GPSD OSM Viewer

Minimal Android/Kotlin app that connects to a remote gpsd server over TCP/IP, reads JSON TPV position reports, and displays the fix on an OpenStreetMap map using osmdroid.

What it does

• Connects to gpsd via IP/host and TCP port, default 2947.
• Sends:

?WATCH={"enable":true,"json":true};

• Parses TPV JSON reports.
• Uses lat/lon when mode >= 2.
• Shows position as a marker on an osmdroid/OpenStreetMap map.
• Displays basic speed/track/error fields when present.

Server-side gpsd notes

On the machine/router/Raspberry Pi where the GNSS receiver is attached, gpsd must be reachable from the Android device. On many Linux setups gpsd only listens locally unless explicitly configured for remote clients.

Typical quick test on the gpsd host:

gpspipe -w -n 10

Typical manual gpsd test mode, adjust device path:

sudo systemctl stop gpsd gpsd.socket
sudo gpsd -N -G -D 3 /dev/ttyUSB0

Then from another machine:

nc <gpsd-host-ip> 2947
?WATCH={"enable":true,"json":true};

You should see JSON objects including TPV.

Android build

Open this folder in Android Studio and run the app configuration.

The project uses:

• Android Gradle Plugin 9.2.1
• Built-in Kotlin support from AGP 9.x
• osmdroid 6.1.20
• kotlinx-coroutines-android 1.10.2

If your Android Studio is older, reduce the Android Gradle Plugin version in build.gradle.kts or create a fresh Android Studio project and copy MainActivity.kt plus the dependencies.

OpenStreetMap tile usage

This prototype uses the public OSM tile layer through osmdroid. For long-term/public use, do not bulk-download or pre-seed tiles. Use a proper tile provider, your own tile server, or an offline vector-map solution if the app is used heavily or offline.

Security note

The gpsd TCP protocol is plain text. Do not expose gpsd directly to the public Internet. Use LAN/VPN/SSH tunnel or a small authenticated gateway if the receiver is remote.