Satellite Positioning: How GPS, GNSS, and Formation Flying Keep Spacecraft Accurate

When you think of satellite positioning, the process of determining a satellite’s exact location in orbit using signals from ground stations and other satellites. Also known as orbital tracking, it’s what keeps the International Space Station from drifting into the wrong path and lets your phone know exactly where you are. It’s not magic—it’s math, radio signals, and incredibly precise clocks working together.

Satellite positioning isn’t just about GPS. It includes GNSS, global navigation satellite systems like Europe’s Galileo, Russia’s GLONASS, and China’s BeiDou, which work alongside the U.S. GPS network to give you better accuracy, especially in cities or mountains. Modern receivers use signals from multiple systems at once, cutting errors down to just a few centimeters. That’s the same tech used in precision farming to guide tractors and in space missions to keep satellites flying in perfect formation. Speaking of which, formation flying satellites, multiple satellites that move in coordinated patterns to act like one giant instrument—like the ones NASA uses to study Earth’s gravity or map distant stars—depend entirely on real-time positioning data. If one satellite drifts by even a meter, the whole mission fails.

Behind every accurate position is a network of ground antennas, atomic clocks, and algorithms that correct for atmospheric delays, relativity effects, and even tiny gravitational tugs from the Moon. The system has to update thousands of times per second. That’s why companies like SpaceX and Rocket Lab track their rockets down to the millimeter during launch. And when satellites need to avoid collisions—like with the growing cloud of space junk—positioning data tells them exactly when and where to move. It’s not just about knowing where you are. It’s about knowing where everything else is, too.

From the ISS using GPS to stay aligned with Earth, to satellites in low Earth orbit syncing up for internet coverage, to deep-space probes navigating by star positions and Earth-based signals—satellite positioning is the invisible backbone of modern space operations. You won’t see it, but if it fails, your navigation app glitches, your weather forecast goes wrong, and satellites could crash. The posts below dive into how this works in practice: from the sensors that track satellites in real time, to how new missions use relative navigation to fly in tight clusters, to why military and civilian signals are now just as accurate—and why that matters for the future of space.