Detailed Explanation:

Answer: Option 4 — Japan

Japan operates the QZSS (Quasi-Zenith Satellite System), which is a regional satellite navigation system designed to enhance GPS coverage and accuracy in the Asia-Oceania region, particularly over Japan. Among the given options, only Japan has its own satellite navigation system.

📝 Short Notes: Satellite Navigation Systems Worldwide

• Global Navigation Satellite Systems (GNSS): Four operational systems - GPS (USA), GLONASS (Russia), Galileo (European Union), and BeiDou (China) - provide worldwide coverage.
• Regional Navigation Satellite Systems: NavIC/IRNSS (India) covers Indian subcontinent and surrounding region up to 1,500 km; QZSS (Japan) enhances GPS signals in Asia-Oceania region.
• GPS (USA): First operational GNSS with 24+ satellites, launched in 1978, fully operational since 1995.
• GLONASS (Russia): Developed during Soviet era, fully operational since 2011 with 24+ satellites.
• Galileo (EU): European system providing high-precision positioning, became operational in 2016.
• BeiDou (China): Completed global coverage in 2020 with 35 satellites, serves both regional and global users.
• NavIC (India): Indian Regional Navigation Satellite System with 7 satellites, operational since 2018, provides positioning accuracy better than 20 meters.
• QZSS (Japan): Quasi-Zenith Satellite System with satellites in quasi-zenith orbits, providing enhanced positioning over Japan and neighboring regions.