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ardupilot/libraries/SITL/SIM_GPS.cpp

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/*
SITL handling
This simulates a GPS on a serial port
Andrew Tridgell November 2011
*/
#include "SIM_GPS.h"
#if HAL_SIM_GPS_ENABLED
#include <time.h>
#include <assert.h>
#include <AP_BoardConfig/AP_BoardConfig.h>
#include <AP_HAL/AP_HAL.h>
#include <SITL/SITL.h>
#include <AP_InternalError/AP_InternalError.h>
#include <AP_Common/NMEA.h>
#include <AP_HAL/utility/sparse-endian.h>
// the number of GPS leap seconds - copied from AP_GPS.h
#define GPS_LEAPSECONDS_MILLIS 18000ULL
extern const AP_HAL::HAL& hal;
using namespace SITL;
struct GPS_TOW {
// Number of weeks since midnight 5-6 January 1980
uint16_t week;
// Time since start of the GPS week [mS]
uint32_t ms;
};
// ensure the backend we have allocated matches the one that's configured:
GPS_Backend::GPS_Backend(GPS &_front, uint8_t _instance)
: front{_front},
instance{_instance}
{
}
ssize_t GPS_Backend::write_to_autopilot(const char *p, size_t size) const
{
return front.write_to_autopilot(p, size);
}
ssize_t GPS_Backend::read_from_autopilot(char *buffer, size_t size) const
{
return front.read_from_autopilot(buffer, size);
}
void GPS_Backend::update(const GPS_Data &d)
{
if (_sitl == nullptr) {
_sitl = AP::sitl();
if (_sitl == nullptr) {
return;
}
}
update_read(&d);
update_write(&d);
}
GPS::GPS(uint8_t _instance) :
SerialDevice(8192, 2048),
instance{_instance}
{
}
uint32_t GPS::device_baud() const
{
if (backend == nullptr) {
return 0;
}
return backend->device_baud();
}
/*
write some bytes from the simulated GPS
*/
ssize_t GPS::write_to_autopilot(const char *p, size_t size) const
{
// the second GPS instance fails in a different way to the first;
// the first will start sending back 3 satellites, the second just
// stops responding when disabled. This is not necessarily a good
// thing.
if (instance == 1 && _sitl->gps_disable[instance]) {
return -1;
}
const float byteloss = _sitl->gps_byteloss[instance];
// shortcut if we're not doing byteloss:
if (!is_positive(byteloss)) {
return SerialDevice::write_to_autopilot(p, size);
}
size_t ret = 0;
while (size--) {
float r = ((((unsigned)random()) % 1000000)) / 1.0e4;
if (r < byteloss) {
// lose the byte
p++;
continue;
}
const ssize_t pret = SerialDevice::write_to_autopilot(p, 1);
if (pret == 0) {
// no space?
return ret;
}
if (pret != 1) {
// error has occured?
return pret;
}
ret++;
p++;
}
return ret;
}
/*
get timeval using simulation time
*/
static void simulation_timeval(struct timeval *tv)
{
uint64_t now = AP_HAL::micros64();
static uint64_t first_usec;
static struct timeval first_tv;
if (first_usec == 0) {
first_usec = now;
first_tv.tv_sec = AP::sitl()->start_time_UTC;
}
*tv = first_tv;
tv->tv_sec += now / 1000000ULL;
uint64_t new_usec = tv->tv_usec + (now % 1000000ULL);
tv->tv_sec += new_usec / 1000000ULL;
tv->tv_usec = new_usec % 1000000ULL;
}
/*
send a UBLOX GPS message
*/
void GPS_UBlox::send_ubx(uint8_t msgid, uint8_t *buf, uint16_t size)
{
const uint8_t PREAMBLE1 = 0xb5;
const uint8_t PREAMBLE2 = 0x62;
const uint8_t CLASS_NAV = 0x1;
uint8_t hdr[6], chk[2];
hdr[0] = PREAMBLE1;
hdr[1] = PREAMBLE2;
hdr[2] = CLASS_NAV;
hdr[3] = msgid;
hdr[4] = size & 0xFF;
hdr[5] = size >> 8;
chk[0] = chk[1] = hdr[2];
chk[1] += (chk[0] += hdr[3]);
chk[1] += (chk[0] += hdr[4]);
chk[1] += (chk[0] += hdr[5]);
for (uint16_t i=0; i<size; i++) {
chk[1] += (chk[0] += buf[i]);
}
write_to_autopilot((char*)hdr, sizeof(hdr));
write_to_autopilot((char*)buf, size);
write_to_autopilot((char*)chk, sizeof(chk));
}
/*
return GPS time of week
*/
static GPS_TOW gps_time()
{
GPS_TOW gps_tow;
struct timeval tv;
simulation_timeval(&tv);
const uint32_t epoch = 86400*(10*365 + (1980-1969)/4 + 1 + 6 - 2) - (GPS_LEAPSECONDS_MILLIS / 1000ULL);
uint32_t epoch_seconds = tv.tv_sec - epoch;
gps_tow.week = epoch_seconds / AP_SEC_PER_WEEK;
uint32_t t_ms = tv.tv_usec / 1000;
// round time to nearest 200ms
gps_tow.ms = (epoch_seconds % AP_SEC_PER_WEEK) * AP_MSEC_PER_SEC + ((t_ms/200) * 200);
return gps_tow;
}
/*
send a new set of GPS UBLOX packets
*/
void GPS_UBlox::update_write(const GPS_Data *d)
{
struct PACKED ubx_nav_posllh {
uint32_t time; // GPS msToW
int32_t longitude;
int32_t latitude;
int32_t altitude_ellipsoid;
int32_t altitude_msl;
uint32_t horizontal_accuracy;
uint32_t vertical_accuracy;
} pos {};
struct PACKED ubx_nav_status {
uint32_t time; // GPS msToW
uint8_t fix_type;
uint8_t fix_status;
uint8_t differential_status;
uint8_t res;
uint32_t time_to_first_fix;
uint32_t uptime; // milliseconds
} status {};
struct PACKED ubx_nav_velned {
uint32_t time; // GPS msToW
int32_t ned_north;
int32_t ned_east;
int32_t ned_down;
uint32_t speed_3d;
uint32_t speed_2d;
int32_t heading_2d;
uint32_t speed_accuracy;
uint32_t heading_accuracy;
} velned {};
struct PACKED ubx_nav_solution {
uint32_t time;
int32_t time_nsec;
int16_t week;
uint8_t fix_type;
uint8_t fix_status;
int32_t ecef_x;
int32_t ecef_y;
int32_t ecef_z;
uint32_t position_accuracy_3d;
int32_t ecef_x_velocity;
int32_t ecef_y_velocity;
int32_t ecef_z_velocity;
uint32_t speed_accuracy;
uint16_t position_DOP;
uint8_t res;
uint8_t satellites;
uint32_t res2;
} sol {};
struct PACKED ubx_nav_dop {
uint32_t time; // GPS msToW
uint16_t gDOP;
uint16_t pDOP;
uint16_t tDOP;
uint16_t vDOP;
uint16_t hDOP;
