stratux/main/ry835ai.go

1194 wiersze
35 KiB
Go

/*
Copyright (c) 2015-2016 Christopher Young
Distributable under the terms of The "BSD New"" License
that can be found in the LICENSE file, herein included
as part of this header.
ry835ai.go: GPS functions, GPS init, AHRS status messages, other external sensor monitoring.
*/
package main
import (
"fmt"
"log"
"strconv"
"strings"
"sync"
"time"
"bufio"
"github.com/kidoman/embd"
_ "github.com/kidoman/embd/host/all"
"github.com/kidoman/embd/sensor/bmp180"
"github.com/tarm/serial"
"os"
"os/exec"
"../mpu6050"
)
type SituationData struct {
mu_GPS *sync.Mutex
// From GPS.
lastFixSinceMidnightUTC uint32
Lat float32
Lng float32
quality uint8
GeoidSep float32 // geoid separation, ft, MSL minus HAE (used in altitude calculation)
Satellites uint16 // satellites used in solution
SatellitesTracked uint16 // satellites tracked (almanac data received)
SatellitesSeen uint16 // satellites seen (signal received)
Accuracy float32 // 95% confidence for horizontal position, meters.
NACp uint8 // NACp categories are defined in AC 20-165A
Alt float32 // Feet MSL
AccuracyVert float32 // 95% confidence for vertical position, meters
GPSVertVel float32 // GPS vertical velocity, feet per second
LastFixLocalTime time.Time
TrueCourse uint16
GroundSpeed uint16
LastGroundTrackTime time.Time
LastNMEAMessage time.Time // time valid NMEA message last seen
mu_Attitude *sync.Mutex
// From BMP180 pressure sensor.
Temp float64
Pressure_alt float64
lastTempPressTime time.Time
// From MPU6050 accel/gyro.
Pitch float64
Roll float64
Gyro_heading float64
LastAttitudeTime time.Time
}
var serialConfig *serial.Config
var serialPort *serial.Port
var readyToInitGPS bool // TO-DO: replace with channel control to terminate goroutine when complete
/*
file:///Users/c/Downloads/u-blox5_Referenzmanual.pdf
Platform settings
Airborne <2g Recommended for typical airborne environment. No 2D position fixes supported.
p.91 - CFG-MSG
Navigation/Measurement Rate Settings
Header 0xB5 0x62
ID 0x06 0x08
0x0064 (100 ms)
0x0001
0x0001 (GPS time)
{0xB5, 0x62, 0x06, 0x08, 0x00, 0x64, 0x00, 0x01, 0x00, 0x01}
p.109 CFG-NAV5 (0x06 0x24)
Poll Navigation Engine Settings
*/
func chksumUBX(msg []byte) []byte {
ret := make([]byte, 2)
for i := 0; i < len(msg); i++ {
ret[0] = ret[0] + msg[i]
ret[1] = ret[1] + ret[0]
}
return ret
}
// p.62
func makeUBXCFG(class, id byte, msglen uint16, msg []byte) []byte {
ret := make([]byte, 6)
ret[0] = 0xB5
ret[1] = 0x62
ret[2] = class
ret[3] = id
ret[4] = byte(msglen & 0xFF)
ret[5] = byte((msglen >> 8) & 0xFF)
ret = append(ret, msg...)
chk := chksumUBX(ret[2:])
ret = append(ret, chk[0])
ret = append(ret, chk[1])
return ret
}
func makeNMEACmd(cmd string) []byte {
chk_sum := byte(0)
for i := range cmd {
chk_sum = chk_sum ^ byte(cmd[i])
}
return []byte(fmt.Sprintf("$%s*%02x\x0d\x0a", cmd, chk_sum))
}
func initGPSSerial() bool {
var device string
baudrate := int(9600)
isSirfIV := bool(false)
log.Printf("Configuring GPS\n")
if _, err := os.Stat("/dev/ttyUSB0"); err == nil {
isSirfIV = true
baudrate = 4800
device = "/dev/ttyUSB0"
} else if _, err := os.Stat("/dev/ttyACM0"); err == nil {
device = "/dev/ttyACM0"
} else if _, err := os.Stat("/dev/ttyAMA0"); err == nil {
device = "/dev/ttyAMA0"
} else {
log.Printf("No suitable device found.\n")
return false
}
log.Printf("Using %s for GPS\n", device)
/* Developer option -- uncomment to allow "hot" configuration of GPS (assuming 38.4 kpbs on warm start)
serialConfig = &serial.Config{Name: device, Baud: 38400}
p, err := serial.OpenPort(serialConfig)
if err != nil {
log.Printf("serial port err: %s\n", err.Error())
return false
} else { // reset port to 9600 baud for configuration
cfg1 := make([]byte, 20)
cfg1[0] = 0x01 // portID.
cfg1[1] = 0x00 // res0.
cfg1[2] = 0x00 // res1.
cfg1[3] = 0x00 // res1.
