Abstract: An aircraft includes a fuselage, a main wing, and a flight controller. The main wing is attached to the fuselage and configured to generate lift that acts on the aircraft. The flight controller includes an electric field direction estimator, an attitude calculator, and an attitude controller. The electric field direction estimator is configured to estimate a direction of an electric field around the aircraft. The attitude calculator is configured to calculate a target airframe attitude that reduces a possibility of occurrence of lightning strike on the aircraft, on the basis of the direction of the electric field estimated by the electric field direction estimator. The attitude controller is configured to control an attitude of an airframe of the aircraft to cause the attitude of the airframe to be the target airframe attitude calculated by the attitude calculator.

Abstract: A fastening structure includes a first structural member, a second structural member, and a fastening member. The first structural member includes a composite material, and has a first electrically-conductive surface having electric conductivity. The second structural member has a second electrically-conductive surface. The second electrically-conductive surface is in contact with the first electrically-conductive surface and has electric conductivity. The fastening member penetrates the first electrically-conductive surface and the second electrically-conductive surface, and fastens the first structural member and the second structural member.

Abstract: An aircraft includes a fuselage, a main wing, an electric field sensor, and a flight controller. The electric field sensor is configured to detect surface electric field intensities at four or more of mutually different positions on the aircraft. The flight controller includes a storage, a data extracting unit, an electric field intensity calculator, and an attitude control unit. The storage holds an electric field distribution table. The data extracting unit is configured to extract one of pieces of distribution data from the electric field distribution table. The electric field intensity calculator is configured to calculate surface electric field intensities at respective positions on the basis of the extracted piece of the distribution data. The attitude control unit is configured to perform prevention operation of the aircraft on the basis of the calculated surface electric field intensities at the respective positions.

Abstract: An information transmission system includes an encoder, a display, an imaging apparatus, and a decoder. The encoder is mounted on a first aircraft and is configured to encode information to create a secret code. The display is mounted on the first aircraft and is configured to display the secret code created by the encoder at a predetermined position on a surface of a body of the first aircraft. The imaging apparatus is mounted on a second aircraft and is configured to capture an image of the first aircraft. The decoder is mounted on the second aircraft and is configured to detect an image region including the secret code from the image captured by the imaging apparatus, decode the secret code by performing image processing on the detected image region, and read the information.

Abstract: According to one implementation, an aviation system 100 includes electric field sensors 112 and a ground system 114 including a computer configured to communicate with each of the electric field sensors 112. The computer is configured to: acquire electric field intensities from the electric field sensors 112 respectively, and generate a first electric field distribution on a ground surface 16 based on the electric field intensities; derive a matrix; derive a pseudo inverse matrix of the matrix; derive an electric charge distribution on the horizontal plane by multiplying the pseudo inverse matrix by the first electric field distribution on the ground surface 16; and derive a second electric field distribution on a flight path based on the electric charge distribution. The first electric field distribution on the ground surface 16 is derived by multiplying the matrix by electric charges temporarily set on a horizontal plane at a predetermined altitude.

Abstract: An information transmission system includes an encoder, a display, an imaging apparatus, and a decoder. The encoder is mounted on a first aircraft and is configured to encode information to create a secret code. The display is mounted on the first aircraft and is configured to display the secret code created by the encoder at a predetermined position on a surface of a body of the first aircraft. The imaging apparatus is mounted on a second aircraft and is configured to capture an image of the first aircraft. The decoder is mounted on the second aircraft and is configured to detect an image region including the secret code from the image captured by the imaging apparatus, decode the secret code by performing image processing on the detected image region, and read the information.

Abstract: An aircraft includes a fuselage, a main wing, an electric field sensor, and a flight controller. The electric field sensor is configured to detect surface electric field intensities at four or more of mutually different positions on the aircraft. The flight controller includes a storage, a data extracting unit, an electric field intensity calculator, and an attitude control unit. The storage holds an electric field distribution table. The data extracting unit is configured to extract one of pieces of distribution data from the electric field distribution table. The electric field intensity calculator is configured to calculate surface electric field intensities at respective positions on the basis of the extracted piece of the distribution data. The attitude control unit is configured to perform prevention operation of the aircraft on the basis of the calculated surface electric field intensities at the respective positions.

Abstract: An aircraft includes a fuselage, a main wing, and a flight controller. The main wing is attached to the fuselage and configured to generate lift that acts on the aircraft. The flight controller includes an electric field direction estimator, an attitude calculator, and an attitude controller. The electric field direction estimator is configured to estimate a direction of an electric field around the aircraft. The attitude calculator is configured to calculate a target airframe attitude that reduces a possibility of occurrence of lightning strike on the aircraft, on the basis of the direction of the electric field estimated by the electric field direction estimator. The attitude controller is configured to control an attitude of an airframe of the aircraft to cause the attitude of the airframe to be the target airframe attitude calculated by the attitude calculator.

Abstract: A fastening structure includes a first structural member, a second structural member, and a fastening member. The first structural member includes a composite material, and has a first electrically-conductive surface having electric conductivity. The second structural member has a second electrically-conductive surface. The second electrically-conductive surface is in contact with the first electrically-conductive surface and has electric conductivity. The fastening member penetrates the first electrically-conductive surface and the second electrically-conductive surface, and fastens the first structural member and the second structural member.

Abstract: An electromagnetic field analysis method for an anisotropic conductive material involves using an analysis grid having a first side and a second side that are orthogonal to each other to analyze an electromagnetic property of an anisotropic conductive material in which conductivity in a first direction is different from conductivity in a second direction. One or both of the first direction and the second direction are parallel to a direction different from either one of the first side and the second side of the analysis grid. One electromagnetic field component located on the first side and extending along the second side is calculated based on electromagnetic field components that are located on a plurality of the second sides surrounding the one electromagnetic field component and that extend along the second sides.

