A flight-path reconstruction algorithm for tethered aircraft, which is based on an extended Kalman filter, is presented. The algorithm is fed by the measurements of a set of onboard and ground-based instruments and provides the optimal estimation of the system state-space trajectory, which includes typical aircraft variables such as position and velocity, as well as an estimation of the aerodynamic force and torque. Therefore, it can be applied to closed-loop control in airborne wind energy systems and it is a first step toward aerodynamic parameter identification of tethered aircraft using flight-test data. The performance of the algorithm is investigated by feeding it with real flight data obtained from a low-cost and highly portable experimental setup with a four-line kite. Several flight tests, which include pullup and lateral-directional steering maneuvers with two kites of different areas, are conducted. The coherence of the estimations provided by the filter, such as the kite state-space trajectory and aerodynamic forces and torques, is analyzed. For some standard variables, such as kite Euler angles and position, the results are also compared with a second independent onboard estimator.

-In this contribution a C-Band 2 nd harmonic tuned hybrid power amplifier utilizing a PHEMT GaN device is presented, together with technological aspects, non linear device model and adopted design criteria. The amplifier has been realised in hybrid form, exhibiting a bandwidth larger than 20% around 5.5GHz, with a minimum output power of 33 dBm, and a drain efficiency of 60% at the centre frequency.

International audienceThe present paper presents the transistor modeling work achieved in the GaN European project KorriGaN (Key Organisation for Research in Integrated Circuits in GaN technology). The KorriGaN project (200509) has released 29 GaN circuits such as high-power amplifiers (HPAs), low-noise amplifiers (LNAs), and switches. Modeling is one of the main key to reach successful designs. Therefore, nonlinear models of European GaN HEMT models have been developed. This work deals with characterization tools such as pulsed IV, pulsed S parameters, load-pull measurements, and measurement-based methods to perform GaN HEMT compact models parameters extraction. The present paper will describe the transistor modeling activities in KorriGaN for HPA designs (nonlinear models including trapping and/or self-heating effects) and LNA designs (nonlinear models and noise parameters)

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