What is the AV ?

This week, the Avionics team is in the spotlight, the subsystem in charge of the rocket electronics.

The first function of this subsystem is to control the airbrakes allowing the rocket to reach an accurate altitude of 10,000 feet. For this purpose our avionics is based on different sensors and algorithms allowing us to know in real-time the position and speed of the rocket. This information is then given to a control algorithm that chooses the best angle of opening of the airbrakes. This whole cycle only lasts a few milliseconds so as not to be overtaken by the speed of the rocket !

The second function of the avionics is to transmit its data by radio, which allows our team to follow the flight from the ground and to be able to recover the rocket quickly thanks to GPS data.

The success of the mission depends a lot on these two functions, so our avionics must be very reliable during the tests!

How was this implemented?

The first work of the avionics was to define its architecture. Indeed we wanted to implement a modular solution allowing to easily add and repair parts of the avionics. Our idea was therefore to separate the various functions of the project into different components called peripherals: one for the radio connection with the ground, one for the sensors (a barometer and an accelerometer), one to control the airbrakes, a GPS, and finally a last one to easily debug the electronics. Our structure allows us to accommodate up to 10 devices, so we still have room to double some critical functions or for future improvements!

All this equipment is then controlled by several microcontrollers also capable of running higher-level code such as the Kalman filter, an algorithm to merge sensor data in order to know with great precision the position, speed and orientation of the rocket in real-time.

This data can then be transmitted several kilometers away using our flexible antennas that can be integrated into the fuselage of the rocket.

What’s next ?

Despite all this work, the avionics still has many projects in sight!

First, we want to thoroughly test our estimation and control algorithms to characterise precisely their performances. Once this is ensured, it will be possible to add new functionalities which are crucial for the advancement of the project Eiger.

Indeed, our propulsion team is developing a hybrid motor which will need some control from the avionics module; a connexion between the two systems will need to be implemented.

Then, in order to analyse our flight performances, a system of on-ground cameras has to be designed.

Finally, an important aspect of the project is the ergonomy of the avionics which will be redesigned to allow for simpler operations. For that purpose, the mechanical structure will be rethought to be faster to assemble, and new GPS antennas similar to our panel antennas will be developed.

Stay tuned for more updates on the future of the subsystem!

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