// [ 7 ] [ 6 ] [ 5 ] [ 4 ]
// 0000 0000 0000 0000 1000 0000 1100 0000
// UART mode. 0 stop bits, no parity, 8 data bits. Little endian order.
cfg1[4] = 0xC0
cfg1[5] = 0x08
cfg1[6] = 0x00
cfg1[7] = 0x00
// Baud rate. Little endian order.
bdrt1 := uint32(9600)
cfg1[11] = byte((bdrt1 >> 24) & 0xFF)
cfg1[10] = byte((bdrt1 >> 16) & 0xFF)
cfg1[9] = byte((bdrt1 >> 8) & 0xFF)
cfg1[8] = byte(bdrt1 & 0xFF)
// inProtoMask. NMEA and UBX. Little endian.
cfg1[12] = 0x03
cfg1[13] = 0x00
// outProtoMask. NMEA. Little endian.
cfg1[14] = 0x02
cfg1[15] = 0x00
cfg1[16] = 0x00 // flags.
cfg1[17] = 0x00 // flags.
cfg1[18] = 0x00 //pad.
cfg1[19] = 0x00 //pad.
p.Write(makeUBXCFG(0x06, 0x00, 20, cfg1))
p.Close()
}
-- End developer option */
// Open port at default baud for config.
serialConfig = &serial.Config{Name: device, Baud: baudrate}
p, err := serial.OpenPort(serialConfig)
if err != nil {
log.Printf("serial port err: %s\n", err.Error())
return false
}
if isSirfIV {
log.Printf("Using SiRFIV config.\n")
// Enable 38400 baud.
p.Write(makeNMEACmd("PSRF100,1,38400,8,1,0"))
baudrate = 38400
p.Close()
time.Sleep(250 * time.Millisecond)
// Re-open port at newly configured baud so we can configure 5Hz messages.
serialConfig = &serial.Config{Name: device, Baud: baudrate}
p, err = serial.OpenPort(serialConfig)
// Enable 5Hz. (To switch back to 1Hz: $PSRF103,00,7,00,0*22)
p.Write(makeNMEACmd("PSRF103,00,6,00,0"))
// Enable GGA.
p.Write(makeNMEACmd("PSRF103,00,00,01,01"))
// Enable GSA.
p.Write(makeNMEACmd("PSRF103,02,00,01,01"))
// Enable RMC.
p.Write(makeNMEACmd("PSRF103,04,00,01,01"))
// Enable VTG.
p.Write(makeNMEACmd("PSRF103,05,00,01,01"))
// Disable GSV.
p.Write(makeNMEACmd("PSRF103,03,00,00,01"))
} else {
// Set 10Hz update. Little endian order.
p.Write(makeUBXCFG(0x06, 0x08, 6, []byte{0x64, 0x00, 0x01, 0x00, 0x01, 0x00}))
// Set navigation settings.
nav := make([]byte, 36)
nav[0] = 0x05 // Set dyn and fixMode only.
nav[1] = 0x00
// dyn.
nav[2] = 0x07 // "Airborne with >2g Acceleration".
nav[3] = 0x02 // 3D only.
p.Write(makeUBXCFG(0x06, 0x24, 36, nav))
// GNSS configuration CFG-GNSS for ublox 7 higher, p. 125 (v8)
//
// NOTE: Max position rate = 5 Hz if GPS+GLONASS used.
// Disable GLONASS to enable 10 Hz solution rate. GLONASS is not used
// for SBAS (WAAS), so little real-world impact.
cfgGnss := []byte{0x00, 0x20, 0x20, 0x05}
gps := []byte{0x00, 0x08, 0x10, 0x00, 0x01, 0x00, 0x01, 0x01}
sbas := []byte{0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x01, 0x01}
beidou := []byte{0x03, 0x00, 0x10, 0x00, 0x00, 0x00, 0x01, 0x01}
qzss := []byte{0x05, 0x00, 0x03, 0x00, 0x00, 0x00, 0x01, 0x01}
glonass := []byte{0x06, 0x04, 0x0E, 0x00, 0x00, 0x00, 0x01, 0x01}
cfgGnss = append(cfgGnss, gps...)
cfgGnss = append(cfgGnss, sbas...)
cfgGnss = append(cfgGnss, beidou...)
cfgGnss = append(cfgGnss, qzss...)
cfgGnss = append(cfgGnss, glonass...)
p.Write(makeUBXCFG(0x06, 0x3E, uint16(len(cfgGnss)), cfgGnss))
// SBAS configuration for ublox 6 and higher
p.Write(makeUBXCFG(0x06, 0x16, 8, []byte{0x01, 0x07, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00}))
// Message output configuration -- disable standard NMEA messages except 1Hz GGA
// Msg DDC UART1 UART2 USB I2C Res
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x00, 0x00, 0x0A, 0x00, 0x0A, 0x00, 0x01})) // GGA
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01})) // GLL
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01})) // GSA
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01})) // GSV
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01})) // RMC
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x05, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01})) // VGT
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})) // GRS
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})) // GST
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})) // ZDA
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})) // GBS
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x0A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})) // DTM
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x0D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})) // GNS
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x0E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})) // ???
