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Automatic Dependent Surveillance-Broadcast (ADS-B) is one of the key available technologies for aircraft surveillance. ADS-B provides high accurate GNSS positions with high update rate for air traffic control and airline operations. This feature will improve the safety and efficiency of air traffic operations. However, ADS-B user cannot benefit from the accuracy capability because the ADS-B message does not include information of GNSS measured time and because of the latency between the GNSS measured time and ADS-B message arrival time. In this paper, we propose a technique to estimate the variable element of ADS-B latency. Then, the proposed technique is applied to real data obtained by ENRI experimental system. The results of the estimations are presented in support of performance assessment.

In order to provide service for millimeter wave terminals in environments such as a stadium, the centralized Radio Access Network system is under development. In this paper, we propose millimeter wave communication system connected by Radio over Fiber (RoF). We also introduce the dynamic cell control by the wavelength of light to create the cell size freely. In addition, we report the result of evaluation of distributing wireless signals connected by the optical network from two 60 GHz base stations to four remote antenna units.

We have carried out research and development of next generation (5G) wireless communication systems in dense user environments utilizing advanced photonic technologies. Especially, we have focused on a heterogeneous wireless communication system, which includes 4G, 3G, WiFi and millimeter-wave wireless links, with broadband, low latency, low-power consumption and low-cost. In this report, photonic-based millimeter-wave wireless links of ultra-small cells (atto-cells) in a big football stadium are discussed. Advantages of an asymmetric millimeter-wave link combined with terminal localization techniques are also pointed out. Some basic experimental results on the millimeter-wave wireless links in an actual big football stadium are also reported.

This paper presents the estimation of a 1090 MHz signal environment on an airport surface. Secondary surveillance radar and its applications share the 1030 MHz and 1090 MHz frequency bands. Many aircraft emit signals lying in the same frequency band; the consequent increase in the signal amount causes saturation and results in performance degradation. To meet aviation requirements, it is important to manage the signal amount. In this paper, we focus on the 1090 MHz signals and propose an estimation method for the signal amount on an airport surface by using a multilateration system.

This paper mentioned the function of mobile terminal positioning for beam forming to millimeter-wave terminals in high-density user environment. The positioning method discussed in this paper is hyperbolic positioning using time differences of arrival of the millimeter wave signals from mobile terminals. Some preliminary time measurement experiments of millimeter wave have been executed with RoF connection remote receivers developed for this positioning purpose. In addition, simulation study also has been made to estimate the positioning accuracy. As a result, high accuracy positioning of millimeter wave mobile terminal seemed to be achieved.

Under the dense user conditions such as stadia, the millimeter wave propagation might be influenced by the reflection from surrounding spectators. In this paper, we analyze millimeter wave propagation, which becomes a problem in realizing millimeter wave communication at the stadium. In order to extend the distance between the transmitter and the receiver, a millimeter wave propagation measurement system using radio over fiber was developed. By using the system, Millimeter Wave (MMW) propagation irradiated from the ceiling of the stadium to the spectator seats was analyzed. If the cell is set small with the directional antenna, it is found that the influence of the reflection of the surrounding spectators is small, and a good prospect is obtained.

International audience; Automatic-dependent surveillance-broadcast (ADS-B) receivers are vulnerable to jamming and spoofing attacks. Air traffic management is expected to heavily rely on ADS-B in the future so it is important to provide protection against these attacks. One promising solution is array signal processing. Jamming signals can be suppressed by beamforming and ADS-B positions can be verified by comparing them to the measured angles of arrival (AoAs). Many studies have been done on this topic but they generally consider either jamming or spoofing. However, in a real environment, anti-jamming and anti-spoofing functions must be provided together. It is important to understand the performance when these two functions are implemented simultaneously in order to guide future research and development strategies and implementation plans. Thus, we conducted an experimental evaluation of anti-jamming and anti-spoofing functions. For jamming protection, a power-inversion beamformer was used to suppress the jamming signal. For spoofing protection, a Capon’s beamformer was used to measure the AoA. The array used was a uniform linear array of four elements. The experiments were conducted in an anechoic chamber using a four-channel oscilloscope and the signal processing was conducted offline. The results of the anti-jamming experiment showed that the jammed signals were successfully recovered and the signal-to-jamming-plus-noise (SJN) ratio was increased to above the decodable level. The effects of various parameters on the overall performance and the lower bound performance were also investigated. Moreover, the anti-spoofing experiment showed that the AoA of the ADS-B signal could be measured successfully. The AoA accuracy was evaluated in terms of the standard deviation, which was further converted into the probability of spoofing detection. These findings will be important in the implementation of effective infrastructure to ensure safe air travel.

