Apple Watch Ultra 4 drops GLONASS satellite support, keeping GPS, Galileo, QZSS and BeiDou

The Apple Watch Ultra 4 has been found to drop support for the GLONASS satellite system from the technical specifications Apple officially published, while still supporting GPS, Galileo, QZSS, and BeiDou — unlike the Apple Watch Ultra 3, which supported all 5 systems.

GLONASS is Russia's navigation system, which most consumer devices can only receive via the L1 signal, less accurate than other systems, especially on dual-frequency devices like the Ultra 4. GLONASS also uses a different signal architecture, requiring receivers to adjust hardware delay values per satellite, which can introduce positioning errors.

Apple has not officially explained the reason, but experts believe dropping it likely improves accuracy, reduces processing load, and may benefit battery life. The Apple Watch Series 12, being single-frequency, still keeps GLONASS, since the L1 signal's limitations matter less there — reflecting hardware tailored to each product (citing MacRumors).