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF0, 0x0F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00})) // VLW
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF1, 0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00})) // Ublox,0
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF1, 0x03, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x00})) // Ublox,3
p.Write(makeUBXCFG(0x06, 0x01, 8, []byte{0xF1, 0x04, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x00})) // Ublox,4
// Reconfigure serial port.
cfg := make([]byte, 20)
cfg[0] = 0x01 // portID.
cfg[1] = 0x00 // res0.
cfg[2] = 0x00 // res1.
cfg[3] = 0x00 // res1.
// [ 7 ] [ 6 ] [ 5 ] [ 4 ]
// 0000 0000 0000 0000 0000 10x0 1100 0000
// UART mode. 0 stop bits, no parity, 8 data bits. Little endian order.
cfg[4] = 0xC0
cfg[5] = 0x08
cfg[6] = 0x00
cfg[7] = 0x00
// Baud rate. Little endian order.
bdrt := uint32(38400)
cfg[11] = byte((bdrt >> 24) & 0xFF)
cfg[10] = byte((bdrt >> 16) & 0xFF)
cfg[9] = byte((bdrt >> 8) & 0xFF)
cfg[8] = byte(bdrt & 0xFF)
// inProtoMask. NMEA and UBX. Little endian.
cfg[12] = 0x03
cfg[13] = 0x00
// outProtoMask. NMEA. Little endian.
cfg[14] = 0x02
cfg[15] = 0x00
cfg[16] = 0x00 // flags.
cfg[17] = 0x00 // flags.
cfg[18] = 0x00 //pad.
cfg[19] = 0x00 //pad.
p.Write(makeUBXCFG(0x06, 0x00, 20, cfg))
// time.Sleep(100* time.Millisecond) // pause and wait for the GPS to finish configuring itself before closing / reopening the port
baudrate = 38400
}
p.Close()
time.Sleep(250 * time.Millisecond)
// Re-open port at newly configured baud so we can read messages. ReadTimeout is set to keep from blocking the gpsSerialReader() on misconfigures or ttyAMA disconnects
serialConfig = &serial.Config{Name: device, Baud: baudrate, ReadTimeout: time.Millisecond * 2500}
p, err = serial.OpenPort(serialConfig)
if err != nil {
log.Printf("serial port err: %s\n", err.Error())
return false
}
serialPort = p
log.Printf("GPS configuration complete\n")
return true
}
// func validateNMEAChecksum determines if a string is a properly formatted NMEA sentence with a valid checksum.
//
// If the input string is valid, output is the input stripped of the "$" token and checksum, along with a boolean 'true'
// If the input string is the incorrect format, the checksum is missing/invalid, or checksum calculation fails, an error string and
// boolean 'false' are returned
//
// Checksum is calculated as XOR of all bytes between "$" and "*"
func validateNMEAChecksum(s string) (string, bool) {
//validate format. NMEA sentences start with "$" and end in "*xx" where xx is the XOR value of all bytes between
if !(strings.HasPrefix(s, "$") && strings.Contains(s, "*")) {
return "Invalid NMEA message", false
}
// strip leading "$" and split at "*"
s_split := strings.Split(strings.TrimPrefix(s, "$"), "*")
s_out := s_split[0]
s_cs := s_split[1]
if len(s_cs) < 2 {
return "Missing checksum. Fewer than two bytes after asterisk", false
}
cs, err := strconv.ParseUint(s_cs[:2], 16, 8)
if err != nil {
return "Invalid checksum", false
}
cs_calc := byte(0)
for i := range s_out {
cs_calc = cs_calc ^ byte(s_out[i])
}
if cs_calc != byte(cs) {
return fmt.Sprintf("Checksum failed. Calculated %#X; expected %#X", cs_calc, cs), false
}
return s_out, true
}
// Only count this heading if a "sustained" >7 kts is obtained. This filters out a lot of heading
// changes while on the ground and "movement" is really only changes in GPS fix as it settles down.
//TODO: Some more robust checking above current and last speed.
//TODO: Dynamic adjust for gain based on groundspeed
func setTrueCourse(groundSpeed, trueCourse uint16) {
if myMPU6050 != nil && globalStatus.RY835AI_connected && globalSettings.AHRS_Enabled {
if mySituation.GroundSpeed >= 7 && groundSpeed >= 7 {
myMPU6050.ResetHeading(float64(trueCourse), 0.10)
}
}
}
func calculateNACp(accuracy float32) uint8 {
ret := uint8(0)
if accuracy < 3 {
ret = 11
} else if accuracy < 10 {
ret = 10
} else if accuracy < 30 {
ret = 9
} else if accuracy < 92.6 {
ret = 8
} else if accuracy < 185.2 {
ret = 7
} else if accuracy < 555.6 {
ret = 6
}
return ret
}
/*
processNMEALine parses NMEA-0183 formatted strings against several message types.
Standard messages supported: RMC GGA VTG GSA
U-blox proprietary messages: PUBX,00 PUBX,03 PUBX,04
return is false if errors occur during parse, or if GPS position is invalid
return is true if parse occurs correctly and position is valid.