Photonic-based millimeter-wave communication systems combined with conventional wireless systems have been proposed for the application in dense user environments like a large football stadium. By utilizing a narrow beam antenna for millimeter-wave asymmetric links, effective communication channels can be obtained.

SUMMARY Multilateration is an aircraft surveillance system for airport surface movement utilizing hyperbolic positioning. The system performance is sometimes degraded by multipath signals in airport apron areas. ENRI has proposed an enhanced multilateration system named OCTPASS (Optically Connected Passive Surveillance System), which has interference immunity in a multipath environment. This paper describes evaluation results for OCTPASS prototype equipment.

The Contactless Power Station (CLPS) is a cordless power supply system that makes use of electromagnetic induction generated by means of coils. We propose a desktop design for CLPS, using spiral coils, because it is convenient to be able to charge the batteries of a digital still camera, a cellular phone, and a PC on single desk. The primary coil are arranged so that the coupling factor becomes 0, since it is inconvenient for the primary coils to be excited by each other. However, when the primary coils are synchronized and driven, the magnetic flux interferes with the electric power transmission. Attention was paid to changing each phase on the primary coils. As a result, when the phase was moved, stabilization of the output voltage was confirmed. Therefore, if the primary coils are suitably arranged, the power transmission pad can stabilize electric power transmission everywhere.

This article presents some progress in the development for preclinical trials of an artificial anal sphincter using shape memory alloys. The novel device has been proposed and developed by the author's group at Tohoku University. It has two dominant features different from other systems, which are either clinically available or still under development. One is that a solid driving element, a combination of shape memory alloy (SMA) ribbons and silicone elastomer sheets with a layered structure, is adopted for the opening and closing functions of the artificial sphincter. The other is a sandwich mechanism for the closing of bowel to reduce the risk of buckling induced ischemia which has been reported in hydraulically driven artificial sphincters with a radial squeezing mechanism. The device has fewer parts inside the body and therefore be implanted more easily. A new design eliminating the risk of heat burns enables long-term implantation and brings the device closer to practical use. Functionality and safety of the device have been proved in three-month animal experiments.

Implant medical devices are physically isolated from power sources required to supply driving energy to them. A well-known contactless power transmission technology is the transcutaneous energy transmission system (TETS), which applies electromagnetic induction between two disk-like spiral coils (a primary coil outside the body, and a secondary coil inside the body). Implant devices that require a temperature rise for their actuation must be prevented from overheating, and transcutaneous control and monitoring of the devices? temperature is necessary. A small inductor with a thermosensitive ferrite core was developed as a thermo-sensing device. This inductor controls the temperature automatically inside the body in combination with TETS. A coupling factor change between the two coils of a TETS transformer also affects the stability of power transmission characteristics. A suitable excitation frequency was designed to ensure stable driving. The control system referred to above has been applied in an artificial anal sphincter system that is now being developed, and appropriate driving has been observed.