uint16_t nDOP;
uint16_t eDOP;
} dop {};
struct PACKED ubx_nav_pvt {
uint32_t itow;
uint16_t year;
uint8_t month, day, hour, min, sec;
uint8_t valid;
uint32_t t_acc;
int32_t nano;
uint8_t fix_type;
uint8_t flags;
uint8_t flags2;
uint8_t num_sv;
int32_t lon, lat;
int32_t height, h_msl;
uint32_t h_acc, v_acc;
int32_t velN, velE, velD, gspeed;
int32_t head_mot;
uint32_t s_acc;
uint32_t head_acc;
uint16_t p_dop;
uint8_t reserved1[6];
uint32_t headVeh;
uint8_t reserved2[4];
} pvt {};
const uint8_t SV_COUNT = 10;
struct PACKED ubx_nav_svinfo {
uint32_t itow;
uint8_t numCh;
uint8_t globalFlags;
uint8_t reserved1[2];
// repeated block
struct PACKED svinfo_sv {
uint8_t chn;
uint8_t svid;
uint8_t flags;
uint8_t quality;
uint8_t cno;
int8_t elev;
int16_t azim;
int32_t prRes;
} sv[SV_COUNT];
} svinfo {};
enum RELPOSNED {
gnssFixOK = 1U << 0,
diffSoln = 1U << 1,
relPosValid = 1U << 2,
carrSolnFloat = 1U << 3,
carrSolnFixed = 1U << 4,
isMoving = 1U << 5,
refPosMiss = 1U << 6,
refObsMiss = 1U << 7,
relPosHeadingValid = 1U << 8,
relPosNormalized = 1U << 9
};
struct PACKED ubx_nav_relposned {
uint8_t version;
uint8_t reserved1;
uint16_t refStationId;
uint32_t iTOW;
int32_t relPosN;
int32_t relPosE;
int32_t relPosD;
int32_t relPosLength;
int32_t relPosHeading;
uint8_t reserved2[4];
int8_t relPosHPN;
int8_t relPosHPE;
int8_t relPosHPD;
int8_t relPosHPLength;
uint32_t accN;
uint32_t accE;
uint32_t accD;
uint32_t accLength;
uint32_t accHeading;
uint8_t reserved3[4];
uint32_t flags;
} relposned {};
const uint8_t MSG_POSLLH = 0x2;
const uint8_t MSG_STATUS = 0x3;
const uint8_t MSG_DOP = 0x4;
const uint8_t MSG_VELNED = 0x12;
const uint8_t MSG_SOL = 0x6;
const uint8_t MSG_PVT = 0x7;
const uint8_t MSG_SVINFO = 0x30;
const uint8_t MSG_RELPOSNED = 0x3c;
uint32_t _next_nav_sv_info_time = 0;
const auto gps_tow = gps_time();
pos.time = gps_tow.ms;
pos.longitude = d->longitude * 1.0e7;
pos.latitude = d->latitude * 1.0e7;
pos.altitude_ellipsoid = d->altitude * 1000.0f;
pos.altitude_msl = d->altitude * 1000.0f;
pos.horizontal_accuracy = _sitl->gps_accuracy[instance]*1000;
pos.vertical_accuracy = _sitl->gps_accuracy[instance]*1000;
status.time = gps_tow.ms;
status.fix_type = d->have_lock?3:0;
status.fix_status = d->have_lock?1:0;
status.differential_status = 0;
status.res = 0;
status.time_to_first_fix = 0;
status.uptime = AP_HAL::millis();
velned.time = gps_tow.ms;
velned.ned_north = 100.0f * d->speedN;
velned.ned_east = 100.0f * d->speedE;
velned.ned_down = 100.0f * d->speedD;
velned.speed_2d = norm(d->speedN, d->speedE) * 100;
velned.speed_3d = norm(d->speedN, d->speedE, d->speedD) * 100;
velned.heading_2d = ToDeg(atan2f(d->speedE, d->speedN)) * 100000.0f;
if (velned.heading_2d < 0.0f) {
velned.heading_2d += 360.0f * 100000.0f;
}
velned.speed_accuracy = 40;
velned.heading_accuracy = 4;
memset(&sol, 0, sizeof(sol));
sol.fix_type = d->have_lock?3:0;
sol.fix_status = 221;
sol.satellites = d->have_lock ? _sitl->gps_numsats[instance] : 3;
sol.time = gps_tow.ms;
sol.week = gps_tow.week;
dop.time = gps_tow.ms;
dop.gDOP = 65535;
dop.pDOP = 65535;
dop.tDOP = 65535;
dop.vDOP = 200;
dop.hDOP = 121;
dop.nDOP = 65535;
dop.eDOP = 65535;
pvt.itow = gps_tow.ms;
pvt.year = 0;
pvt.month = 0;
pvt.day = 0;
pvt.hour = 0;
pvt.min = 0;
pvt.sec = 0;
pvt.valid = 0; // invalid utc date
pvt.t_acc = 0;
pvt.nano = 0;
pvt.fix_type = d->have_lock? 0x3 : 0;
pvt.flags = 0b10000011; // carrsoln=fixed, psm = na, diffsoln and fixok
pvt.flags2 =0;
pvt.num_sv = d->have_lock ? _sitl->gps_numsats[instance] : 3;
pvt.lon = d->longitude * 1.0e7;
pvt.lat = d->latitude * 1.0e7;
pvt.height = d->altitude * 1000.0f;
pvt.h_msl = d->altitude * 1000.0f;
pvt.h_acc = _sitl->gps_accuracy[instance] * 1000;
pvt.v_acc = _sitl->gps_accuracy[instance] * 1000;
pvt.velN = 1000.0f * d->speedN;
pvt.velE = 1000.0f * d->speedE;
pvt.velD = 1000.0f * d->speedD;
pvt.gspeed = norm(d->speedN, d->speedE) * 1000;
pvt.head_mot = ToDeg(atan2f(d->speedE, d->speedN)) * 1.0e5;
pvt.s_acc = 40;
pvt.head_acc = 38 * 1.0e5;
pvt.p_dop = 65535;
memset(pvt.reserved1, '\0', ARRAY_SIZE(pvt.reserved1));
pvt.headVeh = 0;
memset(pvt.reserved2, '\0', ARRAY_SIZE(pvt.reserved2));
if (_sitl->gps_hdg_enabled[instance] > SITL::SIM::GPS_HEADING_NONE) {
const Vector3f ant1_pos = _sitl->gps_pos_offset[instance^1].get();
const Vector3f ant2_pos = _sitl->gps_pos_offset[instance].get();
Vector3f rel_antenna_pos = ant2_pos - ant1_pos;
Matrix3f rot;
// project attitude back using gyros to get antenna orientation at time of GPS sample
Vector3f gyro(radians(_sitl->state.rollRate),
radians(_sitl->state.pitchRate),
radians(_sitl->state.yawRate));
rot.from_euler(radians(_sitl->state.rollDeg), radians(_sitl->state.pitchDeg), radians(d->yaw_deg));
const float lag = _sitl->gps_delay_ms[instance] * 0.001;
rot.rotate(gyro * (-lag));
rel_antenna_pos = rot * rel_antenna_pos;
relposned.version = 1;
relposned.iTOW = gps_tow.ms;
relposned.relPosN = rel_antenna_pos.x * 100;
relposned.relPosE = rel_antenna_pos.y * 100;
relposned.relPosD = rel_antenna_pos.z * 100;
relposned.relPosLength = rel_antenna_pos.length() * 100;
relposned.relPosHeading = degrees(Vector2f(rel_antenna_pos.x, rel_antenna_pos.y).angle()) * 1.0e5;
relposned.flags = gnssFixOK | diffSoln | carrSolnFixed | isMoving | relPosValid | relPosHeadingValid;
}
send_ubx(MSG_POSLLH, (uint8_t*)&pos, sizeof(pos));