*/
func processNMEALine(l string) bool {
replayLog(l, MSGCLASS_GPS)
l_valid, validNMEAcs := validateNMEAChecksum(l)
if !validNMEAcs {
log.Printf("GPS error. Invalid NMEA string: %s\n", l_valid) // remove log message once validation complete
return false
}
x := strings.Split(l_valid, ",")
mySituation.LastNMEAMessage = stratuxClock.Time
if x[0] == "PUBX" { // UBX proprietary message
if x[1] == "00" { // position message
if len(x) < 20 {
return false
}
mySituation.mu_GPS.Lock()
defer mySituation.mu_GPS.Unlock()
// Do the accuracy / quality fields first to prevent invalid position etc. from being sent downstream
// field 8 = nav status
// DR = dead reckoning, G2= 2D GPS, G3 = 3D GPS, D2= 2D diff, D3 = 3D diff, RK = GPS+DR, TT = time only
okReturn := true
if x[8] == "D2" || x[8] == "D3" {
mySituation.quality = 2
} else if x[8] == "G2" || x[8] == "G3" {
mySituation.quality = 1
} else if x[8] == "DR" || x[8] == "RK" {
mySituation.quality = 6
} else if x[8] == "NF" {
mySituation.quality = 0
okReturn = false // better to have no data than wrong data
} else {
mySituation.quality = 0
okReturn = false // better to have no data than wrong data
}
// field 9 = horizontal accuracy, m
hAcc, err := strconv.ParseFloat(x[9], 32)
if err != nil {
okReturn = false
}
mySituation.Accuracy = float32(hAcc * 2) // UBX reports 1-sigma variation; NACp is 95% confidence (2-sigma)
// NACp estimate.
mySituation.NACp = calculateNACp(mySituation.Accuracy)
// field 10 = vertical accuracy, m
vAcc, err := strconv.ParseFloat(x[10], 32)
if err != nil {
okReturn = false
}
mySituation.AccuracyVert = float32(vAcc * 2) // UBX reports 1-sigma variation; we want 95% confidence
if !okReturn {
return false
}
// field 2 = time
if len(x[2]) < 9 {
return false
}
hr, err1 := strconv.Atoi(x[2][0:2])
min, err2 := strconv.Atoi(x[2][2:4])
sec, err3 := strconv.Atoi(x[2][4:6])
if err1 != nil || err2 != nil || err3 != nil {
return false
}
mySituation.lastFixSinceMidnightUTC = uint32((hr * 60 * 60) + (min * 60) + sec)
// field 3-4 = lat
if len(x[3]) < 10 {
return false
}
hr, err1 = strconv.Atoi(x[3][0:2])
minf, err2 := strconv.ParseFloat(x[3][2:10], 32)
if err1 != nil || err2 != nil {
return false
}
mySituation.Lat = float32(hr) + float32(minf/60.0)
if x[4] == "S" { // South = negative.
mySituation.Lat = -mySituation.Lat
}
// field 5-6 = lon
if len(x[5]) < 11 {
return false
}
hr, err1 = strconv.Atoi(x[5][0:3])
minf, err2 = strconv.ParseFloat(x[5][3:11], 32)
if err1 != nil || err2 != nil {
return false
}
mySituation.Lng = float32(hr) + float32(minf/60.0)
if x[6] == "W" { // West = negative.
mySituation.Lng = -mySituation.Lng
}
// field 7 = height above ellipsoid, m
hae, err1 := strconv.ParseFloat(x[7], 32)
if err1 != nil {
return false
}
alt := float32(hae*3.28084) - mySituation.GeoidSep // convert to feet and offset by geoid separation
mySituation.Alt = alt
mySituation.LastFixLocalTime = stratuxClock.Time
// field 11 = groundspeed, km/h
groundspeed, err := strconv.ParseFloat(x[11], 32)
if err != nil {
return false
}
groundspeed = groundspeed * 0.540003 // convert to knots
mySituation.GroundSpeed = uint16(groundspeed)
// field 12 = track, deg
trueCourse := uint16(0)
tc, err := strconv.ParseFloat(x[12], 32)
if err != nil {
return false
}
if groundspeed > 3 { // TO-DO: use average groundspeed over last n seconds to avoid random "jumps"
trueCourse = uint16(tc)
setTrueCourse(uint16(groundspeed), trueCourse)
mySituation.TrueCourse = uint16(trueCourse)
} else {
// Negligible movement. Don't update course, but do use the slow speed.
// TO-DO: use average course over last n seconds?
