/**
* \brief Horizontal move of point position
*/
int nmea_move_horz(
const nmeaPOS *start_pos, /**< Start position in radians */
nmeaPOS *end_pos, /**< Result position in radians */
double azimuth, /**< Azimuth (degree) [0, 359] */
double distance /**< Distance (km) */
)
{
nmeaPOS p1 = *start_pos;
int RetVal = 1;
distance /= NMEA_EARTHRADIUS_KM; /* Angular distance covered on earth's surface */
azimuth = nmea_degree2radian(azimuth);
end_pos->lat = asin(
sin(p1.lat) * cos(distance) + cos(p1.lat) * sin(distance) * cos(azimuth));
end_pos->lon = p1.lon + atan2(
sin(azimuth) * sin(distance) * cos(p1.lat), cos(distance) - sin(p1.lat) * sin(end_pos->lat));
if(NMEA_POSIX(isnan)(end_pos->lat) || NMEA_POSIX(isnan)(end_pos->lon))
{
end_pos->lat = 0; end_pos->lon = 0;
RetVal = 0;
}
return RetVal;
}
void nmea_error(const char *str, ...)
{
int size;
va_list arg_list;
char buff[NMEA_DEF_PARSEBUFF];
nmeaErrorFunc func = nmea_property()->error_func;
if(func)
{
va_start(arg_list, str);
size = NMEA_POSIX(vsnprintf)(&buff[0], NMEA_DEF_PARSEBUFF - 1, str, arg_list);
va_end(arg_list);
if(size > 0)
(*func)(&buff[0], size);
}
}
void nmea_error(const char *str, ...)
{
// FILE *file;
// file = fopen("nmeaError.txt","a+");
// fprintf(file,"%s\n",str);
// fclose(file);
int size;
va_list arg_list;
char buff[NMEA_DEF_PARSEBUFF];
nmeaErrorFunc func = nmea_property()->error_func;
if(func)
{
va_start(arg_list, str);
size = NMEA_POSIX(vsnprintf)(&buff[0], NMEA_DEF_PARSEBUFF - 1, str, arg_list);
va_end(arg_list);
if(size > 0)
(*func)(&buff[0], size);
}
}
/**
* \brief Horizontal move of point position
* This function uses an algorithm for an oblate spheroid earth model.
* The algorithm is described here:
* http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf
*/
int nmea_move_horz_ellipsoid(
const nmeaPOS *start_pos, /**< Start position in radians */
nmeaPOS *end_pos, /**< (O) Result position in radians */
double azimuth, /**< Azimuth in radians */
double distance, /**< Distance (km) */
double *end_azimuth /**< (O) Azimuth at end position in radians */
)
{
/* Variables */
double f, a, b, sqr_a, sqr_b;
double phi1, tan_U1, sin_U1, cos_U1, s, alpha1, sin_alpha1, cos_alpha1;
double tan_sigma1, sigma1, sin_alpha, cos_alpha, sqr_cos_alpha, sqr_u, A, B;
double sigma_initial, sigma, sigma_prev, sin_sigma, cos_sigma, cos_2_sigmam, sqr_cos_2_sigmam, delta_sigma;
int remaining_steps;
double tmp1, phi2, lambda, C, L;
/* Check input */
NMEA_ASSERT(start_pos != 0);
NMEA_ASSERT(end_pos != 0);
if (fabs(distance) < 1e-12)
{ /* No move */
*end_pos = *start_pos;
if ( end_azimuth != 0 ) *end_azimuth = azimuth;
return ! (NMEA_POSIX(isnan)(end_pos->lat) || NMEA_POSIX(isnan)(end_pos->lon));
} /* No move */
/* Earth geometry */
f = NMEA_EARTH_FLATTENING;
a = NMEA_EARTH_SEMIMAJORAXIS_M;
b = (1 - f) * a;
sqr_a = a * a;
sqr_b = b * b;
/* Calculation */
phi1 = start_pos->lat;
tan_U1 = (1 - f) * tan(phi1);
cos_U1 = 1 / sqrt(1 + tan_U1 * tan_U1);
sin_U1 = tan_U1 * cos_U1;
s = distance;
alpha1 = azimuth;
sin_alpha1 = sin(alpha1);
cos_alpha1 = cos(alpha1);
tan_sigma1 = tan_U1 / cos_alpha1;
sigma1 = atan2(tan_U1, cos_alpha1);
sin_alpha = cos_U1 * sin_alpha1;
sqr_cos_alpha = 1 - sin_alpha * sin_alpha;
cos_alpha = sqrt(sqr_cos_alpha);
sqr_u = sqr_cos_alpha * (sqr_a - sqr_b) / sqr_b;
A = 1 + sqr_u / 16384 * (4096 + sqr_u * (-768 + sqr_u * (320 - 175 * sqr_u)));
B = sqr_u / 1024 * (256 + sqr_u * (-128 + sqr_u * (74 - 47 * sqr_u)));
/* Initialize iteration */
sigma_initial = s / (b * A);
sigma = sigma_initial;
sin_sigma = sin(sigma);
cos_sigma = cos(sigma);
cos_2_sigmam = cos(2 * sigma1 + sigma);
sqr_cos_2_sigmam = cos_2_sigmam * cos_2_sigmam;
delta_sigma = 0;
sigma_prev = 2 * NMEA_PI;
remaining_steps = 20;
while ((fabs(sigma - sigma_prev) > 1e-12) && (remaining_steps > 0))
{ /* Iterate */
cos_2_sigmam = cos(2 * sigma1 + sigma);
sqr_cos_2_sigmam = cos_2_sigmam * cos_2_sigmam;
sin_sigma = sin(sigma);
cos_sigma = cos(sigma);
delta_sigma = B * sin_sigma * (
cos_2_sigmam + B / 4 * (
cos_sigma * (-1 + 2 * sqr_cos_2_sigmam) -
B / 6 * cos_2_sigmam * (-3 + 4 * sin_sigma * sin_sigma) * (-3 + 4 * sqr_cos_2_sigmam)
));
sigma_prev = sigma;
sigma = sigma_initial + delta_sigma;
remaining_steps --;
} /* Iterate */
/* Calculate result */
tmp1 = (sin_U1 * sin_sigma - cos_U1 * cos_sigma * cos_alpha1);
phi2 = atan2(
sin_U1 * cos_sigma + cos_U1 * sin_sigma * cos_alpha1,
(1 - f) * sqrt(sin_alpha * sin_alpha + tmp1 * tmp1)
);
lambda = atan2(
sin_sigma * sin_alpha1,
cos_U1 * cos_sigma - sin_U1 * sin_sigma * cos_alpha1
);
C = f / 16 * sqr_cos_alpha * (4 + f * (4 - 3 * sqr_cos_alpha));
L = lambda -
(1 - C) * f * sin_alpha * (
sigma + C * sin_sigma *
(cos_2_sigmam + C * cos_sigma * (-1 + 2 * sqr_cos_2_sigmam))
);
/* Result */
end_pos->lon = start_pos->lon + L;
end_pos->lat = phi2;
if ( end_azimuth != 0 )
{
*end_azimuth = atan2(
sin_alpha, -sin_U1 * sin_sigma + cos_U1 * cos_sigma * cos_alpha1
);
}
return ! (NMEA_POSIX(isnan)(end_pos->lat) || NMEA_POSIX(isnan)(end_pos->lon));
}
