📍 Space Glossary

Navigation & Timing

How satellites provide global positioning, navigation, and timing services — from atomic clocks and signal processing to the constellations that underpin GPS, Galileo, GLONASS, and BeiDou. 8 terms, each explained in plain language with key data and links to live trackers.

AC Atomic Clock Ultra-precise clock enabling satellite navigation ≈ 30 cm position error+38 µs/day, corrected B BeiDou China's independent global navigation system June 2020~21,500 km · 55° DOP DOP How satellite geometry affects positioning accuracy <22–5 GNSS Umbrella term for all satellite navigation systems 236 liveMEO, ~19,100–23,200 km GPS GPS US satellite navigation system — 31 satellites in MEO 20,200 km (MEO)US Space Force GS GPS Spoofing Transmitting fake GPS signals to deceive a receiver about its position Navigation & Timing PNT PNT The three services satellite navigation provides Where you areHow to get there P Pseudorange Approximate satellite-to-receiver distance from signal timing Navigation & Timing

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