send_ubx(MSG_STATUS, (uint8_t*)&status, sizeof(status));
send_ubx(MSG_VELNED, (uint8_t*)&velned, sizeof(velned));
send_ubx(MSG_SOL, (uint8_t*)&sol, sizeof(sol));
send_ubx(MSG_DOP, (uint8_t*)&dop, sizeof(dop));
send_ubx(MSG_PVT, (uint8_t*)&pvt, sizeof(pvt));
if (_sitl->gps_hdg_enabled[instance] > SITL::SIM::GPS_HEADING_NONE) {
send_ubx(MSG_RELPOSNED, (uint8_t*)&relposned, sizeof(relposned));
}
if (gps_tow.ms > _next_nav_sv_info_time) {
svinfo.itow = gps_tow.ms;
svinfo.numCh = 32;
svinfo.globalFlags = 4; // u-blox 8/M8
// fill in the SV's with some data even though firmware does not currently use it
// note that this is not using num_sats as we aren't dynamically creating this to match
for (uint8_t i = 0; i < SV_COUNT; i++) {
svinfo.sv[i].chn = i;
svinfo.sv[i].svid = i;
svinfo.sv[i].flags = (i < _sitl->gps_numsats[instance]) ? 0x7 : 0x6; // sv used, diff correction data, orbit information
svinfo.sv[i].quality = 7; // code and carrier lock and time synchronized
svinfo.sv[i].cno = MAX(20, 30 - i);
svinfo.sv[i].elev = MAX(30, 90 - i);
svinfo.sv[i].azim = i;
// not bothering to fill in prRes
}
send_ubx(MSG_SVINFO, (uint8_t*)&svinfo, sizeof(svinfo));
_next_nav_sv_info_time = gps_tow.ms + 10000; // 10 second delay
}
}
/*
formatted print of NMEA message, with checksum appended
*/
void GPS_NMEA::nmea_printf(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
char *s = nmea_vaprintf(fmt, ap);
va_end(ap);
if (s != nullptr) {
write_to_autopilot((const char*)s, strlen(s));
free(s);
}
}
/*
send a new GPS NMEA packet
*/
void GPS_NMEA::update_write(const GPS_Data *d)
{
struct timeval tv;
struct tm *tm;
char tstring[20];
char dstring[20];
char lat_string[20];
char lng_string[20];
simulation_timeval(&tv);
tm = gmtime(&tv.tv_sec);
// format time string
snprintf(tstring, sizeof(tstring), "%02u%02u%06.3f", tm->tm_hour, tm->tm_min, tm->tm_sec + tv.tv_usec*1.0e-6);
// format date string
snprintf(dstring, sizeof(dstring), "%02u%02u%02u", tm->tm_mday, tm->tm_mon+1, tm->tm_year % 100);
// format latitude
double deg = fabs(d->latitude);
snprintf(lat_string, sizeof(lat_string), "%02u%08.5f,%c",
(unsigned)deg,
(deg - int(deg))*60,
d->latitude<0?'S':'N');
// format longitude
deg = fabs(d->longitude);
snprintf(lng_string, sizeof(lng_string), "%03u%08.5f,%c",
(unsigned)deg,
(deg - int(deg))*60,
d->longitude<0?'W':'E');
nmea_printf("$GPGGA,%s,%s,%s,%01d,%02d,%04.1f,%07.2f,M,0.0,M,,",
tstring,
lat_string,
lng_string,
d->have_lock?1:0,
d->have_lock?_sitl->gps_numsats[instance]:3,
1.2,
d->altitude);
const float speed_mps = d->speed_2d();
const float speed_knots = speed_mps * M_PER_SEC_TO_KNOTS;
const auto heading_rad = d->heading();
//$GPVTG,133.18,T,120.79,M,0.11,N,0.20,K,A*24
nmea_printf("$GPVTG,%.2f,T,%.2f,M,%.2f,N,%.2f,K,A",
tstring,
heading_rad,
heading_rad,
speed_knots,
speed_knots * KNOTS_TO_METERS_PER_SECOND * 3.6);
nmea_printf("$GPRMC,%s,%c,%s,%s,%.2f,%.2f,%s,,",
tstring,
d->have_lock?'A':'V',
lat_string,
lng_string,
speed_knots,
heading_rad,
dstring);
if (_sitl->gps_hdg_enabled[instance] == SITL::SIM::GPS_HEADING_HDT) {
nmea_printf("$GPHDT,%.2f,T", d->yaw_deg);
}
else if (_sitl->gps_hdg_enabled[instance] == SITL::SIM::GPS_HEADING_THS) {
nmea_printf("$GPTHS,%.2f,%c,T", d->yaw_deg, d->have_lock ? 'A' : 'V');
} else if (_sitl->gps_hdg_enabled[instance] == SITL::SIM::GPS_HEADING_KSXT) {
// Unicore support
// $KSXT,20211016083433.00,116.31296102,39.95817066,49.4911,223.57,-11.32,330.19,0.024,,1,3,28,27,,,,-0.012,0.021,0.020,,*2D
nmea_printf("$KSXT,%04u%02u%02u%02u%02u%02u.%02u,%.8f,%.8f,%.4f,%.2f,%.2f,%.2f,%.2f,%.3f,%u,%u,%u,%u,,,,%.3f,%.3f,%.3f,,",
tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec, unsigned(tv.tv_usec*1.e-4),
d->longitude, d->latitude,
d->altitude,
wrap_360(d->yaw_deg),
d->pitch_deg,
heading_rad,
speed_mps,
d->roll_deg,
d->have_lock?1:0, // 2=rtkfloat 3=rtkfixed,
3, // fixed rtk yaw solution,
d->have_lock?_sitl->gps_numsats[instance]:3,
d->have_lock?_sitl->gps_numsats[instance]:3,
d->speedE * 3.6,
d->speedN * 3.6,
-d->speedD * 3.6);
}
}
void GPS_SBP_Common::sbp_send_message(uint16_t msg_type, uint16_t sender_id, uint8_t len, uint8_t *payload)
{
if (len != 0 && payload == 0) {
return; //SBP_NULL_ERROR;
}
uint8_t preamble = 0x55;
write_to_autopilot((char*)&preamble, 1);
write_to_autopilot((char*)&msg_type, 2);
write_to_autopilot((char*)&sender_id, 2);
write_to_autopilot((char*)&len, 1);
if (len > 0) {
write_to_autopilot((char*)payload, len);
}
uint16_t crc;
crc = crc16_ccitt((uint8_t*)&(msg_type), 2, 0);
crc = crc16_ccitt((uint8_t*)&(sender_id), 2, crc);
crc = crc16_ccitt(&(len), 1, crc);
crc = crc16_ccitt(payload, len, crc);
write_to_autopilot((char*)&crc, 2);
}
void GPS_SBP::update_write(const GPS_Data *d)
{
struct sbp_heartbeat_t {
bool sys_error : 1;
bool io_error : 1;
bool nap_error : 1;
uint8_t res : 5;
uint8_t protocol_minor : 8;
uint8_t protocol_major : 8;
uint8_t res2 : 7;
bool ext_antenna : 1;
} hb; // 4 bytes
struct PACKED sbp_gps_time_t {
uint16_t wn; //< GPS week number
uint32_t tow; //< GPS Time of Week rounded to the nearest ms
int32_t ns; //< Nanosecond remainder of rounded tow
uint8_t flags; //< Status flags (reserved)
} t;
struct PACKED sbp_pos_llh_t {
uint32_t tow; //< GPS Time of Week
double lat; //< Latitude
double lon; //< Longitude
double height; //< Height
uint16_t h_accuracy; //< Horizontal position accuracy estimate
