swift-sgp4

swift-sgp4 is a Swift package for computing satellite positions from two-line elements (TLE).
It wraps the sgp4lib implementation (by Daniel Warner) and brings it into the Swift ecosystem with a clean, modern API.

Why swift-sgp4? Link to heading

Satellites orbiting Earth follow predictable paths, but turning raw orbital data into usable positions isn’t trivial. The SGP4 model (Simplified General Perturbations 4) has long been the standard for propagating satellite orbits from TLE data.

With swift-sgp4, this capability is now directly available to Swift developers — whether you’re building an iOS app for satellite tracking, a macOS tool for research, or experimenting with orbital mechanics in Swift Playgrounds.

The approach Link to heading

  • Native Swift package: integrates seamlessly with Swift Package Manager
  • Trusted foundation: built on the sgp4lib implementation
  • Practical API: work with TLEs and get back latitude, longitude, altitude, and velocity data

It’s designed to make orbital prediction accessible without sacrificing accuracy.

Philosophy Link to heading

swift-sgp4 is about bridging worlds: the rigor of orbital mechanics with the elegance of Swift.
It doesn’t try to reinvent the SGP4 model — instead, it focuses on making it approachable, reliable, and ready to use in modern Swift projects.

Learn more Link to heading

  • 📖 Full documentation and usage examples are on GitHub
  • 📦 Install via Swift Package Manager