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gnss-sdr

A complete GPS and GNSS receiver built entirely in software

What it does

Takes raw RF samples from an SDR and does everything a GPS chip does: acquisition, tracking, demodulating the navigation message, and computing a position fix. It handles GPS, Galileo, GLONASS and BeiDou, and it can work from a live SDR or from a recorded file.

Why you would want it

A GPS receiver is normally a sealed box that emits a position, and there is no way to see inside it. This opens the box: every stage is visible and configurable, the intermediate products can be logged, and a recorded capture can be reprocessed with different settings. For understanding how satellite navigation actually works, or for research into interference and spoofing detection, nothing else is close.

Before it will work

An SDR with enough bandwidth -- roughly 2 MHz minimum for GPS L1 -- and an active GNSS antenna, which needs bias tee power the dongle may not provide. Substantial CPU: real-time multi-constellation processing is genuinely demanding, and file-based post-processing is the usual route.

How it installs

  • apt: gnss-sdr

Known problems

Configuration is a long file with many interacting parameters, and a receiver that never acquires gives no clue which one is wrong -- start from a shipped example and a known-good recording rather than from your own antenna. Antenna and bias tee are where most first attempts fail: GNSS signals are below the noise floor and a passive antenna will not do.

Keeping it current

  • probe: apt policy
  • strategy: apt_upgrade

Where to get help with the software itself

The GNSS-SDR project at CTTC. Documentation on the site is thorough and the mailing list is active.

Source: catalog/packages/gnss-sdr.yaml