The implant medical device discussed here is an artificial sphincter that utilizes shape memory alloy (SMA). This device is implanted into the body of a patient to provide independent evacuation for a patient using an artificial anus. The artificial sphincter operates based on the phase transformation of the SMA that occurs when it is heated. The phase transformation completion temperature of the SMA that we used is 55°C. To prevent the SMA from being overheated in a living body, a transformer utilizing thermosensitive ferrite is used as a temperature control device. In an earlier prototype, we confirmed that temperature control of the SMA was possible. We examined suitable core design and composition. The transformer core type is composed of a hybrid core that uses thermosensitive Ni-Cu-Zn ferrite (Curie-point Tc = 60°C) and non-thermosensitive Mn-Zn ferrite. Effective saturation magnetic flux density of the thermosensitive ferrite and the Mn-Zn ferrite are 250 mT and 520 mT respectively at room temperature. Class 10 W power transmission is possible through this small transformer. When the temperature of the SMA is higher than Tc, magnetization of the thermosensitive ferrite disappears and power transmission to the heater weakens.

The implanted device targeted here is an artificial sphincter that utilizes a shape memory alloy (SMA). It receives drive energy through a transcutaneous energy transmission system which utilizes the electromagnetic coupling of a coil pair. This artificial sphincter bends according to the metamorphosis of the SMA. Temperature control in the living body is necessary to heat the SMA to its metamorphosis-completion temperature. Taking advantage of the lack of need for a power supply for the sensor drive, we examined a method of controlling electric power to be transmitted by a control transformer consisting of a thermosensitive magnetic ferrite core. The temperature of the SMA is controlled by referring the Curie point of the ferrite attached to the SMA. The metamorphosis-completion temperature of the SMA that we used is 55°C. The purpose of this system is automatic prevention of SMA overheating when the SMA temperature rises to 55°C. Actually, because the electric power transmitted through the transformer decreases smoothly with a rise in temperature around the Curie point, the temperature of the SMA stabilizes at a balance point where the heat radiation of the SMA balances overheating by the heater.

Wide Area Multilateration (WAM) is a useful aeronautical surveillance system which is able to achieve high performance. However, WAM has a drawback in which position errors increase rapidly outside a constellation of receiver stations in principle. One of the solutions for the drawback is to apply a measured range between a receiver station and an aircraft to the Time Difference of Arrival (TDOA) localization. This paper describes test results of performance evaluation for a WAM experiment system using the measured range.

A temperature and output power control transformer that is applied to an implanted device called artificial sphincter that is composed of shape memory alloy (SMA) is examined. The artificial sphincter is using phase transformation of SMA depending on temperature. To prevent overheating, we examined temperature control utilizing thermosensitive magnetic ferrite. As the temperature rises, the power decreases that is conveyed through the transformer that uses thermosensitive ferrite as its core. If the heater attached to SMA is provided with the electric power through the transformer, it is possible to control the temperature of SMA.

The implanted device discussed here is an artificial sphincter that utilizes shape memory alloy (SMA). To provide an independent evacuation for the patients using artificial anus, this device is implanted into their body. It receives driving energy by a transcutaneous energy transmission system using an electromagnetic coupling of a coil pair. This artificial sphincter operates according to the phase transformation of the SMA. Temperature control in the living body is necessary in order to heat the SMA to its phase transformation completion temperature. Taking advantage of the needless of a power supply for the temperature control circuit, we examined the way of controlling electric power to be transmitted by the transformer consisting of thermosensitive magnetic ferrite core. The SMA temperature is controlled by using the Curie-point of the ferrite attached to SMA as a reference temperature. Phase transformation completion temperature of the SMA that we used is 55/spl deg/C. The purpose of this system is to automatically prevent overheating of the SMA above 55/spl deg/C. Actually, because the electric power transmitted through the transformer decreases smoothly as the temperature rises to the Curie-point, the temperature of the SMA becomes stable to a point at which the heat conduction of the SMA balances the heat generated by the heater.

