Comparing the coverage and accuracy of the Japanese QZSS and the Chinese Beidou navigation systems
If you own a smartphone or car with a built-in GPS system, you are probably familiar with the Global Positioning System (GPS) developed by the United States. However, other countries have developed their own satellite navigation systems, including Japan's Quasi-Zenith Satellite System (QZSS) and China's BeiDou Navigation Satellite System (BDS).
Both the QZSS and BDS were created to reduce reliance on GPS, as well as to provide additional coverage and accuracy in areas not covered by GPS. In this article, we will compare the coverage and accuracy of these two systems.
Coverage
The QZSS consists of four satellites that orbit in a highly elliptical orbit north of Japan. The satellites have been specifically designed to improve coverage in urban canyons and mountainous areas where GPS signals may have difficulty penetrating. As a result, QZSS provides better coverage in these regions, and in some cases, can even reach areas that are not covered by GPS. However, the coverage is still mostly limited to Japan and its surrounding regions.
On the other hand, the BDS is a global navigation system that currently has over 30 satellites in orbit. The system provides coverage to the Asia-Pacific region and some parts of Africa and Europe. There are plans to expand the system to a global scale by 2020.
Thus, if you are traveling outside of Japan and the Asia-Pacific region, then the BDS system may be a better option.
Accuracy
The accuracy of any navigation system depends on various factors such as the number of satellites in orbit, the type of signals transmitted, and the distance between the receiver and the satellites.
Both the QZSS and BDS systems use similar signals and frequencies as GPS, but the QZSS system broadcasts an additional signal that improves the accuracy of the system. As a result, the accuracy of QZSS is about 1 meter - which is slightly better than GPS - while the accuracy of BDS is about 5 meters.
However, it is worth noting that the accuracy can be affected by the environment around the receiver, such as buildings, mountains, and trees. Therefore, it is difficult to determine which system is more accurate in all situations.
Conclusion
In conclusion, both the QZSS and BDS systems provide additional coverage and accuracy in regions not covered by GPS. If you are in Japan, then the QZSS system may be a better option due to its improved coverage and accuracy. If you are traveling outside of Japan and the Asia-Pacific region, then the BDS system may be a better option.
But whichever system you choose, you can be assured that you will always be able to find your way - unless the satellites are down, in which case, good luck with that.
References:
- Quasi-Zenith Satellite System: https://qzss.go.jp/en/
- BeiDou Navigation Satellite System: http://en.beidou.gov.cn/