The paper includes a summary of long-time research conducted by a research team in the Institute of Electrical Engineering and Computer Science at Silesian University of Technology. The research work has principally been related to selected problems in the field of analysis and synthesis of systems aimed at symmetrisation and improvement of some power quality parameters. This paper constitutes the second part of the report on the research. It has been devoted to three-phase system symmetrisation as well as effective elimination of higher harmonics and substantial improvement of power quality by means of hybrid active power filters.

The advance of MEMS-based inertial sensors successfully expands their applications to small unmanned

aerial vehicles (UAV), thus resulting in the challenge of reliable and accurate in-flight alignment for airborne

MEMS-based inertial navigation system (INS). In order to strengthen the rapid response capability

for UAVs, this paper proposes a robust in-flight alignment scheme for airborne MEMS-INS aided by global

navigation satellite system (GNSS). Aggravated by noisy MEMS sensors and complicated flight dynamics,

a rotation-vector-based attitude determination method is devised to tackle the in-flight coarse alignment

problem, and the technique of innovation-based robust Kalman filtering is used to handle the adverse impacts

of measurement outliers in GNSS solutions. The results of flight test have indicated that the proposed

alignment approach can accomplish accurate and reliable in-flight alignment in cases of measurement outliers,

which has a significant performance improvement compared with its traditional counterparts.