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Mitsubishi Electric Corporation
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www.MitsubishiElectric.com/news/“DAICHI-4” ALOS-4 Satellite Acquires First Observation Images
World-class satellite’s wide-area, high-resolution images will support disaster prevention and mitigation

First observation image from the DAICHI-4 (courtesy JAXA)TOKYO, August 6, 2024 – Mitsubishi Electric Corporation (TOKYO: 6503) announced today that the firstobservation images have been acquired in a radio-irradiation test conducted with the Phased Array type Lband Synthetic Aperture Radar-3 (PALSAR-3) on board the Advanced Land Observing Satellite-4 “DAICHI4” (ALOS-4). The satellite, manufactured by Mitsubishi Electric under contract from the Japan Aerospace
Exploration Agency (JAXA), was launched at 12:06:42 (Japan Standard Time) on July 1 aboard the third H3
Launch Vehicle from Tanegashima Space Center in Japan.
The new satellite’s PALSAR-3 radar beams radio waves to Earth’s surface and receives the reflected waves
that are used to produce high-resolution images over wide areas. This capability will enable rapid monitoringof disaster-stricken areas, including in the event of multiple natural disasters over a wide area. Mitsubishi
Electric began developing the DAICHI-4 in 2017 and was responsible for overall designing, manufacturing

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and testing at its Kamakura Works in Japan. The company also developed the PALSAR-3 radar for wide-area,
high-resolution observations.
PALSAR-3 achieves the same level of high-resolution images as the radar on board the “DAICHI-2” (ALOS2), but is also capable of wider, global-scale high-precision observations from an altitude of about 628 km. It
will be used to monitor crustal and ground deformation, enabling early detection of abnormalities such as
volcanic activity, ground deformation and landslides, as well as support more efficient management of forest
resources.
Mitsubishi Electric continues to leverage its well-established expertise to develop and manufacture satellites
as well as utilize satellite data to help address critical issues in society.

Rendition of DAICHI-4 (courtesy JAXA)DAICHI-4 mission mark (courtesy JAXA)

Product Features
1)

High-resolution, wide-area observations using new radar developed with new methods and technologies- The DAICHI-4 adopts the world’s first1 multiple transmit channel technology that transmits signals ofdifferent frequencies from different areas of the antenna and then combine the signals upon reception.
- While maintaining the DAICHI-2’s 3-meter resolution, the DAICHI-4 is the world’s first1 radar satellite todeploy digital beamforming technology, which uses onboard high-speed computing to generate arbitrary
beam directions for an observation swath extended to a top-level 200km, four times that of the DAICHI-2.
- Acquisition of wider-area imagery with single observations accelerates information collection
following wide-area disasters.
- High output power of the radar is achieved using Mitsubishi Electric’s top-level high-power gallium nitride(GaN) amplifier, which has been proven in the DAICHI-2, enabling the DAICHI-4 to maintain imagequality even with its expanded observation swath.

1As a practical satellite, according to Mitsubishi Electric research as of August 6, 2024

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Observation swaths of DAICHI-2 (left) and DAICHI-4 (courtesy JAXA)

3m-resolution, 200km-wide images acquired by PALSAR-3, showing Mt. Fuji (left) and upper Tokyo Bay (courtesy JAXA)

2)

More frequent observations due to wider swath contribute to disaster prevention and mitigation- The DAICHI-4’s wider swath capability enables observations of whole locations across Japan 20 times
per year, which is substantially greater than four observations with DAICHI-2.
- When a disaster occurs, the DAICHI-4 can be switched from normal to emergency observation tocompare data obtained immediately before and after the disaster, enabling changes to be identified andanalyzed to quickly grasp the situation in the affected area. Data across Japan can be continuously andfrequently updated, contributing to faster and more accurate assessment of disasters.
- The increased frequency of observations will enable more periodic monitoring across Japan, which isexpected to contribute to earlier and multiple detection of abnormal changes, such as ground and crustaldeformation.

3)

Enhanced transmission rate with Ka-band direct transmission system2- The Ka-band direct data transmission system developed under “DAICHI-3” (ALOS-3) has beenenhanced to support the DAICHI-4 mission. The transmission data rate of the DAICHI-4 is 3.6 Gbps,
4.5 times3 higher than that of the DAICHI-2’s X-band system, which is the world’s highest4
performance for an earth observation satellite.
- For both normal and post-disaster emergency observations, large amounts of observation data can berapidly transmitted to the ground.

A method of sending data directly from the satellite to the groundFor dual-frequency transmissions
4According to Mitsubishi Electric research as of August 6, 2024
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Main Specifications
Dimensions (in orbit)
Mass
Power generation
Electricity
Battery capacity
Transmission rate
Storage capacity
Resolution
Spotlight mode
Swath
Resolution
Observation
Stripmap mode
performance
Swath
Resolution
ScanSAR mode
Swath
Orbit
Design life

10.0m×20.0m×6.4m
approx. 3,000kg
approx. 7,000W
380Ah
3.6Gbps (Ka-band)
approx. 1Tbyte
1m×3m
35km×35km
3m, 6m and 10m200kmmax. 25m
700km
628km
7 years

Mitsubishi Electric’s Space Business
Mitsubishi Electric, a leader in Japan’s space development, has participated as a prime contractor in nearly
half of JAXA’s satellite-development projects. Going forward, Mitsubishi Electric will continue to enhance its
advanced technologies and space business to contribute to greater sustainability and resilience in society forincreased prosperity.
###About Mitsubishi Electric Corporation
With more than 100 years of experience in providing reliable, high-quality products, Mitsubishi ElectricCorporation (TOKYO: 6503) is a recognized world leader in the manufacture, marketing and sales of electricaland electronic equipment used in information processing and communications, space development and satellite
communications, consumer electronics, industrial technology, energy, transportation and building equipment.
Mitsubishi Electric enriches society with technology in the spirit of its “Changes for the Better.” The company
recorded a revenue of 5,257.9 billion yen (U.S.$ 34.8 billion*) in the fiscal year ended March 31, 2024. For
more information, please visit www.MitsubishiElectric.com*U.S. dollar amounts are translated from yen at the rate of ¥151=U.S.$1, the approximate rate on the Tokyo
Foreign Exchange Market on March 31, 2024

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