The primary purpose of QZSS is to increase the availability of GPS in Japan's numerous urban canyons, where only satellites at very high elevation can be seen.

QZSS is a four-satellite system that provides regional communication services and positioning information for the mobile environment. The focus of this system is for the Japan region, but it will provide service to the Asia-Oceania region.

Satellite positioning systems use satellite signals to calculate position information. One famous example is the American Global Positioning System (GPS); the QZSS is sometimes called the “Japanese GPS.”

Explanation: Japan is a country that has its own satellite navigation system. The system is called the Quasi-Zenith Satellite System (QZSS) and it is designed to augment the existing GPS system, providing more accurate and reliable positioning and timing information within Japan and surrounding regions.