Development of aerial photographing system with throwing device for disaster information gathering
Recently, as a disaster information gathering tool, aerial photographing devices which gather photos and videos from the air get much attention. Especially, the aerial photographing method at low altitude below 15 meters is important to the disaster information gathering. As these devices, there are helium gas balloons, radio-controlled helicopters, and pole/crane vehicles. However, these devices have risks that trigger accidental contact and crackup by air stream at low airspace. In order to improve the safety of these devices, in this paper, we have developed a throw type photographing system which consists of an automatically photographing device packaged in a plastic capsule egg and a launching device. The attitude of the photographing device is controlled by the microcomputer with acceleration, gyro and compass sensors. These sensors also used to estimate the time when the device reaches the top of air. Moreover, we have shown the effectiveness of the proposed system by shooting aerial photographs in practice.
A DCM Based Orientation Estimation Algorithm with an Inertial Measurement Unit and a Magnetic Compass
In this paper, Direction Cosine Matrix (DCM) method for attitude and orientation estimation is discussed. DCM method was chosen due to some advantages over the popular methods such as namely Euler Angle, Quaternion in light of reliability, accuracy and computational efforts. Proposed model for each method is developed for methodology comparison. It is shown that normal Kalman Filter in DCM method is better than extended Kalman Filter in Euler and Quaternion based method because it helps avoid the first order approximation error. Methodology errors are verified using Aerospace Blockset of Matlab Simulink.
Numerical tools applied to power reactor noise analysis
In order to be able to calculate the space- and frequency-dependent neutron noise in real inhomogeneous systems in two-group theory, a code was developed for the calculation of the Green's function (dynamic transfer function) of such systems. This paper reports on the development as well as the test and application of the numerical tools employed. The code that was developed yields the space-dependence of the fluctuations of the neutron flux induced by fluctuating properties of the medium in the two-group diffusion approximation and in a two-dimensional representation of heterogeneous systems, for both critical systems and non-critical systems with an external source. Some applications of these tools to power reactor noise analysis are then described, including the unfolding of the parameters of the noise source from the induced neutron noise, measured at a few discrete locations throughout the core. Other concrete applications concern the study of the space-dependence of the Decay Ratio in Boiling Water Reactors, the noise-based estimation of the Moderator Temperature Coefficient of reactivity in Pressurized Water Reactors, the modeling of the beam- and shell-mode core-barrel vibrations in Pressurized Water Reactors, and the investigation of the validity of the point-kinetic approximation in subcritical systems driven by an external source. In most of these applications, calculations performed using the code are compared with at-power plant measurements. Power reactor noise analysis applications of the above type, i.e. core monitoring without disturbing plant operation, is of particular interest in the framework of the extensive program of power uprates worldwide.