uint16_t v_accuracy; //< Vertical position accuracy estimate
uint8_t n_sats; //< Number of satellites used in solution
uint8_t flags; //< Status flags
} pos;
struct PACKED sbp_vel_ned_t {
uint32_t tow; //< GPS Time of Week
int32_t n; //< Velocity North coordinate
int32_t e; //< Velocity East coordinate
int32_t d; //< Velocity Down coordinate
uint16_t h_accuracy; //< Horizontal velocity accuracy estimate
uint16_t v_accuracy; //< Vertical velocity accuracy estimate
uint8_t n_sats; //< Number of satellites used in solution
uint8_t flags; //< Status flags (reserved)
} velned;
struct PACKED sbp_dops_t {
uint32_t tow; //< GPS Time of Week
uint16_t gdop; //< Geometric Dilution of Precision
uint16_t pdop; //< Position Dilution of Precision
uint16_t tdop; //< Time Dilution of Precision
uint16_t hdop; //< Horizontal Dilution of Precision
uint16_t vdop; //< Vertical Dilution of Precision
uint8_t flags; //< Status flags (reserved)
} dops;
static const uint16_t SBP_HEARTBEAT_MSGTYPE = 0xFFFF;
static const uint16_t SBP_GPS_TIME_MSGTYPE = 0x0100;
static const uint16_t SBP_DOPS_MSGTYPE = 0x0206;
static const uint16_t SBP_POS_LLH_MSGTYPE = 0x0201;
static const uint16_t SBP_VEL_NED_MSGTYPE = 0x0205;
const auto gps_tow = gps_time();
t.wn = gps_tow.week;
t.tow = gps_tow.ms;
t.ns = 0;
t.flags = 0;
sbp_send_message(SBP_GPS_TIME_MSGTYPE, 0x2222, sizeof(t), (uint8_t*)&t);
if (!d->have_lock) {
return;
}
pos.tow = gps_tow.ms;
pos.lon = d->longitude;
pos.lat= d->latitude;
pos.height = d->altitude;
pos.h_accuracy = _sitl->gps_accuracy[instance]*1000;
pos.v_accuracy = _sitl->gps_accuracy[instance]*1000;
pos.n_sats = d->have_lock ? _sitl->gps_numsats[instance] : 3;
// Send single point position solution
pos.flags = 0;
sbp_send_message(SBP_POS_LLH_MSGTYPE, 0x2222, sizeof(pos), (uint8_t*)&pos);
// Send "pseudo-absolute" RTK position solution
pos.flags = 1;
sbp_send_message(SBP_POS_LLH_MSGTYPE, 0x2222, sizeof(pos), (uint8_t*)&pos);
velned.tow = gps_tow.ms;
velned.n = 1e3 * d->speedN;
velned.e = 1e3 * d->speedE;
velned.d = 1e3 * d->speedD;
velned.h_accuracy = 5e3;
velned.v_accuracy = 5e3;
velned.n_sats = d->have_lock ? _sitl->gps_numsats[instance] : 3;
velned.flags = 0;
sbp_send_message(SBP_VEL_NED_MSGTYPE, 0x2222, sizeof(velned), (uint8_t*)&velned);
static uint32_t do_every_count = 0;
if (do_every_count % 5 == 0) {
dops.tow = gps_tow.ms;
dops.gdop = 1;
dops.pdop = 1;
dops.tdop = 1;
dops.hdop = 100;
dops.vdop = 1;
dops.flags = 1;
sbp_send_message(SBP_DOPS_MSGTYPE, 0x2222, sizeof(dops),
(uint8_t*)&dops);
hb.protocol_major = 0; //Sends protocol version 0
sbp_send_message(SBP_HEARTBEAT_MSGTYPE, 0x2222, sizeof(hb),
(uint8_t*)&hb);
}
do_every_count++;
}
void GPS_SBP2::update_write(const GPS_Data *d)
{
struct sbp_heartbeat_t {
bool sys_error : 1;
bool io_error : 1;
bool nap_error : 1;
uint8_t res : 5;
uint8_t protocol_minor : 8;
uint8_t protocol_major : 8;
uint8_t res2 : 7;
bool ext_antenna : 1;
} hb; // 4 bytes
struct PACKED sbp_gps_time_t {
uint16_t wn; //< GPS week number
uint32_t tow; //< GPS Time of Week rounded to the nearest ms
int32_t ns; //< Nanosecond remainder of rounded tow
uint8_t flags; //< Status flags (reserved)
} t;
struct PACKED sbp_pos_llh_t {
uint32_t tow; //< GPS Time of Week
double lat; //< Latitude
double lon; //< Longitude
double height; //< Height
uint16_t h_accuracy; //< Horizontal position accuracy estimate
uint16_t v_accuracy; //< Vertical position accuracy estimate
uint8_t n_sats; //< Number of satellites used in solution
uint8_t flags; //< Status flags
} pos;
struct PACKED sbp_vel_ned_t {
uint32_t tow; //< GPS Time of Week
int32_t n; //< Velocity North coordinate
int32_t e; //< Velocity East coordinate
int32_t d; //< Velocity Down coordinate
uint16_t h_accuracy; //< Horizontal velocity accuracy estimate
uint16_t v_accuracy; //< Vertical velocity accuracy estimate
uint8_t n_sats; //< Number of satellites used in solution
uint8_t flags; //< Status flags (reserved)
} velned;
struct PACKED sbp_dops_t {
uint32_t tow; //< GPS Time of Week
uint16_t gdop; //< Geometric Dilution of Precision
uint16_t pdop; //< Position Dilution of Precision
uint16_t tdop; //< Time Dilution of Precision
uint16_t hdop; //< Horizontal Dilution of Precision
uint16_t vdop; //< Vertical Dilution of Precision
uint8_t flags; //< Status flags (reserved)
} dops;
static const uint16_t SBP_HEARTBEAT_MSGTYPE = 0xFFFF;
static const uint16_t SBP_GPS_TIME_MSGTYPE = 0x0102;
static const uint16_t SBP_DOPS_MSGTYPE = 0x0208;
static const uint16_t SBP_POS_LLH_MSGTYPE = 0x020A;
static const uint16_t SBP_VEL_NED_MSGTYPE = 0x020E;
const auto gps_tow = gps_time();
t.wn = gps_tow.week;
t.tow = gps_tow.ms;
t.ns = 0;
t.flags = 1;
sbp_send_message(SBP_GPS_TIME_MSGTYPE, 0x2222, sizeof(t), (uint8_t*)&t);
if (!d->have_lock) {
return;
}
pos.tow = gps_tow.ms;
pos.lon = d->longitude;
pos.lat= d->latitude;
pos.height = d->altitude;
pos.h_accuracy = _sitl->gps_accuracy[instance]*1000;
pos.v_accuracy = _sitl->gps_accuracy[instance]*1000;
pos.n_sats = d->have_lock ? _sitl->gps_numsats[instance] : 3;
// Send single point position solution
pos.flags = 1;
sbp_send_message(SBP_POS_LLH_MSGTYPE, 0x2222, sizeof(pos), (uint8_t*)&pos);
// Send "pseudo-absolute" RTK position solution
pos.flags = 4;
sbp_send_message(SBP_POS_LLH_MSGTYPE, 0x2222, sizeof(pos), (uint8_t*)&pos);
velned.tow = gps_tow.ms;
velned.n = 1e3 * d->speedN;