}
mySituation.LastGroundTrackTime = stratuxClock.Time
// field 13 = vertical velocity, m/s
vv, err := strconv.ParseFloat(x[13], 32)
if err != nil {
return false
}
mySituation.GPSVertVel = float32(vv * -3.28084) // convert to ft/sec and positive = up
// field 14 = age of diff corrections
// field 18 = number of satellites
sat, err1 := strconv.Atoi(x[18])
if err1 != nil {
return false
}
mySituation.Satellites = uint16(sat)
} else if x[1] == "03" { // satellite status message
// field 2 = number of satellites tracked
satSeen := 0 // satellites seen (signal present)
satTracked, err := strconv.Atoi(x[2])
if err != nil {
return false
}
mySituation.SatellitesTracked = uint16(satTracked)
// fields 3-8 are repeated block
for i := 0; i < satTracked; i++ {
j := 7 + 6*i
if j < len(x) {
if x[j] != "" {
satSeen++
}
}
}
mySituation.SatellitesSeen = uint16(satSeen)
// log.Printf("Satellites with signal: %v\n",mySituation.SatellitesSeen)
/* Reference for future constellation tracking
for i:= 0; i < satTracked; i++ {
x[3+6*i] // sv number
x[4+6*i] // status [ U | e | - ] for used / ephemeris / not used
x[5+6*i] // azimuth, deg, 0-359
x[6+6*i] // elevation, deg, 0-90
x[7+6*i] // signal strength dB-Hz
x[8+6*i] // lock time, sec, 0-64
*/
} else if x[1] == "04" { // clock message
// field 5 is UTC week (epoch = 1980-JAN-06). If this is invalid, do not parse date / time
utcWeek, err0 := strconv.Atoi(x[5])
if err0 != nil {
// log.Printf("Error reading GPS week\n")
return false
}
if utcWeek < 1877 || utcWeek >= 32767 { // unless we're in a flying Delorean, UTC dates before 2016-JAN-01 are not valid. Check underflow condition as well.
log.Printf("GPS week # %v out of scope; not setting time and date\n", utcWeek)
return false
} /* else {
log.Printf("GPS week # %v valid; evaluate time and date\n", utcWeek) //debug option
} */
// field 2 is UTC time
if len(x[2]) < 9 {
return false
}
hr, err1 := strconv.Atoi(x[2][0:2])
min, err2 := strconv.Atoi(x[2][2:4])
sec, err3 := strconv.Atoi(x[2][4:6])
if err1 != nil || err2 != nil || err3 != nil {
return false
}
mySituation.lastFixSinceMidnightUTC = uint32((hr * 60 * 60) + (min * 60) + sec)
// field 3 is date
if len(x[3]) == 6 {
// Date of Fix, i.e 191115 = 19 November 2015 UTC field 9
gpsTimeStr := fmt.Sprintf("%s %02d:%02d:%02d", x[3], hr, min, sec)
gpsTime, err := time.Parse("020106 15:04:05", gpsTimeStr)
if err == nil {
// log.Printf("GPS time is: %s\n", gpsTime) //debug
if time.Since(gpsTime) > 3*time.Second || time.Since(gpsTime) < -3*time.Second {
setStr := gpsTime.Format("20060102 15:04:05.000") + " UTC"
log.Printf("setting system time to: '%s'\n", setStr)
if err := exec.Command("date", "-s", setStr).Run(); err != nil {
log.Printf("Set Date failure: %s error\n", err)
} else {
log.Printf("Time set from GPS. Current time is %v\n", time.Now())
}
}
}
}
}
// otherwise parse the NMEA standard messages as a compatibility option for SIRF, generic NMEA, etc.
} else if (x[0] == "GNVTG") || (x[0] == "GPVTG") { // Ground track information.
if len(x) < 9 { // Reduce from 10 to 9 to allow parsing by devices pre-NMEA v2.3
return false
}
mySituation.mu_GPS.Lock()
defer mySituation.mu_GPS.Unlock()
groundspeed, err := strconv.ParseFloat(x[5], 32) // Knots.
if err != nil {
return false
}
mySituation.GroundSpeed = uint16(groundspeed)
trueCourse := uint16(0)
tc, err := strconv.ParseFloat(x[1], 32)
if err != nil {
return false
}
if groundspeed > 3 { // TO-DO: use average groundspeed over last n seconds to avoid random "jumps"
trueCourse = uint16(tc)
setTrueCourse(uint16(groundspeed), trueCourse)
mySituation.TrueCourse = uint16(trueCourse)
} else {
// Negligible movement. Don't update course, but do use the slow speed.
// TO-DO: use average course over last n seconds?
}
mySituation.LastGroundTrackTime = stratuxClock.Time
} else if (x[0] == "GNGGA") || (x[0] == "GPGGA") { // GPS fix.
if len(x) < 15 {
return false
}
mySituation.mu_GPS.Lock()
defer mySituation.mu_GPS.Unlock()
// Quality indicator.
q, err1 := strconv.Atoi(x[6])
if err1 != nil {
return false
}
mySituation.quality = uint8(q) // 1 = 3D GPS; 2 = DGPS (SBAS /WAAS)
// Timestamp.
if len(x[1]) < 9 {
return false
}
hr, err1 := strconv.Atoi(x[1][0:2])
min, err2 := strconv.Atoi(x[1][2:4])
sec, err3 := strconv.Atoi(x[1][4:6])
if err1 != nil || err2 != nil || err3 != nil {
return false
}
mySituation.lastFixSinceMidnightUTC = uint32((hr * 60 * 60) + (min * 60) + sec)
// Latitude.
if len(x[2]) < 4 {
return false
}
hr, err1 = strconv.Atoi(x[2][0:2])
minf, err2 := strconv.ParseFloat(x[2][2:], 32)
if err1 != nil || err2 != nil {
return false
}
mySituation.Lat = float32(hr) + float32(minf/60.0)
if x[3] == "S" { // South = negative.
mySituation.Lat = -mySituation.Lat
}
// Longitude.
if len(x[4]) < 5 {
return false
}
hr, err1 = strconv.Atoi(x[4][0:3])
minf, err2 = strconv.ParseFloat(x[4][3:], 32)
if err1 != nil || err2 != nil {
return false
}
mySituation.Lng = float32(hr) + float32(minf/60.0)
if x[5] == "W" { // West = negative.
mySituation.Lng = -mySituation.Lng
}
/* Satellite count and horizontal accuracy deprecated. Using PUBX,00 with fallback to GSA.