Abstract: In a non-contact discharge test performed in a poor electromagnetic noise environment, the energy of discharge is evaluated by detecting weak light emission and processing the intensity waveform of light emission of the discharge. A database is created by measuring the intensity waveform of light emission of discharge generated as a result of application of a voltage or current to a measurement object through use of a light emission measuring device, simultaneously measuring the current waveform of the discharge through use of a current measuring device, and storing in the database the relation between analysis data sets obtained through analysis of the waveforms on the basis of information of the voltage or current applied to the measurement object. The intensity waveform of the light emission of the discharge or spark generated from the measurement object is measured while an electromagnetic wave generated as a result of the discharge of the measurement object is used as a reference.

Abstract: An electromagnetic field analysis method for an anisotropic conductive material obtained by laminating a first layer, in which a conductivity in a first direction is different from a conductivity in another direction, and a second layer, in which a conductivity in a second direction is different from that in another direction includes: grid-partitioning the first and second layers respectively with a first computational grid having a side extending in the first direction and a second computational grid having a side extending in the second direction; calculating an electromagnetic component of one of electric and magnetic fields in the second grid by interpolation from distribution of an electromagnetic component of the one of electric field and magnetic fields in the first grid; and calculating an electromagnetic component of the other field in the first grid by interpolation from distribution of an electromagnetic component of the other field in the second grid.

Abstract: An electromagnetic field analysis method for an anisotropic conductive material involves using an analysis grid having a first side and a second side that are orthogonal to each other to analyze an electromagnetic property of an anisotropic conductive material in which conductivity in a first direction is different from conductivity in a second direction. One or both of the first direction and the second direction are parallel to a direction different from either one of the first side and the second side of the analysis grid. One electromagnetic field component located on the first side and extending along the second side is calculated based on electromagnetic field components that are located on a plurality of the second sides surrounding the one electromagnetic field component and that extend along the second sides.

Abstract: A current measurement device measures current flowing in a composite material M containing conductive fibers. The current measurement device includes a temperature measuring unit that measures the temperature of a surface of the composite material, upon flow of current in the composite material; a storage unit that stores conversion data that is acquired as a result of a conversion data acquisition test performed beforehand and that results from converting the temperature of the surface of the composite material to the value of the current flowing in the composite material; and a current calculator that, on the basis of the conversion data stored in the storage unit, converts the temperature of the surface of the composite material M as measured by the temperature measuring unit to a value of the current flowing in the composite material.

Abstract: An electromagnetic field analysis method for an anisotropic conductive material obtained by laminating a first layer, in which a conductivity in a first direction is different from a conductivity in another direction, and a second layer, in which a conductivity in a second direction is different from that in another direction includes: grid-partitioning the first and second layers respectively with a first computational grid having a side extending in the first direction and a second computational grid having a side extending in the second direction; calculating an electromagnetic component of one of electric and magnetic fields in the second grid by interpolation from distribution of an electromagnetic component of the one of electric field and magnetic fields in the first grid; and calculating an electromagnetic component of the other field in the first grid by interpolation from distribution of an electromagnetic component of the other field in the second grid.

Abstract: In a non-contact discharge test performed in a poor electromagnetic noise environment, the energy of discharge is evaluated by detecting weak light emission and processing the intensity waveform of light emission of the discharge. A database is created by measuring the intensity waveform of light emission of discharge generated as a result of application of a voltage or current to a measurement object through use of a light emission measuring device, simultaneously measuring the current waveform of the discharge through use of a current measuring device, and storing in the database the relation between analysis data sets obtained through analysis of the waveforms on the basis of information of the voltage or current applied to the measurement object. The intensity waveform of the light emission of the discharge or spark generated from the measurement object is measured while an electromagnetic wave generated as a result of the discharge of the measurement object is used as a reference.

Abstract: A current measurement device measures current flowing in a composite material M containing conductive fibers. The current measurement device includes a temperature measuring unit that measures the temperature of a surface of the composite material, upon flow of current in the composite material; a storage unit that stores conversion data that is acquired as a result of a conversion data acquisition test performed beforehand and that results from converting the temperature of the surface of the composite material to the value of the current flowing in the composite material; and a current calculator that, on the basis of the conversion data stored in the storage unit, converts the temperature of the surface of the composite material M as measured by the temperature measuring unit to a value of the current flowing in the composite material.

Abstract: The damage length measurement system has an object being measured that comprises a plurality of members is vibrated by an oscillator, and the vibration that propagates through the object being measured is detected by three sensors. A measurement apparatus analyzes that vibration wave, and measures the arrival time of the maximum peak. Using the fact that the time for a wave to propagate between two vibration detection sensors separated by a set interval is fixed, the measurement apparatus determines whether the difference in arrival time between two sensors is within a set reference range that includes the vibration propagation time between two vibration sensors. When the measurement apparatus determines that the difference is not within the set reference range, uses the fact that that wave is delayed compared to the wave that was to be detected.

Abstract: The damage length measurement system has an object being measured that comprises a plurality of members is vibrated by an oscillator, and the vibration that propagates through the object being measured is detected by three sensors. A measurement apparatus analyzes that vibration wave, and measures the arrival time of the maximum peak. Using the fact that the time for a wave to propagate between two vibration detection sensors separated by a set interval is fixed, the measurement apparatus determines whether the difference in arrival time between two sensors is within a set reference range that includes the vibration propagation time between two vibration sensors. When the measurement apparatus determines that the difference is not within the set reference range, uses the fact that that wave is delayed compared to the wave that was to be detected.