For research
Study orbits and clocks.
Explore how satellite orbits and clocks change, with original messages to revisit.
Ground Monitoring for Space Integrity
Satellites broadcast.
We listen.
NavListen records satellite navigation messages so we can study orbits, clocks, and signals. Host an observer, explore the data, or help build the tools.
Open hardware. Open software. Everyone’s welcome.
A SHARED SKYILLUSTRATION
OBSERVER ON EARTH
GPS
Galileo
BeiDou
QZSS
Satellite navigation.Beyond the blue dot.
One observatory.
A whole sky to explore.
- GGPS
- SSBAS
- EGalileo
- CBeiDou
- JQZSS
- RGLONASS
Why listen
Track satellite orbits and clocks.
Navigation satellites broadcast the orbit and clock data receivers use to calculate position and time. They also send information about satellite health and available signals.
NavListen archives these messages and compares observations from different stations. Researchers and builders can return to the original data to investigate changes and develop their own tools.
For operations
Compare receiver observations.
Study observations from your receiver alongside data from other stations.
For builders
Build with open tools.
Use the hardware, software, and API to create tools and experiments.
How it works
From antenna to evidence.
Receive, archive, decode, and compare satellite messages.
Receive
Receive satellite messages
Bring a patch of sky into focus. Our purpose-built ESP32-S3 observer combines a satellite receiver, Wi-Fi, and station sensors on one board.
- u-blox + Septentrio
- Open hardware
Record
Archive each message
Feeder software sends the messages to a collector. The archive keeps each original message with the identity of the station that received it.
- Raw message archive
- Station identity
Understand
Decode orbits and clocks
Decoders turn supported broadcasts into satellite orbits, clock corrections, and health information. The calculations follow published signal specifications.
- Orbit and clock models
- Documented calculations
Explore
Compare observations
Compare observations across stations and over time. Use the API and Integrity Station app to explore the data, investigate changes, and build your own tools.
- Data API
- Integrity Station app
A small board. A whole sky.
Meet the observer.
Put your corner of the sky to work. The observer sends satellite messages and local conditions to NavListen over Wi-Fi. Its constellation lights bring reception to your desk, with brightness you can adjust at a touch.
Ask about the observer- Receiver
- u-blox receiver options
Navigation messages straight from the satellites - Feeder
- ESP32-S3
Wi-Fi connected. USB-C powered. - Identity
- Hardware-backed station identity
A secure element keeps the station’s key on the board - Sensors
- Pressure · temperature · humidity
See what’s happening around your receiver
Receiver options
Three boards. One observer.
Each board is sized for a different receiver module. Explore the components in these 3D renders, shown with a classic green PCB finish.
Integrity Station companion app
Your station. Wherever you are.
From the first connection to your next discovery, keep your observer close.
Make the connection
Start with a scan.
Scan your observer’s setup label with your iPhone or iPad. Bluetooth setup brings your Wi-Fi and station details across. Your patch of sky joins the picture.
Stay in touch
Know how it’s doing.
Check reception, local conditions, and station health from your iPhone, iPad, or Mac. Private diagnostics help you spot interruptions and understand what changed.
Keep discovering
Let your observer grow.
Bring improvements to your observer with signed firmware updates over Wi-Fi. Choose when to update and check its firmware version in the app.
From spaceA navigation message
On the groundA receiving station
One message, a lasting recordWhat we keep, and why it matters
- Original broadcast
- The message as received, ready to decode again.
- Time & source
- When it arrived and which station heard it.
- Decoded information
- Orbit, clock, and health data from supported signals.
A record you can return to as the tools improve.
A reusable message archive
Revisit every recorded message.
NavListen keeps original navigation messages alongside their decoded information. As decoders improve or new questions arise, you can run the calculations again using the same recorded data.
- 01Follow the calculations
Explore decoders and orbit models written from published satellite specifications.
- 02Put changes in context
Review orbit, clock, and receiver observations alongside recorded events.
- 03Work with the data
Use the API, event stream, and Integrity Station app in your own investigations.
Expand the network
Help us observe more satellites.
Stations in different locations receive signals from different satellites. Their observations help us compare local conditions and study regional navigation systems. Host an observer at home, on campus, or at work to contribute data from your location.
Explore hosting a stationA NETWORK WE CAN BUILD TOGETHER
A HOME
A CAMPUS
A WORKPLACE
A RESEARCH SITE
YOUR STATION
Host, build, or contribute
Come help us listen.
This project gets better with more disciplines, more stations, and more points of view. You’re welcome whether satellite navigation is your day job or a new curiosity.
Host an observer
Have room for an antenna and an internet connection? Start with our observer or a supported receiver. Tell us where you’d like to listen and we’ll help you find a setup.
Talk about hostingMake something with us
Help with hardware, software, testing, documentation, or design. Bring a skill you enjoy using, or something you’d like to learn.
Find a way to contributeBring your perspective
A research question, a classroom project, a useful connection, or an idea we haven’t thought of. We’d like to hear what brought you here.
Share an ideaFor teams & organizations
Tell us what you want to achieve.
Understand observations at your site, answer a research question, or put navigation data to use in your own tools. Let’s talk about the results you need and how NavListen can help.
Discuss your goals
A conversation is a good place to start.
Getting started
Plan your contribution.
Find out what you need to host an observer, use your receiver, or contribute without hardware.
What do I need to host an observer?
Give your observer a suitable antenna with a clear view of the sky, USB-C power, and Wi-Fi. Scan its setup label with Integrity Station on your iPhone or iPad to connect over Bluetooth and add your network and station details. Browser setup is available too. We’ll help you choose the right antenna and find a good spot.
Can I take part without hardware?
Absolutely. Software, documentation, design, testing, and research all help the project grow. Tell us what interests you and we’ll find a useful place to begin.
Can my team use NavListen?
We welcome conversations about research deployments, site monitoring, and integration into your own tools. Share your goals, location, and timeline so we can discuss the hardware, data access, and support that fit your project.
Can I use a receiver I already have?
The stack works with u-blox and Septentrio receiver data. The messages available depend on the model and firmware: u-blox navigation messages are decoded centrally, while Septentrio data is currently captured for the archive. Send us your receiver model and we’ll help check what it can contribute.