GLONASS (Globalnaya Navigazionnaya Sputnikovaya Sistema, or Global Navigation Satellite System) is Russia’s global satellite navigation system, providing worldwide positioning, navigation, and timing services comparable to the United States’ GPS. Developed originally by the Soviet Union with the first satellite launched in 1982, GLONASS achieved initial operational capability in 1993 and has been maintained and modernized by the Russian Federation as critical national infrastructure.

The GLONASS constellation consists of 24 satellites distributed across three orbital planes inclined at 64.8 degrees to the equator, at an altitude of approximately 19,100 kilometers. This relatively high orbital inclination provides superior satellite visibility at high latitudes compared to GPS, making GLONASS particularly valuable for users in northern regions of Russia, Scandinavia, Canada, and Alaska. The complete constellation ensures that users worldwide can typically observe six to eight GLONASS satellites simultaneously.

A notable technical distinction of GLONASS from other GNSS constellations is its historical use of Frequency Division Multiple Access (FDMA), where each satellite broadcasts on slightly different frequencies. This contrasts with the Code Division Multiple Access (CDMA) approach used by GPS, Galileo, and BeiDou, where satellites share common frequencies but use unique spreading codes. Modern GLONASS-K satellites also broadcast CDMA signals for improved interoperability with other constellations, while maintaining legacy FDMA signals for backward compatibility.

For GNSS users worldwide, GLONASS integration provides significant benefits regardless of geographic location. Multi-constellation receivers tracking both GPS and GLONASS satellites can access roughly 50% more satellites than GPS-only receivers, improving positioning geometry, reducing time-to-first-fix, and enhancing availability in challenging environments. GLONASS signals are freely available for civil use, and the system’s independence from GPS provides redundancy against single-constellation failures or interference, making GLONASS an essential component of robust multi-constellation positioning solutions.