Recently, the developments on the low Reynolds number aircraft such as micro air vehicle and unmanned aircraft for Mars exploration have been increased. In this study, Oswald efficiency factor of the wing, which is available to estimate aircraft performance, was predicted through wind tunnel tests at a Reynolds number of 1 × 10⁴. Rectangular flat-plate wings with aspect ratios varying from 0.5 to 5 were tested in this study. Although efficiency factor of the wing with aspect ratio of 0.5 was close to 1, it decreased significantly as the aspect ratio increased. As the aspect ratio increased more than 3, the efficiency factor decreased to less than 0.4. The efficiency factor of the rectangular wing with the thin circular arc airfoil with 3%c camber, which shows large lift-to-drag ratio at the present Reynolds number, was larger than that of thin flat plate wing. The two efficiency factors were set to estimate the drag coefficient of the wing having non-linear lift curve. However, the efficiency factor of the wing at this low Reynolds number was much lower than that of commonly used airplane wings.

GNSS Spoofing is of great concern for applications in fields where reliability is important, such as automatic operation of ships, aircraft, automobiles, and flying vehicles (AAM: Advanced Air Mobility) since it hijacks the location information by imitating GNSS signals and transmitting them to the receiver. An antenna array has been proposed as a countermeasure against spoofing. In this paper, through spoofing experiments in an open-sky environment, we attempted to estimate the DOA (Direction Of Arrival) of impinging signals for spoofing detection by the GNSS antenna array and to suppress its adverse effects on positioning. The DOA of spoofing was estimated by the MUSIC algorithm using Nullspace Projection which eliminates a real satellite, and then Nullspace Projection onto the spoofing signal subspace and beamforming to the desired wave were applied together to suppress spoofing. Finally, reasonable direction estimation results were obtained, and the positioning errors were reduced to a few tens of meters among the disturbances caused by spoofing.

We established a Free Drift (FD) method to remotely measure the force generated on an isolated object simulated using an Electro-static Levitation Furnace (ELF). The FD method can be applied in high power laser ablation experiments, where the change in the electric charge of sample is big. The analyses to deduce the thrust are described in detail. Using this method in the ELF on the International Space Station (ISS), we had successfully measured the thrust generated by laser beam irradiation to an Al droplet for the first time. The momentum coupling coefficient (C_m) when irradiated by a laser beam with a laser power density of 10³-10⁴ W/cm² was around 10⁰ N/GW.