Asv.Gnss is a .NET library for parsing GNSS, aviation, and receiver-control protocols. The project is distributed as the Asv.Gnss NuGet package and also includes console tools for RTCM v3 and ASTERIX stream diagnostics.

• Parse and serialize NMEA 0183 messages: GBS, GGA, GLL, GSA, GST, GSV, RMC, VTG, ZDA.
• Parse RTCM v2 and RTCM v3, including legacy messages, ephemeris, stationary RTK, GLONASS bias, and MSM3/MSM4/MSM5/MSM7 messages.
• Support u-blox UBX messages: ACK, CFG, INF, MON, NAV, RXM.
• Parse ASTERIX categories 001, 002, 004, 010, 020, 021, 034, 048, and 247.
• Additional protocols and parsers: ADS-B, ASV, Raw GPS, Raw GLONASS, SBF, ComNav, and Javad.
• Integration with Asv.IO: protocol registration, routers, ports, GNSS device discovery, and NMEA/RTCM/UBX microservices.

• .NET SDK 10.0.
• Windows, Linux, or macOS for the library. The local publishing batch scripts require Windows.
• Visual Studio, JetBrains Rider, or another IDE with SDK-style .NET project support.

Check the installed SDK version:

dotnet --version

Using the .NET CLI:

dotnet add package Asv.Gnss

Using NuGet Package Manager:

Install-Package Asv.Gnss

The example below creates an Asv.IO protocol, registers GNSS protocols, and opens a port:

using Asv.Gnss;
using Asv.IO;
using R3;

var protocol = Protocol.Create(builder =>
{
    builder.Protocols.RegisterNmeaProtocol();
    builder.Protocols.RegisterRtcmV2Protocol();
    builder.Protocols.RegisterRtcmV3Protocol();
    builder.Protocols.RegisterUbxProtocol();
    builder.Protocols.RegisterAsterixProtocol();
    builder.Features.RegisterBroadcastAllFeature();
    builder.Features.RegisterEndpointIdTagFeature();
});

var router = protocol.CreateRouter("GNSS");
router.AddPort("serial:COM4?br=115200&enabled=true");

using var subscription = router.OnRxMessage.Subscribe(packet =>
{
    Console.WriteLine(packet);
});

Connection string examples supported by the Asv.IO transport layer:

tcp://127.0.0.1:9002
tcps://127.0.0.1:9002
udp://127.0.0.1:1234?rhost=127.0.0.1&rport=1235
serial:COM4?br=115200
serial:/dev/ttyACM0?br=115200

TCP uses separate schemes for client and server ports:

• tcp://host:port creates a TCP client port that connects to a remote endpoint.
• tcps://host:port creates a TCP server port that listens for incoming clients.

Register the GNSS device factory:

var explorer = DeviceExplorer.Create(router, builder =>
{
    builder.Factories.RegisterGnssDevice();
});

The UBX microservice provides helper methods for u-blox devices:

await ubx.GetMonVer(cancel);
await ubx.GetNavPvt(cancel);
await ubx.SetSurveyInMode(minDuration: 60, positionAccuracyLimit: 2, cancel: cancel);
await ubx.SetupRtcmMSM4Rate(msgRate: 1, cancel: cancel);
await ubx.TurnOffNmea(cancel);
await ubx.RebootReceiver(cancel);

The Asv.Gnss.Shell project contains diagnostic commands.

Read an RTCM v3 stream:

dotnet run --project src/Asv.Gnss.Shell -- rtcm --cs "tcp://172.16.0.1:30"

Use tcps://0.0.0.0:7341 when the shell should listen for incoming TCP clients instead of connecting as a TCP client.

Parse an ASTERIX stream file:

dotnet run --project src/Asv.Gnss.Shell -- asterix-stream --file "path/to/input.stream"

Export CAT021 tracks from an ASTERIX stream to KML:

dotnet run --project src/Asv.Gnss.Shell -- asterix-stream --file "path/to/input.stream" --kml "tracks.kml" --min-track-points 2

The nmea command exists in the codebase, but it is currently not registered in Program.cs.

Restore dependencies:

dotnet restore src/Asv.Gnss.sln

Build the solution:

dotnet build src/Asv.Gnss.sln

Run tests:

dotnet test src/Asv.Gnss.sln

Build the library NuGet package:

dotnet pack src/Asv.Gnss/Asv.Gnss.csproj -c Release

On Windows, you can use the root build script:

build.bat

The script reads the version from git describe --tags, applies it with dotnet-setversion, builds the projects, and runs dotnet pack.

asv-gnss/
  README.md
  LICENSE
  build.bat
  publish_nuget.bat
  src/
    Asv.Gnss.sln
    Directory.Build.props
    Asv.Gnss/
      Devices/
      Microservices/
      Parsers/
      Protocols/
    Asv.Gnss.Shell/
    Asv.Gnss.Test/

Main projects:

• Asv.Gnss - protocol, message, parser, GNSS device factory, and microservice library.
• Asv.Gnss.Shell - console commands for working with data streams and ASTERIX stream files.
• Asv.Gnss.Test - xUnit v3 protocol tests and binary RTCM/ASTERIX test resources.

Product version, target framework, and shared dependency versions are defined in src/Directory.Build.props.

The publish_nuget.bat script publishes the Asv.Gnss package to NuGet.org and GitHub Packages:

publish_nuget.bat

Before publishing, build a Release package whose version matches git describe --tags.

This project is licensed under the MIT License. See LICENSE.

• Repository: https://github.com/asv-soft/asv-gnss
• Issues: https://github.com/asv-soft/asv-gnss/issues
• ASV documentation: https://docs.asv.me/
• Telegram: https://t.me/asvsoft