velned.e = 1e3 * d->speedE;
velned.d = 1e3 * d->speedD;
velned.h_accuracy = 5e3;
velned.v_accuracy = 5e3;
velned.n_sats = d->have_lock ? _sitl->gps_numsats[instance] : 3;
velned.flags = 1;
sbp_send_message(SBP_VEL_NED_MSGTYPE, 0x2222, sizeof(velned), (uint8_t*)&velned);
static uint32_t do_every_count = 0;
if (do_every_count % 5 == 0) {
dops.tow = gps_tow.ms;
dops.gdop = 1;
dops.pdop = 1;
dops.tdop = 1;
dops.hdop = 100;
dops.vdop = 1;
dops.flags = 1;
sbp_send_message(SBP_DOPS_MSGTYPE, 0x2222, sizeof(dops),
(uint8_t*)&dops);
hb.protocol_major = 2; //Sends protocol version 2.0
sbp_send_message(SBP_HEARTBEAT_MSGTYPE, 0x2222, sizeof(hb),
(uint8_t*)&hb);
}
do_every_count++;
}
void GPS_NOVA::update_write(const GPS_Data *d)
{
static struct PACKED nova_header
{
// 0
uint8_t preamble[3];
// 3
uint8_t headerlength;
// 4
uint16_t messageid;
// 6
uint8_t messagetype;
//7
uint8_t portaddr;
//8
uint16_t messagelength;
//10
uint16_t sequence;
//12
uint8_t idletime;
//13
uint8_t timestatus;
//14
uint16_t week;
//16
uint32_t tow;
//20
uint32_t recvstatus;
// 24
uint16_t resv;
//26
uint16_t recvswver;
} header;
struct PACKED psrdop
{
float gdop;
float pdop;
float hdop;
float htdop;
float tdop;
float cutoff;
uint32_t svcount;
// extra data for individual prns
} psrdop {};
struct PACKED bestpos
{
uint32_t solstat;
uint32_t postype;
double lat;
double lng;
double hgt;
float undulation;
uint32_t datumid;
float latsdev;
float lngsdev;
float hgtsdev;
// 4 bytes
uint8_t stnid[4];
float diffage;
float sol_age;
uint8_t svstracked;
uint8_t svsused;
uint8_t svsl1;
uint8_t svsmultfreq;
uint8_t resv;
uint8_t extsolstat;
uint8_t galbeisigmask;
uint8_t gpsglosigmask;
} bestpos {};
struct PACKED bestvel
{
uint32_t solstat;
uint32_t veltype;
float latency;
float age;
double horspd;
double trkgnd;
// + up
double vertspd;
float resv;
} bestvel {};
const auto gps_tow = gps_time();
header.preamble[0] = 0xaa;
header.preamble[1] = 0x44;
header.preamble[2] = 0x12;
header.headerlength = sizeof(header);
header.week = gps_tow.week;
header.tow = gps_tow.ms;
header.messageid = 174;
header.messagelength = sizeof(psrdop);
header.sequence += 1;
psrdop.hdop = 1.20;
psrdop.htdop = 1.20;
nova_send_message((uint8_t*)&header,sizeof(header),(uint8_t*)&psrdop, sizeof(psrdop));
header.messageid = 99;
header.messagelength = sizeof(bestvel);
header.sequence += 1;
bestvel.horspd = norm(d->speedN, d->speedE);
bestvel.trkgnd = ToDeg(atan2f(d->speedE, d->speedN));
bestvel.vertspd = -d->speedD;
nova_send_message((uint8_t*)&header,sizeof(header),(uint8_t*)&bestvel, sizeof(bestvel));
header.messageid = 42;
header.messagelength = sizeof(bestpos);
header.sequence += 1;
bestpos.lat = d->latitude;
bestpos.lng = d->longitude;
bestpos.hgt = d->altitude;
bestpos.svsused = d->have_lock ? _sitl->gps_numsats[instance] : 3;
bestpos.latsdev=0.2;
bestpos.lngsdev=0.2;
bestpos.hgtsdev=0.2;
bestpos.solstat=0;
bestpos.postype=32;
nova_send_message((uint8_t*)&header,sizeof(header),(uint8_t*)&bestpos, sizeof(bestpos));
}
void GPS_NOVA::nova_send_message(uint8_t *header, uint8_t headerlength, uint8_t *payload, uint8_t payloadlen)
{
write_to_autopilot((char*)header, headerlength);
write_to_autopilot((char*)payload, payloadlen);
uint32_t crc = CalculateBlockCRC32(headerlength, header, (uint32_t)0);
crc = CalculateBlockCRC32(payloadlen, payload, crc);
write_to_autopilot((char*)&crc, 4);
}
#define CRC32_POLYNOMIAL 0xEDB88320L
uint32_t GPS_NOVA::CRC32Value(uint32_t icrc)
{
int i;
uint32_t crc = icrc;
for ( i = 8 ; i > 0; i-- )
{
if ( crc & 1 )
crc = ( crc >> 1 ) ^ CRC32_POLYNOMIAL;
else
crc >>= 1;
}
return crc;
}
uint32_t GPS_NOVA::CalculateBlockCRC32(uint32_t length, uint8_t *buffer, uint32_t crc)
{
while ( length-- != 0 )
{
crc = ((crc >> 8) & 0x00FFFFFFL) ^ (CRC32Value(((uint32_t) crc ^ *buffer++) & 0xff));
}
return( crc );
}
void GPS_GSOF::update_write(const GPS_Data *d)
{
// https://receiverhelp.trimble.com/oem-gnss/index.html#GSOFmessages_TIME.html?TocPath=Output%2520Messages%257CGSOF%2520Messages%257C_____25
constexpr uint8_t GSOF_POS_TIME_TYPE { 0x01 };
constexpr uint8_t GSOF_POS_TIME_LEN { 0x0A };
// TODO magic number until SITL supports GPS bootcount based on GPSN_ENABLE
const uint8_t bootcount = 17;
// https://receiverhelp.trimble.com/oem-gnss/GSOFmessages_Flags.html#Position%20flags%201
enum class POS_FLAGS_1 : uint8_t {
NEW_POSITION = 1U << 0,
CLOCK_FIX_CALULATED = 1U << 1,
HORIZ_FROM_THIS_POS = 1U << 2,
HEIGHT_FROM_THIS_POS = 1U << 3,
RESERVED_4 = 1U << 4,
LEAST_SQ_POSITION = 1U << 5,
RESERVED_6 = 1U << 6,
POSITION_L1_PSEUDORANGES = 1U << 7
};
const uint8_t pos_flags_1 {
uint8_t(POS_FLAGS_1::NEW_POSITION) |
uint8_t(POS_FLAGS_1::CLOCK_FIX_CALULATED) |
uint8_t(POS_FLAGS_1::HORIZ_FROM_THIS_POS) |
uint8_t(POS_FLAGS_1::HEIGHT_FROM_THIS_POS) |
uint8_t(POS_FLAGS_1::RESERVED_4) |
uint8_t(POS_FLAGS_1::LEAST_SQ_POSITION) |
uint8_t(POS_FLAGS_1::POSITION_L1_PSEUDORANGES)
};
// https://receiverhelp.trimble.com/oem-gnss/GSOFmessages_Flags.html#Position%20flags%202
enum class POS_FLAGS_2 : uint8_t {
DIFFERENTIAL_POS = 1U << 0,
DIFFERENTIAL_POS_PHASE_RTK = 1U << 1,
POSITION_METHOD_FIXED_PHASE = 1U << 2,
OMNISTAR_ACTIVE = 1U << 3,
DETERMINED_WITH_STATIC_CONSTRAINT = 1U << 4,
NETWORK_RTK = 1U << 5,
DITHERED_RTK = 1U << 6,
BEACON_DGNSS = 1U << 7,
};
// Simulate a GPS without RTK in SIM since there is no RTK SIM params.
