1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
|
package nmea
const (
// TypeVTG type for VTG sentences
TypeVTG = "VTG"
)
// VTG represents track & speed data.
// http://aprs.gids.nl/nmea/#vtg
// https://gpsd.gitlab.io/gpsd/NMEA.html#_vtg_track_made_good_and_ground_speed
//
// Format: $--VTG,x.x,T,x.x,M,x.x,N,x.x,K*hh<CR><LF>
// Format (NMEA 2.3+): $--VTG,x.x,T,x.x,M,x.x,N,x.x,K,m*hh<CR><LF>
// Example: $GPVTG,45.5,T,67.5,M,30.45,N,56.40,K*4B
// $GPVTG,220.86,T,,M,2.550,N,4.724,K,A*34
type VTG struct {
BaseSentence
TrueTrack float64
MagneticTrack float64
GroundSpeedKnots float64
GroundSpeedKPH float64
FFAMode string // FAA mode indicator (filled in NMEA 2.3 and later)
}
// newVTG parses the VTG sentence into this struct.
// e.g: $GPVTG,360.0,T,348.7,M,000.0,N,000.0,K*43
func newVTG(s BaseSentence) (Sentence, error) {
p := NewParser(s)
p.AssertType(TypeVTG)
vtg := VTG{
BaseSentence: s,
TrueTrack: p.Float64(0, "true track"),
MagneticTrack: p.Float64(2, "magnetic track"),
GroundSpeedKnots: p.Float64(4, "ground speed (knots)"),
GroundSpeedKPH: p.Float64(6, "ground speed (km/h)"),
}
if len(p.Fields) > 8 {
vtg.FFAMode = p.String(8, "FAA mode") // not enum because some devices have proprietary "non-nmea" values
}
return vtg, p.Err()
}
|