// Satellites.
sat, err1 := strconv.Atoi(x[7])
if err1 != nil {
return false
}
mySituation.Satellites = uint16(sat)
// Accuracy.
hdop, err1 := strconv.ParseFloat(x[8], 32)
if err1 != nil {
return false
}
if mySituation.quality == 2 {
mySituation.Accuracy = float32(hdop * 4.0) //Estimate for WAAS / DGPS solution
} else {
mySituation.Accuracy = float32(hdop * 8.0) //Estimate for 3D non-WAAS solution
}
// NACp estimate.
mySituation.NACp = calculateNACp(mySituation.Accuracy)
*/
// Altitude.
alt, err1 := strconv.ParseFloat(x[9], 32)
if err1 != nil {
return false
}
mySituation.Alt = float32(alt * 3.28084) // Convert to feet.
// Geoid separation (Sep = HAE - MSL)
// (needed for proper MSL offset on PUBX,00 altitudes)
geoidSep, err1 := strconv.ParseFloat(x[11], 32)
if err1 != nil {
return false
}
mySituation.GeoidSep = float32(geoidSep * 3.28084) // Convert to feet.
// Timestamp.
mySituation.LastFixLocalTime = stratuxClock.Time
} else if (x[0] == "GNRMC") || (x[0] == "GPRMC") {
//$GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,230394,003.1,W*6A
/* check RY835 man for NMEA version, if >2.2, add mode field
Where:
RMC Recommended Minimum sentence C
123519 Fix taken at 12:35:19 UTC
A Status A=active or V=Void.
4807.038,N Latitude 48 deg 07.038' N
01131.000,E Longitude 11 deg 31.000' E
022.4 Speed over the ground in knots
084.4 Track angle in degrees True
230394 Date - 23rd of March 1994
003.1,W Magnetic Variation
D mode field (nmea 2.3 and higher)
*6A The checksum data, always begins with *
*/
if len(x) < 12 {
return false
}
mySituation.mu_GPS.Lock()
defer mySituation.mu_GPS.Unlock()
if x[2] != "A" { // invalid fix
mySituation.quality = 0
return false
} else if mySituation.quality == 0 {
mySituation.quality = 1 // fallback option; indicate if the position fix is valid even if GGA or PUBX,00 aren't received
}
// Timestamp.
if len(x[1]) < 9 {
return false
}
hr, err1 := strconv.Atoi(x[1][0:2])
min, err2 := strconv.Atoi(x[1][2:4])
sec, err3 := strconv.Atoi(x[1][4:6])
if err1 != nil || err2 != nil || err3 != nil {
return false
}
mySituation.lastFixSinceMidnightUTC = uint32((hr * 60 * 60) + (min * 60) + sec)
if len(x[9]) == 6 {
// Date of Fix, i.e 191115 = 19 November 2015 UTC field 9
gpsTimeStr := fmt.Sprintf("%s %02d:%02d:%02d", x[9], hr, min, sec)
gpsTime, err := time.Parse("020106 15:04:05", gpsTimeStr)
if err == nil {
if time.Since(gpsTime) > 3*time.Second || time.Since(gpsTime) < -3*time.Second {
setStr := gpsTime.Format("20060102 15:04:05.000") + " UTC"
log.Printf("setting system time to: '%s'\n", setStr)
if err := exec.Command("date", "-s", setStr).Run(); err != nil {
log.Printf("Set Date failure: %s error\n", err)
} else {
log.Printf("Time set from GPS. Current time is %v\n", time.Now())
}
}
}
}
// Latitude.
if len(x[3]) < 4 {
return false
}
hr, err1 = strconv.Atoi(x[3][0:2])
minf, err2 := strconv.ParseFloat(x[3][2:], 32)
if err1 != nil || err2 != nil {
return false
}
mySituation.Lat = float32(hr) + float32(minf/60.0)
if x[4] == "S" { // South = negative.
mySituation.Lat = -mySituation.Lat
}
// Longitude.
if len(x[5]) < 5 {
return false
}
hr, err1 = strconv.Atoi(x[5][0:3])
minf, err2 = strconv.ParseFloat(x[5][3:], 32)
if err1 != nil || err2 != nil {
return false
}
mySituation.Lng = float32(hr) + float32(minf/60.0)
if x[6] == "W" { // West = negative.
mySituation.Lng = -mySituation.Lng
}
mySituation.LastFixLocalTime = stratuxClock.Time
// ground speed in kts (field 7)
groundspeed, err := strconv.ParseFloat(x[7], 32)
if err != nil {
return false
}
mySituation.GroundSpeed = uint16(groundspeed)
// ground track "True" (field 8)
trueCourse := uint16(0)
tc, err := strconv.ParseFloat(x[8], 32)
if err != nil {
return false
}
if groundspeed > 3 { // TO-DO: use average groundspeed over last n seconds to avoid random "jumps"
trueCourse = uint16(tc)
setTrueCourse(uint16(groundspeed), trueCourse)
mySituation.TrueCourse = uint16(trueCourse)
} else {
// Negligible movement. Don't update course, but do use the slow speed.