// This means these flags are unset:
// NETWORK_RTK, DITHERED_RTK, BEACON_DGNSS
uint8_t pos_flags_2 {0};
if(d->have_lock) {
pos_flags_2 |= uint8_t(POS_FLAGS_2::DIFFERENTIAL_POS);
pos_flags_2 |= uint8_t(POS_FLAGS_2::DIFFERENTIAL_POS_PHASE_RTK);
pos_flags_2 |= uint8_t(POS_FLAGS_2::POSITION_METHOD_FIXED_PHASE);
pos_flags_2 |= uint8_t(POS_FLAGS_2::OMNISTAR_ACTIVE);
pos_flags_2 |= uint8_t(POS_FLAGS_2::DETERMINED_WITH_STATIC_CONSTRAINT);
}
const auto gps_tow = gps_time();
const struct PACKED gsof_pos_time {
const uint8_t OUTPUT_RECORD_TYPE;
const uint8_t RECORD_LEN;
uint32_t time_week_ms;
uint16_t time_week;
uint8_t num_sats;
// https://receiverhelp.trimble.com/oem-gnss/GSOFmessages_Flags.html#Position%20flags%201
uint8_t pos_flags_1;
// https://receiverhelp.trimble.com/oem-gnss/GSOFmessages_Flags.html#Position%20flags%202
uint8_t pos_flags_2;
uint8_t initialized_num;
} pos_time {
GSOF_POS_TIME_TYPE,
GSOF_POS_TIME_LEN,
htobe32(gps_tow.ms),
htobe16(gps_tow.week),
d->have_lock ? _sitl->gps_numsats[instance] : uint8_t(3),
pos_flags_1,
pos_flags_2,
bootcount
};
static_assert(sizeof(gsof_pos_time) - (sizeof(gsof_pos_time::OUTPUT_RECORD_TYPE) + sizeof(gsof_pos_time::RECORD_LEN)) == GSOF_POS_TIME_LEN);
constexpr uint8_t GSOF_POS_TYPE = 0x02;
constexpr uint8_t GSOF_POS_LEN = 0x18;
const struct PACKED gsof_pos {
const uint8_t OUTPUT_RECORD_TYPE;
const uint8_t RECORD_LEN;
uint64_t lat;
uint64_t lng;
uint64_t alt;
} pos {
GSOF_POS_TYPE,
GSOF_POS_LEN,
pack_double_into_gsof_packet(d->latitude * DEG_TO_RAD_DOUBLE),
pack_double_into_gsof_packet(d->longitude * DEG_TO_RAD_DOUBLE),
pack_double_into_gsof_packet(static_cast<double>(d->altitude))
};
static_assert(sizeof(gsof_pos) - (sizeof(gsof_pos::OUTPUT_RECORD_TYPE) + sizeof(gsof_pos::RECORD_LEN)) == GSOF_POS_LEN);
// https://receiverhelp.trimble.com/oem-gnss/GSOFmessages_Velocity.html
constexpr uint8_t GSOF_VEL_TYPE = 0x08;
// use the smaller packet by ignoring local coordinate system
constexpr uint8_t GSOF_VEL_LEN = 0x0D;
// https://receiverhelp.trimble.com/oem-gnss/GSOFmessages_Flags.html#Velocity%20flags
enum class VEL_FIELDS : uint8_t {
VALID = 1U << 0,
CONSECUTIVE_MEASUREMENTS = 1U << 1,
HEADING_VALID = 1U << 2,
RESERVED_3 = 1U << 3,
RESERVED_4 = 1U << 4,
RESERVED_5 = 1U << 5,
RESERVED_6 = 1U << 6,
RESERVED_7 = 1U << 7,
};
uint8_t vel_flags {0};
if(d->have_lock) {
vel_flags |= uint8_t(VEL_FIELDS::VALID);
vel_flags |= uint8_t(VEL_FIELDS::CONSECUTIVE_MEASUREMENTS);
vel_flags |= uint8_t(VEL_FIELDS::HEADING_VALID);
}
const struct PACKED gsof_vel {
const uint8_t OUTPUT_RECORD_TYPE;
const uint8_t RECORD_LEN;
// https://receiverhelp.trimble.com/oem-gnss/GSOFmessages_Flags.html#Velocity%20flags
uint8_t flags;
uint32_t horiz_m_p_s;
uint32_t heading_rad;
uint32_t vertical_m_p_s;
} vel {
GSOF_VEL_TYPE,
GSOF_VEL_LEN,
vel_flags,
pack_float_into_gsof_packet(d->speed_2d()),
pack_float_into_gsof_packet(d->heading()),
// Trimble API has ambiguous direction here.
// Intentionally narrow from double.
pack_float_into_gsof_packet(static_cast<float>(d->speedD))
};
static_assert(sizeof(gsof_vel) - (sizeof(gsof_vel::OUTPUT_RECORD_TYPE) + sizeof(gsof_vel::RECORD_LEN)) == GSOF_VEL_LEN);
// https://receiverhelp.trimble.com/oem-gnss/index.html#GSOFmessages_PDOP.html?TocPath=Output%2520Messages%257CGSOF%2520Messages%257C_____12
constexpr uint8_t GSOF_DOP_TYPE = 0x09;
constexpr uint8_t GSOF_DOP_LEN = 0x10;
const struct PACKED gsof_dop {
const uint8_t OUTPUT_RECORD_TYPE { GSOF_DOP_TYPE };
const uint8_t RECORD_LEN { GSOF_DOP_LEN };
uint32_t pdop = htobe32(1);
uint32_t hdop = htobe32(1);
uint32_t vdop = htobe32(1);
uint32_t tdop = htobe32(1);
} dop {};
// Check the payload size calculation in the compiler
constexpr auto dop_size = sizeof(gsof_dop);
static_assert(dop_size == 18);
constexpr auto dop_record_type_size = sizeof(gsof_dop::OUTPUT_RECORD_TYPE);
static_assert(dop_record_type_size == 1);
constexpr auto len_size = sizeof(gsof_dop::RECORD_LEN);
static_assert(len_size == 1);
constexpr auto dop_payload_size = dop_size - (dop_record_type_size + len_size);
static_assert(dop_payload_size == GSOF_DOP_LEN);
constexpr uint8_t GSOF_POS_SIGMA_TYPE = 0x0C;
constexpr uint8_t GSOF_POS_SIGMA_LEN = 0x26;
const struct PACKED gsof_pos_sigma {
const uint8_t OUTPUT_RECORD_TYPE { GSOF_POS_SIGMA_TYPE };
const uint8_t RECORD_LEN { GSOF_POS_SIGMA_LEN };
uint32_t pos_rms = htobe32(0);
uint32_t sigma_e = htobe32(0);
uint32_t sigma_n = htobe32(0);
uint32_t cov_en = htobe32(0);
uint32_t sigma_up = htobe32(0);
uint32_t semi_major_axis = htobe32(0);
uint32_t semi_minor_axis = htobe32(0);
uint32_t orientation = htobe32(0);
uint32_t unit_variance = htobe32(0);
uint16_t n_epocs = htobe32(1); // Always 1 for kinematic.
} pos_sigma {};
static_assert(sizeof(gsof_pos_sigma) - (sizeof(gsof_pos_sigma::OUTPUT_RECORD_TYPE) + sizeof(gsof_pos_sigma::RECORD_LEN)) == GSOF_POS_SIGMA_LEN);
// TODO add GSOF49
const uint8_t payload_sz = sizeof(pos_time) + sizeof(pos) + sizeof(vel) + sizeof(dop) + sizeof(pos_sigma);
uint8_t buf[payload_sz] = {};
uint8_t offset = 0;
memcpy(&buf[offset], &pos_time, sizeof(pos_time));
offset += sizeof(pos_time);
memcpy(&buf[offset], &pos, sizeof(pos));
offset += sizeof(pos);
memcpy(&buf[offset], &vel, sizeof(vel));
offset += sizeof(vel);
memcpy(&buf[offset], &dop, sizeof(dop));
offset += sizeof(dop);
memcpy(&buf[offset], &pos_sigma, sizeof(pos_sigma));
offset += sizeof(pos_sigma);
assert(offset == payload_sz);
send_gsof(buf, sizeof(buf));
}
void GPS_GSOF::send_gsof(const uint8_t *buf, const uint16_t size)
{
// All Trimble "Data Collector" packets, including GSOF, are comprised of three fields:
// * A fixed-length packet header (dcol_header)
// * A variable-length data frame (buf)
// * A fixed-length packet trailer (dcol_trailer)
// Reference: // https://receiverhelp.trimble.com/oem-gnss/index.html#API_DataCollectorFormatPacketStructure.html?TocPath=API%2520Documentation%257CData%2520collector%2520format%2520packets%257CData%2520collector%2520format%253A%2520packet%2520structure%257C_____0
const uint8_t STX = 0x02;
// status bitfield
// https://receiverhelp.trimble.com/oem-gnss/index.html#API_ReceiverStatusByte.html?TocPath=API%2520Documentation%257CData%2520collector%2520format%2520packets%257CData%2520collector%2520format%253A%2520packet%2520structure%257C_____1
const uint8_t STATUS = 0xa8;
const uint8_t PACKET_TYPE = 0x40; // Report Packet 40h (GENOUT)
// Before writing the GSOF data buffer, the GSOF header needs added between the DCOL header and the payload data frame.
