diff options
Diffstat (limited to 'apps/systemlib/geo/geo.c')
-rw-r--r-- | apps/systemlib/geo/geo.c | 120 |
1 files changed, 69 insertions, 51 deletions
diff --git a/apps/systemlib/geo/geo.c b/apps/systemlib/geo/geo.c index bc467bfa3..789368fbd 100644 --- a/apps/systemlib/geo/geo.c +++ b/apps/systemlib/geo/geo.c @@ -89,7 +89,7 @@ __EXPORT float get_bearing_to_next_waypoint(double lat_now, double lon_now, doub __EXPORT crosstrack_error_s get_distance_to_line(double lat_now, double lon_now, double lat_start, double lon_start, double lat_end, double lon_end) { // This function returns the distance to the nearest point on the track line. Distance is positive if current -// position is right of the track and negative if left of the track as seen from a point on the track line +// position is right of the track and negative if left of the track as seen from a point on the track line // headed towards the end point. crosstrack_error_s return_var; @@ -97,43 +97,46 @@ __EXPORT crosstrack_error_s get_distance_to_line(double lat_now, double lon_now, float bearing_end; float bearing_track; float bearing_diff; - + return_var.error = true; // Set error flag, cleared when valid result calculated. return_var.past_end = false; return_var.distance = 0.0f; return_var.bearing = 0.0f; - + // Return error if arguments are bad - if(lat_now == 0.0d || lon_now == 0.0d || lat_start == 0.0d || lon_start == 0.0d || lat_end == 0.0d || lon_end == 0.0d) return return_var; - + if (lat_now == 0.0d || lon_now == 0.0d || lat_start == 0.0d || lon_start == 0.0d || lat_end == 0.0d || lon_end == 0.0d) return return_var; + bearing_end = get_bearing_to_next_waypoint(lat_now, lon_now, lat_end, lon_end); bearing_track = get_bearing_to_next_waypoint(lat_start, lon_start, lat_end, lon_end); bearing_diff = bearing_track - bearing_end; bearing_diff = _wrapPI(bearing_diff); - + // Return past_end = true if past end point of line - if(bearing_diff > M_PI_2_F || bearing_diff < -M_PI_2_F) { + if (bearing_diff > M_PI_2_F || bearing_diff < -M_PI_2_F) { return_var.past_end = true; return_var.error = false; return return_var; } - + dist_to_end = get_distance_to_next_waypoint(lat_now, lon_now, lat_end, lon_end); - return_var.distance = (dist_to_end)*sin(bearing_diff); - if(sin(bearing_diff) >=0 ) { + return_var.distance = (dist_to_end) * sin(bearing_diff); + + if (sin(bearing_diff) >= 0) { return_var.bearing = _wrapPI(bearing_track - M_PI_2_F); + } else { return_var.bearing = _wrapPI(bearing_track + M_PI_2_F); } + return_var.error = false; - + return return_var; } -__EXPORT crosstrack_error_s get_distance_to_arc(double lat_now, double lon_now, double lat_center, double lon_center, - float radius, float arc_start_bearing, float arc_sweep) +__EXPORT crosstrack_error_s get_distance_to_arc(double lat_now, double lon_now, double lat_center, double lon_center, + float radius, float arc_start_bearing, float arc_sweep) { // This function returns the distance to the nearest point on the track arc. Distance is positive if current // position is right of the arc and negative if left of the arc as seen from the closest point on the arc and @@ -146,68 +149,76 @@ __EXPORT crosstrack_error_s get_distance_to_arc(double lat_now, double lon_now, float bearing_sector_end; float bearing_now = get_bearing_to_next_waypoint(lat_now, lon_now, lat_center, lon_center); bool in_sector; - + return_var.error = true; // Set error flag, cleared when valid result calculated. return_var.past_end = false; return_var.distance = 0.0f; return_var.bearing = 0.0f; - + // Return error if arguments are bad - if(lat_now == 0.0d || lon_now == 0.0d || lat_center == 0.0d || lon_center == 0.0d || radius == 0.0d) return return_var; - - - if(arc_sweep >= 0) { + if (lat_now == 0.0d || lon_now == 0.0d || lat_center == 0.0d || lon_center == 0.0d || radius == 0.0d) return return_var; + + + if (arc_sweep >= 0) { bearing_sector_start = arc_start_bearing; bearing_sector_end = arc_start_bearing + arc_sweep; - if(bearing_sector_end > 2.0f*M_PI_F) bearing_sector_end -= M_TWOPI_F; + + if (bearing_sector_end > 2.0f * M_PI_F) bearing_sector_end -= M_TWOPI_F; + } else { bearing_sector_end = arc_start_bearing; bearing_sector_start = arc_start_bearing - arc_sweep; - if(bearing_sector_start < 0.0) bearing_sector_start += M_TWOPI_F; + + if (bearing_sector_start < 0.0) bearing_sector_start += M_TWOPI_F; } + in_sector = false; - + // Case where sector does not span zero - if(bearing_sector_end >= bearing_sector_start && bearing_now >= bearing_sector_start && bearing_now <= bearing_sector_end) in_sector = true; - + if (bearing_sector_end >= bearing_sector_start && bearing_now >= bearing_sector_start && bearing_now <= bearing_sector_end) in_sector = true; + // Case where sector does span zero - if(bearing_sector_end < bearing_sector_start && ( bearing_now > bearing_sector_start || bearing_now < bearing_sector_end ) ) in_sector = true; - + if (bearing_sector_end < bearing_sector_start && (bearing_now > bearing_sector_start || bearing_now < bearing_sector_end)) in_sector = true; + // If in the sector then calculate distance and bearing to closest point - if(in_sector) { + if (in_sector) { return_var.past_end = false; float dist_to_center = get_distance_to_next_waypoint(lat_now, lon_now, lat_center, lon_center); - - if(dist_to_center <= radius) { + + if (dist_to_center <= radius) { return_var.distance = radius - dist_to_center; return_var.bearing = bearing_now + M_PI_F; + } else { return_var.distance = dist_to_center - radius; return_var.bearing = bearing_now; } - - // If out of the sector then calculate dist and bearing to start or end point + + // If out of the sector then calculate dist and bearing to start or end point + } else { - - // Use the approximation that 111,111 meters in the y direction is 1 degree (of latitude) - // and 111,111 * cos(latitude) meters in the x direction is 1 degree (of longitude) to - // calculate the position of the start and end points. We should not be doing this often - // as this function generally will not be called repeatedly when we are out of the sector. - - // TO DO - this is messed up and won't compile + + // Use the approximation that 111,111 meters in the y direction is 1 degree (of latitude) + // and 111,111 * cos(latitude) meters in the x direction is 1 degree (of longitude) to + // calculate the position of the start and end points. We should not be doing this often + // as this function generally will not be called repeatedly when we are out of the sector. + + // TO DO - this is messed up and won't compile float start_disp_x = radius * sin(arc_start_bearing); float start_disp_y = radius * cos(arc_start_bearing); - float end_disp_x = radius * sin(_wrapPI(arc_start_bearing+arc_sweep)); - float end_disp_y = radius * cos(_wrapPI(arc_start_bearing+arc_sweep)); - float lon_start = lon_now + start_disp_x/111111.0d; - float lat_start = lat_now + start_disp_y*cos(lat_now)/111111.0d; - float lon_end = lon_now + end_disp_x/111111.0d; - float lat_end = lat_now + end_disp_y*cos(lat_now)/111111.0d; + float end_disp_x = radius * sin(_wrapPI(arc_start_bearing + arc_sweep)); + float end_disp_y = radius * cos(_wrapPI(arc_start_bearing + arc_sweep)); + float lon_start = lon_now + start_disp_x / 111111.0d; + float lat_start = lat_now + start_disp_y * cos(lat_now) / 111111.0d; + float lon_end = lon_now + end_disp_x / 111111.0d; + float lat_end = lat_now + end_disp_y * cos(lat_now) / 111111.0d; float dist_to_start = get_distance_to_next_waypoint(lat_now, lon_now, lat_start, lon_start); float dist_to_end = get_distance_to_next_waypoint(lat_now, lon_now, lat_end, lon_end); - if(dist_to_start < dist_to_end) { + + if (dist_to_start < dist_to_end) { return_var.distance = dist_to_start; return_var.bearing = get_bearing_to_next_waypoint(lat_now, lon_now, lat_start, lon_start); + } else { return_var.past_end = true; return_var.distance = dist_to_end; @@ -215,10 +226,10 @@ __EXPORT crosstrack_error_s get_distance_to_arc(double lat_now, double lon_now, } } - + return_var.bearing = _wrapPI(return_var.bearing); return_var.error = false; - return return_var; + return return_var; } float _wrapPI(float bearing) @@ -227,21 +238,25 @@ float _wrapPI(float bearing) while (bearing > M_PI_F) { bearing = bearing - M_TWOPI_F; } + while (bearing <= -M_PI_F) { bearing = bearing + M_TWOPI_F; } + return bearing; } - + float _wrap2PI(float bearing) { while (bearing >= M_TWOPI_F) { bearing = bearing - M_TWOPI_F; } + while (bearing < 0.0f) { bearing = bearing + M_TWOPI_F; } + return bearing; } @@ -251,23 +266,26 @@ float _wrap180(float bearing) while (bearing > 180.0f) { bearing = bearing - 360.0f; } + while (bearing <= -180.0f) { bearing = bearing + 360.0f; } + return bearing; } - + float _wrap360(float bearing) { while (bearing >= 360.0f) { bearing = bearing - 360.0f; } + while (bearing < 0.0f) { bearing = bearing + 360.0f; } + return bearing; } - -
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