it is expected that the processing performance can be improved from the processor
architecture point of view. These topics are discussed next.
Satellites should be smart even in the harsh environment. They are operated by
remote control from the ground stations on the Earth. Distance and round-trip
communication time of typical satellites to the Earth are shown in Fig. 7. As the
distance becomes longer, the more communication delay time must be considered.
As for the example of a deep space probe HAYABUSA, the round-trip communication time was 34 min, and it was difficult to operate the satellite in real time by
remote control. Therefore, the satellite must work in itself by using radiation
hardened semiconductor devices for microprocessors and memory devices. In addition to that, such satellites have many sensors in them. Transmission capacity of
communication channels between ground stations on the Earth and satellites are
limited, and onboard data manipulations such as data selection and data compression
are required to make the best use of limited transmission capacity.
Examples of satellites with sensors and edge computing functions are shown in
Fig. 8. Those satellites equipped with several sensors for various wavelengths, such
as visible light, infrared and ultraviolet. The sensor system must have signal
preprocessing functions to get high quality data of these spectra through the limited
capacity of transmission channels towards ground stations. A high-speed data
compression is one of the most needed function. Combinations of FPGAs and
MCUs are employed to transmit high quality for those implementations, because
radiation hardened MCUs are not high speed enough to compress data using the
latest algorithm. AKATSUKI [14], the Venus Climate Orbiter, and HAYABUSA2
[15], the asteroid probe are shown in Fig. 8a, and Fig. 8b respectively. High speed
data compression has been realized using the combination of an MCU and FPGAs
with distributed memories. Image recognition functions and signal calibration functions are also implemented on HAYABUSA2 by using the combination of an MCU
and FPGAs with distributed memories as well.
HAYABUSA
Himawari (GMS)
36,000km
700km
Round trip communication
time
Daichi (ALOS)
300,000,000km
The Earth
240 ms
34 min,
with invisible period
Distance
0
5 ms,
with invisible period
© JAXA
Fig. 7 Distance and round-trip communication time of typical satellites between the Earth
42
H. Hihara et al.
architecture point of view. These topics are discussed next.
Satellites should be smart even in the harsh environment. They are operated by
remote control from the ground stations on the Earth. Distance and round-trip
communication time of typical satellites to the Earth are shown in Fig. 7. As the
distance becomes longer, the more communication delay time must be considered.
As for the example of a deep space probe HAYABUSA, the round-trip communication time was 34 min, and it was difficult to operate the satellite in real time by
remote control. Therefore, the satellite must work in itself by using radiation
hardened semiconductor devices for microprocessors and memory devices. In addition to that, such satellites have many sensors in them. Transmission capacity of
communication channels between ground stations on the Earth and satellites are
limited, and onboard data manipulations such as data selection and data compression
are required to make the best use of limited transmission capacity.
Examples of satellites with sensors and edge computing functions are shown in
Fig. 8. Those satellites equipped with several sensors for various wavelengths, such
as visible light, infrared and ultraviolet. The sensor system must have signal
preprocessing functions to get high quality data of these spectra through the limited
capacity of transmission channels towards ground stations. A high-speed data
compression is one of the most needed function. Combinations of FPGAs and
MCUs are employed to transmit high quality for those implementations, because
radiation hardened MCUs are not high speed enough to compress data using the
latest algorithm. AKATSUKI [14], the Venus Climate Orbiter, and HAYABUSA2
[15], the asteroid probe are shown in Fig. 8a, and Fig. 8b respectively. High speed
data compression has been realized using the combination of an MCU and FPGAs
with distributed memories. Image recognition functions and signal calibration functions are also implemented on HAYABUSA2 by using the combination of an MCU
and FPGAs with distributed memories as well.
HAYABUSA
Himawari (GMS)
36,000km
700km
Round trip communication
time
Daichi (ALOS)
300,000,000km
The Earth
240 ms
34 min,
with invisible period
Distance
0
5 ms,
with invisible period
© JAXA
Fig. 7 Distance and round-trip communication time of typical satellites between the Earth
42
H. Hihara et al.