// https://receiverhelp.trimble.com/oem-gnss/index.html#GSOFmessages_GSOF.html?TocPath=Output%2520Messages%257CGSOF%2520Messages%257C_____2
static uint8_t TRANSMISSION_NUMBER = 0; // Functionally, this is a sequence number
// Most messages, even GSOF49, only take one page. For SIM, assume it.
assert(size < 0xFA); // GPS SIM doesn't yet support paging
constexpr uint8_t PAGE_INDEX = 0;
constexpr uint8_t MAX_PAGE_INDEX = 0;
const uint8_t gsof_header[3] = {
TRANSMISSION_NUMBER,
PAGE_INDEX,
MAX_PAGE_INDEX,
};
++TRANSMISSION_NUMBER;
// A captured GSOF49 packet from BD940 has LENGTH field set to 0x6d = 109 bytes.
// A captured GSOF49 packet from BD940 has total bytes of 115 bytes.
// Thus, the following 5 bytes are not counted.
// 1) STX
// 2) STATUS
// 3) PACKET TYPE
// 4) LENGTH
// 5) CHECKSUM
// 6) ETX
// This aligns with manual's idea of data bytes:
// "Each message begins with a 4-byte header, followed by the bytes of data in each packet. The packet ends with a 2-byte trailer."
// Thus, for this implementation with single-page single-record per DCOL packet,
// the length is simply the sum of data packet size, the gsof_header size.
const uint8_t length = size + sizeof(gsof_header);
const uint8_t dcol_header[4] {
STX,
STATUS,
PACKET_TYPE,
length
};
// Sum bytes (status + type + length + data bytes) and modulo 256 the summation
// Because it's a uint8, use natural overflow
uint8_t csum = STATUS + PACKET_TYPE + length;
for (size_t i = 0; i < ARRAY_SIZE(gsof_header); i++) {
csum += gsof_header[i];
}
for (size_t i = 0; i < size; i++) {
csum += buf[i];
}
constexpr uint8_t ETX = 0x03;
const uint8_t dcol_trailer[2] = {
csum,
ETX
};
write_to_autopilot((char*)dcol_header, sizeof(dcol_header));
write_to_autopilot((char*)gsof_header, sizeof(gsof_header));
write_to_autopilot((char*)buf, size);
write_to_autopilot((char*)dcol_trailer, sizeof(dcol_trailer));
const uint8_t total_size = sizeof(dcol_header) + sizeof(gsof_header) + size + sizeof(dcol_trailer);
// Validate length based on everything but DCOL h
if(dcol_header[3] != total_size - (sizeof(dcol_header) + sizeof(dcol_trailer))) {
INTERNAL_ERROR(AP_InternalError::error_t::flow_of_control);
}
}
uint64_t GPS_GSOF::pack_double_into_gsof_packet(const double& src)
{
uint64_t dst;
static_assert(sizeof(src) == sizeof(dst));
memcpy(&dst, &src, sizeof(dst));
dst = htobe64(dst);
return dst;
}
uint32_t GPS_GSOF::pack_float_into_gsof_packet(const float& src)
{
uint32_t dst;
static_assert(sizeof(src) == sizeof(dst));
memcpy(&dst, &src, sizeof(dst));
dst = htobe32(dst);
return dst;
}
/*
send MSP GPS data
*/
void GPS_MSP::update_write(const GPS_Data *d)
{
struct PACKED {
// header
struct PACKED {
uint8_t dollar = '$';
uint8_t magic = 'X';
uint8_t code = '<';
uint8_t flags;
uint16_t cmd = 0x1F03; // GPS
uint16_t size = 52;
} hdr;
uint8_t instance;
uint16_t gps_week;
uint32_t ms_tow;
uint8_t fix_type;
uint8_t satellites_in_view;
uint16_t horizontal_pos_accuracy; // [cm]
uint16_t vertical_pos_accuracy; // [cm]
uint16_t horizontal_vel_accuracy; // [cm/s]
uint16_t hdop;
int32_t longitude;
int32_t latitude;
int32_t msl_altitude; // cm
int32_t ned_vel_north; // cm/s
int32_t ned_vel_east;
int32_t ned_vel_down;
uint16_t ground_course; // deg * 100, 0..36000
uint16_t true_yaw; // deg * 100, values of 0..36000 are valid. 65535 = no data available
uint16_t year;
uint8_t month;
uint8_t day;
uint8_t hour;
uint8_t min;
uint8_t sec;
// footer CRC
uint8_t crc;
} msp_gps {};
auto t = gps_time();
struct timeval tv;
simulation_timeval(&tv);
auto *tm = gmtime(&tv.tv_sec);
msp_gps.gps_week = t.week;
msp_gps.ms_tow = t.ms;
msp_gps.fix_type = d->have_lock?3:0;
msp_gps.satellites_in_view = d->have_lock ? _sitl->gps_numsats[instance] : 3;
msp_gps.horizontal_pos_accuracy = _sitl->gps_accuracy[instance]*100;
msp_gps.vertical_pos_accuracy = _sitl->gps_accuracy[instance]*100;
msp_gps.horizontal_vel_accuracy = 30;
msp_gps.hdop = 100;
msp_gps.longitude = d->longitude * 1.0e7;
msp_gps.latitude = d->latitude * 1.0e7;
msp_gps.msl_altitude = d->altitude * 100;
msp_gps.ned_vel_north = 100 * d->speedN;
msp_gps.ned_vel_east = 100 * d->speedE;
msp_gps.ned_vel_down = 100 * d->speedD;
msp_gps.ground_course = ToDeg(atan2f(d->speedE, d->speedN)) * 100;
msp_gps.true_yaw = wrap_360(d->yaw_deg)*100U; // can send 65535 for no yaw
msp_gps.year = tm->tm_year;
msp_gps.month = tm->tm_mon;
msp_gps.day = tm->tm_mday;
msp_gps.hour = tm->tm_hour;
msp_gps.min = tm->tm_min;
msp_gps.sec = tm->tm_sec;
// CRC is over packet without first 3 bytes and trailing CRC byte
msp_gps.crc = crc8_dvb_s2_update(0, (uint8_t *)&msp_gps.hdr.flags, sizeof(msp_gps)-4);
write_to_autopilot((const char *)&msp_gps, sizeof(msp_gps));
}
/*
read file data logged from AP_GPS_DEBUG_LOGGING_ENABLED
*/
#if AP_SIM_GPS_FILE_ENABLED
void GPS_FILE::update_write(const GPS_Data *d)
{
static int fd[2] = {-1,-1};
static uint32_t base_time[2];
const uint16_t lognum = uint16_t(_sitl->gps_log_num.get());
if (instance > 1) {
return;
}
if (fd[instance] == -1) {
char fname[] = "gpsN_NNN.log";
hal.util->snprintf(fname, 13, "gps%u_%03u.log", instance+1, lognum);
fd[instance] = open(fname, O_RDONLY|O_CLOEXEC);
if (fd[instance] == -1) {
return;
}
}
const uint32_t magic = 0x7fe53b04;
struct {
uint32_t magic;
uint32_t time_ms;
uint32_t n;
} header;
uint8_t *buf = nullptr;
while (true) {
if (::read(fd[instance], (void *)&header, sizeof(header)) != sizeof(header) ||
header.magic != magic) {
goto rewind_file;
}
if (header.time_ms+base_time[instance] > AP_HAL::millis()) {
// not ready for this data yet
::lseek(fd[instance], -sizeof(header), SEEK_CUR);
return;
}
buf = new uint8_t[header.n];
if (buf != nullptr && ::read(fd[instance], buf, header.n) == ssize_t(header.n)) {
write_to_autopilot((const char *)buf, header.n);
delete[] buf;
buf = nullptr;
continue;
}
goto rewind_file;
}
rewind_file:
::printf("GPS[%u] rewind\n", unsigned(instance));
base_time[instance] = AP_HAL::millis();
::lseek(fd[instance], 0, SEEK_SET);
delete[] buf;
}
#endif // AP_SIM_GPS_FILE_ENABLED
void GPS::check_backend_allocation()
{
const Type configured_type = Type(_sitl->gps_type[instance].get());
if (allocated_type == configured_type) {
return;
}
// mismatch; delete any already-allocated backend:
if (backend != nullptr) {
delete backend;
backend = nullptr;
}
// attempt to allocate backend
