (Pilatus PC-6 Turbo-Porter) typically used for skydiving. The airplane can reach an altitude of up to 4 km and then return to the ground.

To accurately process the data on cosmic radiation, we needed to precisely measure pressure(-altitude) and altitude. Since I learned about this opportunity shortly before the scheduled flight, I had to act quickly and assemble the necessary sensor setup.

I took a set of MLAB modules that I had available and assembled a device containing a precise GNSS (GPS) receiver, an I2C barometer, and a USB-I2C converter. I mounted the entire device on a carrier aluminum plate and started programming. I used existing examples in PyMLAB and created a script suitable for this purpose.

I connected the MLAB GPS02B to the computer via USB and started gpsd on this USB port, which solved the GPS reading and position distribution within the system. This was very simple.

The next step was to connect the barometer. I used the ALTIMET01A module, which contains the MPL115A sensor. With a simple modification of the existing script for reading this sensor, I created a new script that also read GPS position from gpsd and logged the data into a CSV format.

And that was it! I easily created a tracker for altitude and pressure. Additionally, during the flight, I had nice GUI displays that showed the values from the GPS.

This is how the measured data looked like:

More about the cosmic radiation measurement experiment can be found in this repository.