BOOMERANG
Engineering
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The information on attitude, position, and velocity from the navigation is used to compute a trajectory to the designated landing location.
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The Navigation code makes use of several sensors such as an accelerometer, magnetometer, gyroscope, and GNSS to compute an optimal estimation of the state of the FFU with the use of a multiplicative extended Kalman filter (MEKF). The state consists of position, velocity, accelerometer bias, attitude error components, and gyroscope bias.
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The error between the current and target position given by the guidance is used in a controller to compute the control law that allows steering the paraglider. The two break lines of the paraglider are attached to the motor that, when spinning, pulls one or the other break line, thus increasing the drag on one side of the paraglider and allowing the Free Falling Unit to steer its trajectory.
The Guidance Navigation and Control (GNC) system is basically the brain of our experiment. By reading the sensors it is capable of obtaining the FFUs attitude or orientation as well as its position and velocity during flight. This information is used to compute the trajectory to the landing location. The difference in position and the calculated trajectory - the so-called error - is used in a controller to steer the paraglider. The code is initially developed and tested in MATLAB and then coded to C to program the microcontroller.