switch (configured_type) {
case Type::NONE:
// no GPS attached
break;
case Type::UBLOX:
backend = new GPS_UBlox(*this, instance);
break;
case Type::NMEA:
backend = new GPS_NMEA(*this, instance);
break;
case Type::SBP:
backend = new GPS_SBP(*this, instance);
break;
case Type::SBP2:
backend = new GPS_SBP2(*this, instance);
break;
case Type::NOVA:
backend = new GPS_NOVA(*this, instance);
break;
case Type::MSP:
backend = new GPS_MSP(*this, instance);
break;
case Type::GSOF:
backend = new GPS_GSOF(*this, instance);
break;
#if AP_SIM_GPS_FILE_ENABLED
case Type::FILE:
backend = new GPS_FILE(*this, instance);
break;
#endif
};
allocated_type = configured_type;
}
/*
possibly send a new GPS packet
*/
void GPS::update()
{
if (!init_sitl_pointer()) {
return;
}
check_backend_allocation();
if (backend == nullptr) {
return;
}
double latitude =_sitl->state.latitude;
double longitude = _sitl->state.longitude;
float altitude = _sitl->state.altitude;
const double speedN = _sitl->state.speedN;
const double speedE = _sitl->state.speedE;
const double speedD = _sitl->state.speedD;
const uint32_t now_ms = AP_HAL::millis();
if (now_ms < 20000) {
// apply the init offsets for the first 20s. This allows for
// having the origin a long way from the takeoff location,
// which makes testing long flights easier
latitude += _sitl->gps_init_lat_ofs;
longitude += _sitl->gps_init_lon_ofs;
altitude += _sitl->gps_init_alt_ofs;
}
//Capture current position as basestation location for
if (!_gps_has_basestation_position &&
now_ms >= _sitl->gps_lock_time[0]*1000UL) {
_gps_basestation_data.latitude = latitude;
_gps_basestation_data.longitude = longitude;
_gps_basestation_data.altitude = altitude;
_gps_basestation_data.speedN = speedN;
_gps_basestation_data.speedE = speedE;
_gps_basestation_data.speedD = speedD;
_gps_has_basestation_position = true;
}
const uint8_t idx = instance; // alias to avoid code churn
struct GPS_Data d {};
// simulate delayed lock times
bool have_lock = (!_sitl->gps_disable[idx] && now_ms >= _sitl->gps_lock_time[idx]*1000UL);
// run at configured GPS rate (default 5Hz)
if ((now_ms - last_update) < (uint32_t)(1000/_sitl->gps_hertz[idx])) {
return;
}
last_update = now_ms;
d.latitude = latitude;
d.longitude = longitude;
d.yaw_deg = _sitl->state.yawDeg;
d.roll_deg = _sitl->state.rollDeg;
d.pitch_deg = _sitl->state.pitchDeg;
// add an altitude error controlled by a slow sine wave
d.altitude = altitude + _sitl->gps_noise[idx] * sinf(now_ms * 0.0005f) + _sitl->gps_alt_offset[idx];
// Add offset to c.g. velocity to get velocity at antenna and add simulated error
Vector3f velErrorNED = _sitl->gps_vel_err[idx];
d.speedN = speedN + (velErrorNED.x * rand_float());
d.speedE = speedE + (velErrorNED.y * rand_float());
d.speedD = speedD + (velErrorNED.z * rand_float());
d.have_lock = have_lock;
if (_sitl->gps_drift_alt[idx] > 0) {
// add slow altitude drift controlled by a slow sine wave
d.altitude += _sitl->gps_drift_alt[idx]*sinf(now_ms*0.001f*0.02f);
}
// correct the latitude, longitude, height and NED velocity for the offset between
// the vehicle c.g. and GPS antenna
Vector3f posRelOffsetBF = _sitl->gps_pos_offset[idx];
if (!posRelOffsetBF.is_zero()) {
// get a rotation matrix following DCM conventions (body to earth)
Matrix3f rotmat;
_sitl->state.quaternion.rotation_matrix(rotmat);
// rotate the antenna offset into the earth frame
Vector3f posRelOffsetEF = rotmat * posRelOffsetBF;
// Add the offset to the latitude, longitude and height using a spherical earth approximation
double const earth_rad_inv = 1.569612305760477e-7; // use Authalic/Volumetric radius
double lng_scale_factor = earth_rad_inv / cos(radians(d.latitude));
d.latitude += degrees(posRelOffsetEF.x * earth_rad_inv);
d.longitude += degrees(posRelOffsetEF.y * lng_scale_factor);
d.altitude -= posRelOffsetEF.z;
// calculate a velocity offset due to the antenna position offset and body rotation rate
// note: % operator is overloaded for cross product
Vector3f gyro(radians(_sitl->state.rollRate),
radians(_sitl->state.pitchRate),
radians(_sitl->state.yawRate));
Vector3f velRelOffsetBF = gyro % posRelOffsetBF;
// rotate the velocity offset into earth frame and add to the c.g. velocity
Vector3f velRelOffsetEF = rotmat * velRelOffsetBF;
d.speedN += velRelOffsetEF.x;
d.speedE += velRelOffsetEF.y;
d.speedD += velRelOffsetEF.z;
}
// get delayed data
d.timestamp_ms = now_ms;
d = interpolate_data(d, _sitl->gps_delay_ms[instance]);
// Applying GPS glitch
// Using first gps glitch
Vector3f glitch_offsets = _sitl->gps_glitch[idx];
d.latitude += glitch_offsets.x;
d.longitude += glitch_offsets.y;
d.altitude += glitch_offsets.z;
backend->update(d); // i.e. reading configuration etc from autopilot
}
void GPS_Backend::update_read(const GPS_Data *d)
{
// swallow any config bytes
char c;
read_from_autopilot(&c, 1);
}
/*
get delayed data by interpolation
*/
GPS_Data GPS::interpolate_data(const GPS_Data &d, uint32_t delay_ms)
{
const uint8_t N = ARRAY_SIZE(_gps_history);
const uint32_t now_ms = d.timestamp_ms;
// add in into history array, shifting old elements
memmove(&_gps_history[1], &_gps_history[0], sizeof(_gps_history[0])*(ARRAY_SIZE(_gps_history)-1));
_gps_history[0] = d;
for (uint8_t i=0; i<N-1; i++) {
uint32_t dt1 = now_ms - _gps_history[i].timestamp_ms;
uint32_t dt2 = now_ms - _gps_history[i+1].timestamp_ms;
if (delay_ms >= dt1 && delay_ms <= dt2) {
// we will interpolate this pair of samples. Start with
// the older sample
const GPS_Data &s1 = _gps_history[i+1];
const GPS_Data &s2 = _gps_history[i];
GPS_Data d2 = s1;
const float p = (dt2 - delay_ms) / MAX(1,float(dt2 - dt1));
d2.latitude += p * (s2.latitude - s1.latitude);
d2.longitude += p * (s2.longitude - s1.longitude);
d2.altitude += p * (s2.altitude - s1.altitude);
d2.speedN += p * (s2.speedN - s1.speedN);
d2.speedE += p * (s2.speedE - s1.speedE);
d2.speedD += p * (s2.speedD - s1.speedD);
d2.yaw_deg += p * wrap_180(s2.yaw_deg - s1.yaw_deg);
return d2;
}
}
// delay is too long, use last sample
return _gps_history[N-1];
}
float GPS_Data::heading() const
{
const auto velocity = Vector2d{speedE, speedN};
return velocity.angle();
}
float GPS_Data::speed_2d() const
{
const auto velocity = Vector2d{speedN, speedE};
return velocity.length();
}
#endif // HAL_SIM_GPS_ENABLED
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