Takahide Mizuno

A high-speed downlink communication system is required to meet various applications for nano/small satellites. Therefore, it is essential to implement a transmitter with small weight and power in such satellites. We have developed high speed communication system over 300 Mbps for small satellite. In order to reduce DC power consumption of transmitter, we have developed GaN-HEMT power amplifier for X band downlink. The Hodoyoshi-4 satellite equipped with the developed communication system was launched in 2014 and we demonstrated 348 Mbps downlink from 50-kg class satellite. This paper describes the summary of the developed system, the experiment of high speed downlink, and future works.

A high-speed downlink communication system is required to meet various applications for nano/small satellites. Therefore, it is essential to implement a transmitter with small weight and power in such satellites. We have developed high speed communication system over 300 Mbps for small satellite. In order to reduce DC power consumption of transmitter, we have developed GaN-HEMT power amplifier for X band downlink. The Hodoyoshi-4 satellite equipped with the developed communication system was launched in 2014 and we demonstrated 348 Mbps downlink from 50-kg class satellite. This paper describes the summary of the developed system, the experiment of high speed downlink, and future works.

A high-speed downlink communications system is required to meet various applications for nano/small satellites. It is essential to implement a transmitter with small weight and power in such satellites. We have developed a compact 348Mbps transmitter incorporating a powerful error correction on ground station receiver. This system has been demonstrated a high-speed down link communication system at "Hodoyoshi-4" satellite with 50 kg mass.

Recently small satellites play important roles in earth observations with medium resolution. This purpose requires a small earth station which is equipped with S band up/down satellite operation functions as well as with X band high data rate reception functions. We have developed a small earth station with a 3.8 m antenna and evaluated them with relatively low cost. This paper describes the cost-effective test method and the results.

We review the current status and future plans in laser ranging from/to the Earth to a Japanese planetary mission Hayabusa-2. A limited hardware on board and experimental windows being given, configuration of ranging two-way, one-way up/down link assuming station capable of 1 micron ranging is considered from the perspective of accuracy, detection probability. Issues with the requirements of the specifications and required as a ground station request ,as well as international cooperation station for the angle measurement will be discussed.

A high-speed downlink communication system is required to meet different applications for nano/small satellites. Therefore, it is essential to implement a power- and weight-limited transmitter in such satellites. Our recent research has focused on an efficient system adopting CCSDS 131.0-R signaling formats with the limited transmitter incorporating a powerful ground station receiver. To overcome signal distortion at the cost of some limitations of the transmitter, an SCCC turbo equalization system equipped with nonlinear distortion compensation techniques in the receiver has been developed. We simulate the system using practical distortion models to determine the performances of BER and synchronization.

In recent years, small/nano satellites have been developed by universities and companies to utilize space environments. A high speed downlink communication system for small/nano satellites is required to realize different kind of applications. We have developed the effective system which is adopted a low complexity satellite transmitter incorporating a powerful earth station receiver. To overcome same distortions due to the low complexity, turbo equalization is essential for the receiver. We then developed a nonlinear distortion compensation and a blind converge detector for the turbo equalization. This paper presents the concept of the communication system, the principle of these techniques, and the simulation results.

The Institute of Space and Astronautical Science JAXA is developing a landing radar comprising a radio altimeter and a velocity meter, which are two of the mandatory navigation sensors for a planetary Lander. A BBM of the landing radar has been evaluated on natural terrains by using a helicopter. This paper introduces the BBM hardware and discusses the dynamic performance in field experiments.

For scientific observation using a lunar and a planetary lander, a pinpoint landing technology whose ambiguity is less than 100m must be needed for landing system. A landing radar that measures an altitude and velocity of a space craft with microwave is very important navigation sensor to realize the pinpoint landing. It is a mandatory sensor for any future missions of planetary landing. This report describes the poroblems of the landing radar BBM in short range measurement.