// TO-DO: use average course over last n seconds?
}
mySituation.LastGroundTrackTime = stratuxClock.Time
} else if (x[0] == "GNGSA") || (x[0] == "GPGSA") {
if len(x) < 18 {
return false
}
// field 1: operation mode
// M: manual forced to 2D or 3D mode
// A: automatic switching between 2D and 3D modes
if (x[1] != "A") && (x[1] != "M") { // invalid fix
mySituation.quality = 0
return false
}
// field 2: solution type
// 1 = no solution; 2 = 2D fix, 3 = 3D fix. WAAS status is parsed from GGA message, so no need to get here
// fields 3-14: satellites in solution
sat := 0
for _, svtxt := range x[3:15] {
_, err := strconv.Atoi(svtxt)
if err == nil {
sat++
}
}
mySituation.Satellites = uint16(sat)
// Satellites tracked / seen should be parsed from GSV message (TO-DO) ... since we don't have it, just use satellites from solution
if mySituation.SatellitesTracked == 0 {
mySituation.SatellitesTracked = uint16(sat)
}
if mySituation.SatellitesSeen == 0 {
mySituation.SatellitesSeen = uint16(sat)
}
// field 16: HDOP
// Accuracy estimate
hdop, err1 := strconv.ParseFloat(x[16], 32)
if err1 != nil {
return false
}
if mySituation.quality == 2 {
mySituation.Accuracy = float32(hdop * 4.0) // Rough 95% confidence estimate for WAAS / DGPS solution
} else {
mySituation.Accuracy = float32(hdop * 8.0) // Rough 95% confidence estimate for 3D non-WAAS solution
}
// NACp estimate.
mySituation.NACp = calculateNACp(mySituation.Accuracy)
// field 17: VDOP
// accuracy estimate
vdop, err1 := strconv.ParseFloat(x[17], 32)
if err1 != nil {
return false
}
mySituation.AccuracyVert = float32(vdop * 5) // rough estimate for 95% confidence
}
return true
}
func gpsSerialReader() {
defer serialPort.Close()
readyToInitGPS = false // TO-DO: replace with channel control to terminate goroutine when complete
i := 0 //debug monitor
scanner := bufio.NewScanner(serialPort)
for scanner.Scan() && globalStatus.GPS_connected && globalSettings.GPS_Enabled {
i++
if i%100 == 0 {
log.Printf("gpsSerialReader() scanner loop iteration i=%d\n", i) // debug monitor
}
s := scanner.Text()
//fmt.Printf("Output: %s\n", s)
if !(processNMEALine(s)) {
// fmt.Printf("processNMEALine() exited early -- %s\n",s) //debug code. comment out before pushing to github
}
}
if err := scanner.Err(); err != nil {
log.Printf("reading standard input: %s\n", err.Error())
}
log.Printf("Exiting gpsSerialReader() after i=%d loops\n", i) // debug monitor
globalStatus.GPS_connected = false
readyToInitGPS = true // TO-DO: replace with channel control to terminate goroutine when complete
return
}
var i2cbus embd.I2CBus
var myBMP180 *bmp180.BMP180
var myMPU6050 *mpu6050.MPU6050
func readBMP180() (float64, float64, error) { // ºCelsius, Meters
temp, err := myBMP180.Temperature()
if err != nil {
return temp, 0.0, err
}
altitude, err := myBMP180.Altitude()
altitude = float64(1/0.3048) * altitude // Convert meters to feet.
if err != nil {
return temp, altitude, err
}
return temp, altitude, nil
}
func readMPU6050() (float64, float64, error) { //TODO: error checking.
pitch, roll := myMPU6050.PitchAndRoll()
return pitch, roll, nil
}
func initBMP180() error {
myBMP180 = bmp180.New(i2cbus) //TODO: error checking.
return nil
}
func initMPU6050() error {
myMPU6050 = mpu6050.New() //TODO: error checking.
return nil
}
func initI2C() error {
i2cbus = embd.NewI2CBus(1) //TODO: error checking.
return nil
}
// Unused at the moment. 5 second update, since read functions in bmp180 are slow.
func tempAndPressureReader() {
timer := time.NewTicker(5 * time.Second)
for globalStatus.RY835AI_connected && globalSettings.AHRS_Enabled {
<-timer.C
// Read temperature and pressure altitude.
temp, alt, err_bmp180 := readBMP180()
// Process.
