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Hayabusa2, the first sample return mission to a C-type asteroid was launched by the Japan Aerospace Exploration Agency (JAXA) on December 3, 2014 and will arrive at the asteroid in the middle of 2018 to collect samples from its surface, which may contain both hydrated minerals and organics. The optical navigation camera (ONC) system on board the Hayabusa2 consists of three individual framing CCD cameras,...
Recently, utilization of position information by global navigation satellite system (GNSS) is expected in various fields. However, it's difficult to show unambiguously accuracy since positioning accuracy varies by measurement environment. We bring sky view factor (SVF) to evaluation of positioning accuracy, and evaluate it positioning accuracy of long time data in the places where SVF are high or...
In the machine to machine (M2M) propagation environment, beam direction changing technique for small antenna like dipole antenna size is required. We proposed to adopt meta-surface to achieve this instead of reflectarray. However, study of beam switching for meta-surface is not enough despite of important for mobile M2M. To address the issue, this paper proposes novel reflected beam switching method...
This paper proposes novel design method of dualband reflectarray using genetic algorithm (GA). Ordinary, each elements of reflectarray are designed to have desired reflection phase. However, when we adopt same polarization in dual frequencies, the element configuration designed to satisfy desired reflection phase in one frequency influences the characteristics in other frequency. Therefore, it is...
In this paper, we describe the configuration of a direct RF undersampling receiver and demonstrate the demodulation characteristics of QPSK signal for Ka-Band VSAT (Very small aperture terminal). Two different clock (CLK) sources are used to compare the difference of CLK jitter effect on the EVM. In the case of the received RF frequency is 19.4GHz and the CLK frequency is 808MHz (24th undersampling)...
In the machine to machine (M2M) communication, the propagation environment is worse than that of usual mobile communications, because the terminal equipment is installed in niche space, such as a gap between pieces of furniture. One solution to cope with the bad condition is to apply a high spec antenna, however, it is difficult to change antenna specification because in most cases it should comply...
We propose an image rejection type direct RF undersampling receiver. By using a direct RF I/Q sample and hold (S/H) circuits, and 90 degree power combiners in the digital domain, upper side band (USB) and lower side band (LSB) signals can be separated into two different (USB and LSB) output ports, therefore the image rejection functionality can be realized with half of the clock frequency of the conventional...
The optical navigation camera telescope (ONC-T) is a telescopic framing camera with seven colors onboard the Hayabusa2 spacecraft launched on December 3, 2014. The main objectives of this instrument are to optically navigate the spacecraft to asteroid Ryugu and to conduct multi-band mapping the asteroid. We conducted performance tests of the instrument before its installation on the spacecraft. We...
Direct RF under sampling reception has been developed to reduce the size and the power consumption of the terrestrial wireless terminals. We applied this reception method to Ku-band very small aperture terminal (VSAT). In this paper, we develop a CMOS sample and hold (S/H) IC for Ka-band VSAT receiver. Since Ka-band VSAT requires higher RF frequency operation (19.4–20.2 GHz) and wider system bandwidth...
The Hayabusa2 spacecraft has three framing cameras (ONC-T, ONC-W1, and ONC-W2) for optical navigation to asteroid 1999 JU3. The ONC-T is a telescopic camera with seven band-pass filters in the visible and near-infrared range. These filters are placed on a wheel, which rotates to put a selected filter for different observations, enabling multiband imaging. Previous ground-based observations suggesting...
In the event of large scale disaster such as the great east Japan earthquake, we completely lose the terrestrial communication infrastructure and have no measure to call the outside of the disaster area. Satellite communication is only an exception and can be usable in such a situation. In this project, funded by the Ministry of Internal Affairs and Communication (MIC), Japan, we have developed a...
This paper presents a multi-band receiver front-end IC in 90nm CMOS technology. The receiver front-end IC is switchable between a 5GHz front-end and a 60GHz front-end. The architecture of the receiver front-end IC is a direct conversion in 5GHz band and a superheterodyne in 60GHz band. For the miniaturization, the 5GHz and 60GHz front-ends share a variable gain amplifier for adjustment of power level...
This paper presents an flip-chip assembled 60GHz CMOS receiver front-end. The receiver front-end consists of a cascode LNA, a balun, a harmonic mixer, and an IF amplifier fabricated by 90nm CMOS. The flip-chip assembled cascode LNA performs 31.1dB gain as well as on-wafer probing with NF of 5.8dB and output P1dB of −3.9dBm at 60GHz while consuming 26.9mW. The flip-chip assembled receiver front-end...
Laser-induced breakdown spectroscopy (LIBS) is a very useful elemental analysis tool in planetary exploration. In this study we conduct LIBS measurements under low pressure (1×10−3 mbar) to investigate the feasibility of LIBS measurement under vacuum conditions. Although the optical emission intensity decreases remarkably under low ambient pressure, our preliminary experimental results indicate that...
Pulsed streamers in highly pressurized carbon dioxide up to and including the supercritical state were observed by means of Schlieren method. The fluid temperature was set to T = 305 K; pressures, to P = 7.5 and 8.0 MPa. The gap was needle-to-plane; the gap lengths in positive and negative were d = 7 and 1 mm, respectively. Pulse voltages of positive/negative polarity generated by a magnetic pulse...
This paper deals with visualization of positive pulsed streamers and arc discharge under a needle-to-plane gap in supercritical carbon dioxide (SCCO2) by the Schlieren Method. In addition, differences in streamer branches in gas, liquid and supercritical phases of CO2 are evaluated by means of fractal dimension. The experimental results are summarized as follows: 1) a tree-like streamer growing from...
This paper proposes a heterogeneous wireless communication network with soft handover in the application layer. The proposed network requires no upgrades of wireless infrastructure and mobile terminals to evolve the present homogeneous networks to the proposed heterogeneous network. Only installing application programs on the content server side and the mobile terminal side is required. The performance...
We propose a 5 GHz-band 3-stacked MLA integrated with a meander-line shape balun using multi-layered substrates. Return loss and actual gain are evaluated by 3D electromagnetic simulation and measurement. As a result, relative bandwidth of 2.4% and actual gain of -1.5 dBi at 5.0 GHz are measured. Cross polarization gain of more than 30 dB can be suppressed compared to co-polarization in the desired...
In this paper, we report on a mobile broadband wireless access (MBWA) system field trial with Fast Low-latency Access with Seamless Handoff Orthogonal Frequency Division Multiplexing (FLASH-OFDM). This paper describes coverage estimates of an uplink 64 quadrature amplitude modulation (QAM) signal under the condition of constant terminal output power when the signal bandwidth is up to 20 MHz. The estimates...
In this paper, we report on a mobile broadband wireless access (MBWA) system field trial with Fast Low-latency Access with Seamless Handoff Orthogonal Frequency Division Multiplexing (FLASH-OFDM), which was carried out at Sendai city in Japan. This paper describes coverage estimates of an downlink 64 quadrature amplitude modulation (QAM) signal under the condition of constant base-station output power...
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