# Michibiki 4

> Japanese navigation satellite

**Wikidata**: [Q45978054](https://www.wikidata.org/wiki/Q45978054)  
**Source**: https://4ort.xyz/entity/michibiki-4

## Summary
Michibiki 4 is a Japanese navigation satellite launched on October 9, 2017, as part of Japan's Quasi-Zenith Satellite System (QZSS) for enhanced GPS coverage in the Asia-Oceania region. It was built by Mitsubishi Electric and launched aboard an H-IIA rocket from Tanegashima Space Center. The satellite provides positioning, navigation, and timing services with a mass of 4,000 kg.

## Key Facts
- Launched on October 9, 2017, aboard H-IIA-36 rocket from Tanegashima Space Center
- Satellite mass: 4,000 kg (dry mass: 2,360 kg)
- Part of Japan's Quasi-Zenith Satellite System (QZSS) for regional GPS augmentation
- Built by Mitsubishi Electric Corporation
- Operated by the Japan Aerospace Exploration Agency (JAXA)
- Orbital period: 2.85 hours
- Satellite dimensions: 6.2 meters in length
- Satellite designation: QZS-4, QZSS-4, QZS4
- International Designator: 2017-062A
- NORAD Catalog Number: 42965

## FAQs
### Q: What is Michibiki 4's purpose?
A: Michibiki 4 is a navigation satellite that enhances GPS coverage and reliability in the Asia-Oceania region as part of Japan's Quasi-Zenith Satellite System. It provides positioning, navigation, and timing services to improve location accuracy and availability.

### Q: When and how was Michibiki 4 launched?
A: Michibiki 4 was launched on October 9, 2017, aboard an H-IIA-36 rocket from the Tanegashima Space Center in Japan. The launch was conducted by Mitsubishi Heavy Industries.

### Q: Who operates Michibiki 4?
A: Michibiki 4 is operated by the Japan Aerospace Exploration Agency (JAXA) on behalf of the Government of Japan. The satellite provides services for both commercial and government applications.

## Why It Matters
Michibiki 4 plays a crucial role in Japan's strategy for autonomous navigation and positioning capabilities. As part of the QZSS constellation, it provides enhanced GPS coverage specifically tailored for the Asia-Oceania region, addressing the unique challenges of mountainous terrain and urban canyons in Japan where standard GPS signals can be obstructed. The satellite's services are vital for various applications including disaster management, autonomous vehicle navigation, precision agriculture, and maritime operations. By providing more reliable positioning data, Michibiki 4 contributes to Japan's technological sovereignty and economic competitiveness in the global satellite navigation market. The system also serves as a backup to GPS, enhancing national security and emergency response capabilities.

## Notable For
- First QZSS satellite to provide L6 signal for commercial applications
- Enhanced GPS coverage specifically optimized for Japan's challenging terrain
- Part of Japan's first independent regional navigation satellite system
- Provides centimeter-level positioning accuracy when combined with ground-based augmentation
- Supports both safety-of-life and commercial navigation services

## Body
### Technical Specifications
Michibiki 4 features a three-axis stabilized design with a launch mass of 4,000 kg and a dry mass of 2,360 kg. The satellite measures 6.2 meters in length and operates in a highly inclined geostationary orbit with a period of 2.85 hours. It carries multiple navigation payloads including L1, L2, L5, and L6 signals for different applications.

### Mission Profile
The satellite operates as part of a constellation that includes three other QZSS satellites, providing continuous coverage over Japan and surrounding regions. Its orbit is specifically designed to maximize visibility in urban areas and mountainous regions where traditional GPS signals may be obstructed. The system provides both standalone navigation services and augmentation to GPS signals.

### Operational Capabilities
Michibiki 4 provides several key services:
- Centimeter-level augmentation service (CLAS) for high-precision applications
- Quasi-zenith satellite system standard service (QZSS) for general positioning
- Safety confirmation service (SCS) for disaster management
- L6 signal for commercial and research applications

### Ground Segment
The satellite is supported by a network of ground control stations across Japan, including the main control center in Tokyo. These facilities monitor satellite health, manage orbital maneuvers, and coordinate with other QZSS satellites to maintain system integrity and service availability.

## References

1. [Source](https://space.skyrocket.de/doc_sdat/qzs-2.htm)
2. Jonathan's Space Report
3. [Source](https://qzss.go.jp/en/technical/qzssinfo/khp0mf0000000wuf-att/spi-qzs4_c.pdf)