if err_bmp180 != nil {
log.Printf("readBMP180(): %s\n", err_bmp180.Error())
globalStatus.RY835AI_connected = false
} else {
mySituation.Temp = temp
mySituation.Pressure_alt = alt
mySituation.lastTempPressTime = stratuxClock.Time
}
}
globalStatus.RY835AI_connected = false
}
func makeFFAHRSSimReport() {
s := fmt.Sprintf("XATTStratux,%f,%f,%f", mySituation.Gyro_heading, mySituation.Pitch, mySituation.Roll)
sendMsg([]byte(s), NETWORK_AHRS_FFSIM, false)
}
func makeAHRSGDL90Report() {
msg := make([]byte, 16)
msg[0] = 0x4c
msg[1] = 0x45
msg[2] = 0x01
msg[3] = 0x00
pitch := int16(float64(mySituation.Pitch) * float64(10.0))
roll := int16(float64(mySituation.Roll) * float64(10.0))
hdg := uint16(float64(mySituation.Gyro_heading) * float64(10.0)) //TODO.
slip_skid := int16(float64(0) * float64(10.0)) //TODO.
yaw_rate := int16(float64(0) * float64(10.0)) //TODO.
g := int16(float64(1.0) * float64(10.0)) //TODO.
// Roll.
msg[4] = byte((roll >> 8) & 0xFF)
msg[5] = byte(roll & 0xFF)
// Pitch.
msg[6] = byte((pitch >> 8) & 0xFF)
msg[7] = byte(pitch & 0xFF)
// Heading.
msg[8] = byte((hdg >> 8) & 0xFF)
msg[9] = byte(hdg & 0xFF)
// Slip/skid.
msg[10] = byte((slip_skid >> 8) & 0xFF)
msg[11] = byte(slip_skid & 0xFF)
// Yaw rate.
msg[12] = byte((yaw_rate >> 8) & 0xFF)
msg[13] = byte(yaw_rate & 0xFF)
// "G".
msg[14] = byte((g >> 8) & 0xFF)
msg[15] = byte(g & 0xFF)
sendMsg(prepareMessage(msg), NETWORK_AHRS_GDL90, false)
}
func attitudeReaderSender() {
timer := time.NewTicker(100 * time.Millisecond) // ~10Hz update.
for globalStatus.RY835AI_connected && globalSettings.AHRS_Enabled {
<-timer.C
// Read pitch and roll.
pitch, roll, err_mpu6050 := readMPU6050()
if err_mpu6050 != nil {
log.Printf("readMPU6050(): %s\n", err_mpu6050.Error())
globalStatus.RY835AI_connected = false
break
}
mySituation.mu_Attitude.Lock()
mySituation.Pitch = pitch
mySituation.Roll = roll
mySituation.Gyro_heading = myMPU6050.Heading() //FIXME. Experimental.
mySituation.LastAttitudeTime = stratuxClock.Time
// Send, if valid.
// if isGPSGroundTrackValid(), etc.
// makeFFAHRSSimReport() // simultaneous use of GDL90 and FFSIM not supported in FF 7.5.1 or later. Function definition will be kept for AHRS debugging and future workarounds.
makeAHRSGDL90Report()
mySituation.mu_Attitude.Unlock()
}
globalStatus.RY835AI_connected = false
}
func isGPSConnected() bool {
return stratuxClock.Since(mySituation.LastNMEAMessage) < 5*time.Second
}
func isGPSValid() bool {
return stratuxClock.Since(mySituation.LastFixLocalTime) < 15*time.Second
}
func isGPSGroundTrackValid() bool {
return stratuxClock.Since(mySituation.LastGroundTrackTime) < 15*time.Second
}
func isAHRSValid() bool {
return stratuxClock.Since(mySituation.LastAttitudeTime) < 1*time.Second // If attitude information gets to be over 1 second old, declare invalid.
}
func isTempPressValid() bool {
return stratuxClock.Since(mySituation.lastTempPressTime) < 15*time.Second
}
func initAHRS() error {
if err := initI2C(); err != nil { // I2C bus.
return err
}
if err := initBMP180(); err != nil { // I2C temperature and pressure altitude.
i2cbus.Close()
return err
}
if err := initMPU6050(); err != nil { // I2C accel/gyro.
i2cbus.Close()
myBMP180.Close()
return err
}
globalStatus.RY835AI_connected = true
go attitudeReaderSender()
go tempAndPressureReader()
return nil
}
func pollRY835AI() {
readyToInitGPS = true //TO-DO: Implement more robust method (channel control) to kill zombie serial readers
timer := time.NewTicker(4 * time.Second)
for {
<-timer.C
// GPS enabled, was not connected previously?
if globalSettings.GPS_Enabled && !globalStatus.GPS_connected && readyToInitGPS { //TO-DO: Implement more robust method (channel control) to kill zombie serial readers
globalStatus.GPS_connected = initGPSSerial()
if globalStatus.GPS_connected {
go gpsSerialReader()
}
}
// RY835AI I2C enabled, was not connected previously?
if globalSettings.AHRS_Enabled && !globalStatus.RY835AI_connected {
err := initAHRS()
if err != nil {
log.Printf("initAHRS(): %s\ndisabling AHRS sensors.\n", err.Error())
globalStatus.RY835AI_connected = false
}
}
}
}
func initRY835AI() {
mySituation.mu_GPS = &sync.Mutex{}
mySituation.mu_Attitude = &sync.Mutex{}
go pollRY835AI()
}