We explore adaptive optics (AO) pre-compensation for optical communication between Earth and geostationary (GEO) satellites in a laboratory experiment. Thus, we built a rapid control prototyping breadboard with an adjustable point-ahead angle where downlink and uplink can operate both at 1064 nm and 1550 nm wavelength. With our real-time system, beam wander resulting from artificial turbulence was reduced such that the beam hits the satellite at least 66% of the time as compared to merely 3% without correction. A seven-fold increase of the average Strehl ratio to (28 ± 15)% at 18 μrad point-ahead angle leads to a considerable reduction of the calculated fading probability. These results make AO pre-compensation a viable technique to enhance Earth-to-GEO optical communication.

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This paper presents a new signal representation called Frequency Invariant Transformation of Periodic Signals (FIT-PS) for the context of Non-Intrusive Load Monitoring (NILM). Compared to former approaches, where a conglomeration of different signal forms has been used, the presented approach is based on a single signal form containing all information. The core idea of this work is to use the original current waveform relatively to the reference voltage as a signature for NILM. In general, the relation of sampling and grid frequency is subject to continuous fluctuations. Therefore, FIT-PS converts uncorrelated sample data to a fixed multiple of the grid frequency. The advantages are that the information of the current signal, as well as the phase shift between voltage and current signal are completely contained in the FIT-PS signal representation. For classification, a neural net was applied to the HELD1 [1] dataset. Features created by FIT-PS are clearly superior to the standard features. With 18 different devices, a detection rate of up to 90 % is achieved. In particular, when several consumers are active at the same time, the new signal representation is much more robust and leads to a better detection rate. However, a Long Short-Term Memory (LSTM) net with FIT-PS signal representation provides the best results.

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We present progressive work that is based on our recently developed rapid control prototyping system (RCP), designed for the implementation of high-performance adaptive optical control algorithms using a continuous deformable mirror (DM). The RCP system, presented in 2014, is resorting to a Xilinx Kintex-7 Field Programmable Gate Array (FPGA), placed on a self-developed PCIe card, and installed on a high-performance computer that runs a hard real-time Linux operating system. For this purpose, algorithms for the efficient evaluation of data from a Shack-Hartmann wavefront sensor (SHWFS) on an FPGA have been developed. The corresponding analog input and output cards are designed for exploiting the maximum possible performance while not being constrained to a specific DM and control algorithm due to the RCP approach. In this second part of our contribution, we focus on recent results that we achieved with this novel experimental setup. By presenting results which are far superior to the former ones, we further justify the deployment of the RCP system and its required time and resources. We conducted various experiments for revealing the effective performance, i.e. the maximum manageable complexity in the controller design that may be achieved in realtime without performance losses. A detailed analysis of the hidden latencies is carried out, showing that these latencies have been drastically reduced. In addition, a series of concepts relating the evaluation of the wavefront as well as designing and synthesizing a wavefront are thoroughly investigated with the goal to overcome some of the prevalent limitations. Furthermore, principal results regarding the closed-loop performance of the low-speed dynamics of the integrated heater in a DM concept are illustrated in detail; to be combined with the piezo-electric high-speed actuators in the next step