go-ubx

UBX binary protocol library for u-blox GNSS receivers in Go.

Supported Messages

Message	Class	ID	Direction	Description
NAV-PVT	0x01	0x07	Rx	Position, Velocity, Time
NAV-SAT	0x01	0x35	Rx	Satellite Information (elevation, azimuth, CN0 for skyplot)
NAV-SIG	0x01	0x43	Rx	Signal Information (quality, health, usage flags)
RXM-RAWX	0x02	0x15	Rx	Multi-GNSS Raw Measurements
MON-RF	0x0A	0x38	Rx	RF Information (jamming/spoofing)
RXM-SFRBX	0x02	0x13	Rx	Raw Subframe Data
ACK-ACK	0x05	0x01	Rx	Acknowledgment
ACK-NAK	0x05	0x00	Rx	Negative Acknowledgment
CFG-VALGET	0x06	0x8B	Tx/Rx	Configuration Get (poll + response)
CFG-VALSET	0x06	0x8A	Tx	Configuration Set

Unknown messages are returned as *RawMessage without error.

Decoding

dec := ubx.NewDecoder(serialPort)
for {
    msg, err := dec.Decode()
    if err == io.EOF {
        break
    }
    if err != nil {
        continue
    }

    switch m := msg.(type) {
    case *ubx.NavPVT:
        fmt.Printf("PVT: %.7f, %.7f fix=%d sats=%d\n",
            m.LatDeg(), m.LonDeg(), m.FixType, m.NumSV)
    case *ubx.NavSAT:
        for _, sv := range m.Svs {
            fmt.Printf("SAT: gnss=%d sv=%d elev=%d azim=%d cno=%d used=%v\n",
                sv.GnssID, sv.SvID, sv.Elev, sv.Azim, sv.CNO, sv.SvUsed())
        }
    case *ubx.NavSig:
        for _, s := range m.Signals {
            fmt.Printf("SIG: gnss=%d sv=%d cno=%d quality=%s health=%d\n",
                s.GnssID, s.SvID, s.CNO, s.QualityStr(), s.Health())
        }
    case *ubx.MonRF:
        for _, b := range m.Blocks {
            fmt.Printf("RF: jamming=%s jamInd=%d\n",
                b.JammingState(), b.JamInd)
        }
    case *ubx.RxmRAWX:
        fmt.Printf("RAWX: %d measurements, week=%d\n",
            m.NumMeas, m.Week)
    case *ubx.AckAck:
        fmt.Printf("ACK: %s\n", m.AckedClassID())
    case *ubx.AckNak:
        fmt.Printf("NAK: %s\n", m.NakedClassID())
    case *ubx.CfgValget:
        rate, _ := m.GetU1(ubx.KeyMsgoutNavPvtUSB)
        fmt.Printf("NAV-PVT rate: %d\n", rate)
    }
}

Configuring the Receiver

// Enable messages on USB port
frame := ubx.NewCfgValset(ubx.LayerRAM).
    AddU1(ubx.KeyMsgoutNavPvtUSB, 1).
    AddU1(ubx.KeyMsgoutNavSatUSB, 1).
    AddU1(ubx.KeyMsgoutNavSigUSB, 1).
    AddU1(ubx.KeyMsgoutRxmRawxUSB, 1).
    AddU1(ubx.KeyMsgoutMonRfUSB, 1).
    Build()
serialPort.Write(frame)

// Set measurement rate to 10Hz
serialPort.Write(ubx.SetMeasurementRate(100))

// Read current configuration
serialPort.Write(ubx.PollCfgValget(ubx.PollLayerRAM,
    ubx.KeyMsgoutNavPvtUSB,
    ubx.KeyRateMeas,
))

Custom Parsers

ubx.RegisterParser(0x01, 0x03, func(classID ubx.ClassID, payload []byte) (ubx.Message, error) {
    // decode your custom message
})
defer ubx.UnregisterParser(0x01, 0x03)

Install

go get github.com/keitaj/go-ubx

License

MIT