An open navigation observatory
NavListen is open hardware and software for recording, decoding, and independently checking the satellite signals that tell the world where—and when—it is.
Open source · Apache 2.0 · Built in public
Why this exists
Phones, ships, power grids, data centers, farms, and emergency services all take timing and position from radio signals sent thousands of kilometers through space. Interference is local. Bad ephemerides are global. Either can look ordinary if no one is keeping the original broadcast.
We think navigation deserves a public observatory: independent receivers, transparent math, replayable history, and enough geographic reach to tell a broken satellite from a broken sky over one neighborhood.
Trusting a blue dot is easy.
Proving it is the work.
A complete signal path
Each layer has a narrow job, a documented interface, and an inspectable record.
The observer
Our purpose-built ESP32 observer pairs a u-blox or Septentrio receiver with hardware-backed ECC identity, then forwards the raw navigation messages satellites actually broadcast.
The wire
Tiny C and ESP32 feeders reconnect, retransmit, and preserve provenance. The edge stays simple so every decoder improvement can replay history.
The core
A clean-room Go library decodes public signal specifications, propagates every orbit, and checks clocks, ephemerides, and receiver physics.
The network
Independent stations corroborate the same broadcast from different places. Federation makes a solo receiver part of something much larger.
Open hardware, with a pulse
A fabrication-ready four-layer board built specifically to observe navigation. The receiver listens. The sensors add physical context. The secure element lets every observation keep its identity across the network.
Software that remembers
NavListen stores raw navigation frames beside decoded state. The archive can be replayed when a decoder is corrected or a new signal is added. When two receivers disagree, the original observation is still there.
Go decoders and orbit models authored from public interface specifications.
Orbit, clock, RF, and physical plausibility become typed, replayable events.
A versioned API, event stream, and native Integrity Station clients for the network.
One sky, many witnesses
One station can preserve a broadcast. A fleet can distinguish receiver trouble from local interference. A federation can see regional systems from the places they were built to serve.
There is room at the workbench
This project gets better with more disciplines, more stations, and more points of view. Curiosity is enough to begin; GNSS expertise can come later.
Run a feeder with a supported receiver or help bring up the fabrication-ready observer board. Geographic diversity is the instrument.
I can host an observer ↗Work on GNSS decoders, Go services, embedded C, Swift clients, RF detection, data visualization, or the public API.
I want to build ↗Navigation needs RF engineers, researchers, technical writers, fabricators, operators, and curious people who ask better questions.
I have another idea ↗THE SKY IS ALREADY TALKING