As the heart failure is caused by the decrease in the myocardial contraction, the direct mechanical myocardial assistance in response to physiological demand, that is, the synchronous support of the contractile function from outside of the heart, might be effective. The purpose of this study was to develop an artificial myocardium which was capable of supporting the cardiac contraction directly by using the shape memory alloy fibres based on nanotechnology. Some methodologies using novel devices other than the artificial hearts are proposed so far with severe heart disease. However, it was also anticipated that the decrease in cardiac functions owing to the diastolic disability might be caused by using those ‘static’ devices. Then, this study was focused on an artificial myocardium using shape memory alloy fibres with a diameter of 100 – 150 um, and the authors examined its mechanism in a mock circulatory system as well as in animal experiments using goats. Basic characteristics of the material were evaluated prior to the hydrodynamic or hemodynamic examination using a mock ventricular model. The results were as follows: a) The length of the structure was able to be adjusted so that the system could wrap the whole heart effectively. b) In the hydrodynamic study using the mock circulatory system, the myocardial system was able to pump a flow against the afterload of arterial pressure level. c) In the animal experiments, aortic pressure and flow rate were elevated by 7 and 15% respectively by the mechanical assistance of the artificial myocardium, which was driven synchronising with the electrocardiogram, and also, d) The anatomically-identical shape of the artificial myocardium might be more effective for the assistance. In conclusion, it was indicated that this controllable artificial myocardial support system was effective for the mechanical cardiac support for the chronic heart failure.

In this work, a small inductor using magnetic property depending on temperature, and transcutaneous temperature control system was proposed. The artificial anal sphincter is actuated by flexible heaters attached to SMA, then opens anal canal. The purpose of this study is to propose the simple system of artificial sphincters controlled its temperature by the inductor consisting of Ni-Cu-Zn based thermosensitive magnetic ferrite. In this paper, a prototype of thermosensitive inductor is designed for evaluations, and tested it to confirm the temperature controllability in order to prevent the SMA from overheating.

Heart transplantation is currently the best treatment for end-stage heart failure. There is a large disparity between the number of available donor hearts and the number of people who need them. Total artificial hearts and ventricular assist devices have been developed as alternatives to the transplantation. Percutaneous leads should be avoided in long-term implantations due to the risk of infection and the restraint on patients' activities. Transcutaneous energy transmission systems transmit electric power across intact skin by electromagnetic induction with a pair of coils. Our system has thin ferrite cores, which increase the magnetic coupling factor and self-inductance. In addition MOSFET synchronous rectifier using a digital PLL technique can reduce forward voltage drops. These features result in high energy transmission efficiency. Also the core has a roll of magnetic shield. This effect made it possible to mount the synchronous rectifier circuit board on the back of the coil. In animal experiments, the output voltage of the TETS decreased when the primary coil shifted from the normal position. Local elevations of temperature at the ICs that consume relatively high power caused heat injuries. Also pressure necroses were seen in the circumference of the secondary coil.

The authors have been developing an artificial myocardium using a sophisticated covalent shape memory alloy fibre, which is capable of assisting natural cardiac contraction from the outside of the ventricular wall. We applied engineering method based on robotics control and constructed the artificial myocardial assist system which might be able to regulate derangement and regenerative tensile force on the surface of heart. In this study, a design to surround the total heart has been established in order to refrain from the stress concentration by the mechanical assistance, and the hemodynamic performance of the artificial myocardial assist system were examined in a mock circulatory system as well as on animal experiments using goats. Basic characteristics of the shape memory alloy fibre unit were examined and the displacement control could be achieved under the condition of the different external temperature by feedback using the PID control. And also the increase of the external work of the goats left ventricular pressure-volume relationship were obtained by the assistance using an artificial myocardium with parallel-linked configuration, and therefore it was indicated that the effective ventricular mechanical support could be performed by the device.

To realize the temperature control for implanted medical device called artificial anal sphincter utilizing shape memory alloy (SMA) board, a small transformer is made as a control device that consists of thermosensitive ferrite core. Thermosensitive transformer can transmit the electric power to the load heater at the temperature under Curie-point of the thermosensitive ferrite, and can intercept the power at the temperature over Curie-point. Then the power control depending on temperature can be realized. At the device applying only the temperature dependence of magnetic property, a machine trouble rarely happens, so the device can be used safely in a living body. The heat transmission property of the ferrite core was not quite suitable as a thermosensitive device. In this examination, the power loss at the magnetic core is regulated, and the heat transmission property is equivalently improved. Then a long time control of the SMA temperature is confirmed.