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Mo’Saci Science

Magic and Science in Action

A little magic. A lot of science. And GPS, finally explained.

Mo’ Saci Science is a friendly hub for understanding GPS, GNSS and the technology behind knowing where anything is. Satellites, signals and trackers, made clear.

MoSaciScience is not Mosaic Science. Looking for the magazine? Visit Mosaic Science.

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Who is Saci, and why GPS?

Saci is a one-legged trickster from Brazilian folklore who wears a red magical cap. As people who build with science and technology, we think the best ideas come from keeping that childlike wonder alive. So we put “Mo’ Saci” into science, and pointed all that curiosity at one beautifully practical question: how do we always know where things are?

Read our story →

Start here

Your GPS hub, four doors in

Pick a path. Everything connects.

The 60-second version

Every GPS fix is just three parts working together

🛰️01

Space Segment

A constellation of 30+ satellites circling Earth twice a day, each broadcasting its position and a precise time.

📡02

Control Segment

Ground stations that track every satellite, check its health and keep its clock honest to the nanosecond.

📱03

User Segment

The receiver in your phone, car or tracker that listens to several satellites and works out exactly where it is.

The constellations

Meet the systems behind your blue dot

GPS is one of four global networks circling overhead right now. Most modern receivers listen to all of them at once. Hover a system to follow its satellites.

Fresh from the blog

Field notes worth your time

Stay curious

Got a GPS question we haven’t answered yet?

Send it our way. We turn the best questions into clear, friendly guides.