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rmc.go
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rmc.go
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package nmea
const (
// TypeRMC type for RMC sentences
TypeRMC = "RMC"
// ValidRMC character
ValidRMC = "A"
// InvalidRMC character
InvalidRMC = "V"
)
// RMC is the Recommended Minimum Specific GNSS data.
// http://aprs.gids.nl/nmea/#rmc
// https://gpsd.gitlab.io/gpsd/NMEA.html#_rmc_recommended_minimum_navigation_information
//
// Format: $--RMC,hhmmss.ss,A,ddmm.mm,a,dddmm.mm,a,x.x,x.x,xxxx,x.x,a*hh<CR><LF>
// Format NMEA 2.3: $--RMC,hhmmss.ss,A,ddmm.mm,a,dddmm.mm,a,x.x,x.x,xxxx,x.x,a,m*hh<CR><LF>
// Format NMEA 4.1: $--RMC,hhmmss.ss,A,ddmm.mm,a,dddmm.mm,a,x.x,x.x,xxxx,x.x,a,m,s*hh<CR><LF>
// Example: $GNRMC,220516,A,5133.82,N,00042.24,W,173.8,231.8,130694,004.2,W*6E
// $GNRMC,142754.0,A,4302.539570,N,07920.379823,W,0.0,,070617,0.0,E,A*21
// $GNRMC,102014.00,A,5550.6082,N,03732.2488,E,000.00000,092.9,300518,,,A,V*3B
type RMC struct {
BaseSentence
Time Time // Time Stamp
Validity string // validity - A-ok, V-invalid
Latitude float64 // Latitude
Longitude float64 // Longitude
Speed float64 // Speed in knots
Course float64 // True course
Date Date // Date
Variation float64 // Magnetic variation
FFAMode string // FAA mode indicator (filled in NMEA 2.3 and later)
NavStatus string // Nav Status (NMEA 4.1 and later)
}
// newRMC constructor
func newRMC(s BaseSentence) (RMC, error) {
p := NewParser(s)
p.AssertType(TypeRMC)
m := RMC{
BaseSentence: s,
Time: p.Time(0, "time"),
Validity: p.EnumString(1, "validity", ValidRMC, InvalidRMC),
Latitude: p.LatLong(2, 3, "latitude"),
Longitude: p.LatLong(4, 5, "longitude"),
Speed: p.Float64(6, "speed"),
Course: p.Float64(7, "course"),
Date: p.Date(8, "date"),
Variation: p.Float64(9, "variation"),
}
if p.EnumString(10, "direction", West, East) == West {
m.Variation = 0 - m.Variation
}
if len(p.Fields) > 11 {
m.FFAMode = p.String(11, "FAA mode") // not enum because some devices have proprietary "non-nmea" values
}
if len(p.Fields) > 12 {
m.NavStatus = p.EnumString(
12,
"navigation status",
NavStatusAutonomous,
NavStatusDifferential,
NavStatusEstimated,
NavStatusManualInput,
NavStatusSimulated,
NavStatusDataNotValid,
NavStatusDataValid,
)
}
return m, p.Err()
}