ardupilot/libraries/AP_Common/Location.cpp

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/*
* Location.cpp
*/
#include "Location.h"
#include <AP_AHRS/AP_AHRS.h>
#include <AP_Terrain/AP_Terrain.h>
extern const AP_HAL::HAL& hal;
AP_Terrain *Location_Class::_terrain = nullptr;
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/// constructors
Location_Class::Location_Class()
{
zero();
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}
Location_Class::Location_Class(int32_t latitude, int32_t longitude, int32_t alt_in_cm, ALT_FRAME frame)
{
lat = latitude;
lng = longitude;
options = 0;
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set_alt_cm(alt_in_cm, frame);
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}
Location_Class::Location_Class(const Location& loc)
{
lat = loc.lat;
lng = loc.lng;
alt = loc.alt;
options = loc.options;
}
Location_Class::Location_Class(const Vector3f &ekf_offset_neu)
{
// store alt and alt frame
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set_alt_cm(ekf_offset_neu.z, ALT_FRAME_ABOVE_ORIGIN);
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// calculate lat, lon
Location ekf_origin;
if (AP::ahrs().get_origin(ekf_origin)) {
lat = ekf_origin.lat;
lng = ekf_origin.lng;
offset(ekf_offset_neu.x / 100.0f, ekf_offset_neu.y / 100.0f);
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}
}
Location_Class& Location_Class::operator=(const struct Location &loc)
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{
lat = loc.lat;
lng = loc.lng;
alt = loc.alt;
options = loc.options;
return *this;
}
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void Location_Class::set_alt_cm(int32_t alt_cm, ALT_FRAME frame)
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{
alt = alt_cm;
flags.relative_alt = false;
flags.terrain_alt = false;
flags.origin_alt = false;
switch (frame) {
case ALT_FRAME_ABSOLUTE:
// do nothing
break;
case ALT_FRAME_ABOVE_HOME:
flags.relative_alt = true;
break;
case ALT_FRAME_ABOVE_ORIGIN:
flags.origin_alt = true;
break;
case ALT_FRAME_ABOVE_TERRAIN:
// we mark it as a relative altitude, as it doesn't have
// home alt added
flags.relative_alt = true;
flags.terrain_alt = true;
break;
}
}
// converts altitude to new frame
bool Location_Class::change_alt_frame(ALT_FRAME desired_frame)
{
int32_t new_alt_cm;
if (!get_alt_cm(desired_frame, new_alt_cm)) {
return false;
}
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set_alt_cm(new_alt_cm, desired_frame);
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return true;
}
// get altitude frame
Location_Class::ALT_FRAME Location_Class::get_alt_frame() const
{
if (flags.terrain_alt) {
return ALT_FRAME_ABOVE_TERRAIN;
}
if (flags.origin_alt) {
return ALT_FRAME_ABOVE_ORIGIN;
}
if (flags.relative_alt) {
return ALT_FRAME_ABOVE_HOME;
}
return ALT_FRAME_ABSOLUTE;
}
/// get altitude in desired frame
bool Location_Class::get_alt_cm(ALT_FRAME desired_frame, int32_t &ret_alt_cm) const
{
Location_Class::ALT_FRAME frame = get_alt_frame();
// shortcut if desired and underlying frame are the same
if (desired_frame == frame) {
ret_alt_cm = alt;
return true;
}
// check for terrain altitude
float alt_terr_cm = 0;
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if (frame == ALT_FRAME_ABOVE_TERRAIN || desired_frame == ALT_FRAME_ABOVE_TERRAIN) {
#if AP_TERRAIN_AVAILABLE
if (_terrain == nullptr || !_terrain->height_amsl(*(Location *)this, alt_terr_cm, true)) {
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return false;
}
// convert terrain alt to cm
alt_terr_cm *= 100.0f;
#else
return false;
#endif
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}
// convert alt to absolute
int32_t alt_abs;
switch (frame) {
case ALT_FRAME_ABSOLUTE:
alt_abs = alt;
break;
case ALT_FRAME_ABOVE_HOME:
if (!AP::ahrs().home_is_set()) {
return false;
}
alt_abs = alt + AP::ahrs().get_home().alt;
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break;
case ALT_FRAME_ABOVE_ORIGIN:
{
// fail if we cannot get ekf origin
Location ekf_origin;
if (!AP::ahrs().get_origin(ekf_origin)) {
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return false;
}
alt_abs = alt + ekf_origin.alt;
}
break;
case ALT_FRAME_ABOVE_TERRAIN:
alt_abs = alt + alt_terr_cm;
break;
default:
// unknown conversion to absolute alt, this should never happen
return false;
}
// convert absolute to desired frame
switch (desired_frame) {
case ALT_FRAME_ABSOLUTE:
ret_alt_cm = alt_abs;
return true;
case ALT_FRAME_ABOVE_HOME:
if (!AP::ahrs().home_is_set()) {
return false;
}
ret_alt_cm = alt_abs - AP::ahrs().get_home().alt;
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return true;
case ALT_FRAME_ABOVE_ORIGIN:
{
// fail if we cannot get ekf origin
Location ekf_origin;
if (!AP::ahrs().get_origin(ekf_origin)) {
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return false;
}
ret_alt_cm = alt_abs - ekf_origin.alt;
return true;
}
case ALT_FRAME_ABOVE_TERRAIN:
ret_alt_cm = alt_abs - alt_terr_cm;
return true;
default:
// should never happen
return false;
}
}
bool Location_Class::get_vector_xy_from_origin_NE(Vector2f &vec_ne) const
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{
Location ekf_origin;
if (!AP::ahrs().get_origin(ekf_origin)) {
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return false;
}
vec_ne.x = (lat-ekf_origin.lat) * LATLON_TO_CM;
vec_ne.y = (lng-ekf_origin.lng) * LATLON_TO_CM * longitude_scale(ekf_origin);
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return true;
}
bool Location_Class::get_vector_from_origin_NEU(Vector3f &vec_neu) const
{
// convert lat, lon
Vector2f vec_ne;
if (!get_vector_xy_from_origin_NE(vec_ne)) {
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return false;
}
vec_neu.x = vec_ne.x;
vec_neu.y = vec_ne.y;
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// convert altitude
int32_t alt_above_origin_cm = 0;
if (!get_alt_cm(ALT_FRAME_ABOVE_ORIGIN, alt_above_origin_cm)) {
return false;
}
vec_neu.z = alt_above_origin_cm;
return true;
}
// return distance in meters between two locations
float Location_Class::get_distance(const struct Location &loc2) const
{
float dlat = (float)(loc2.lat - lat);
float dlng = ((float)(loc2.lng - lng)) * longitude_scale(loc2);
return norm(dlat, dlng) * LOCATION_SCALING_FACTOR;
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}
// extrapolate latitude/longitude given distances (in meters) north and east
void Location_Class::offset(float ofs_north, float ofs_east)
{
// use is_equal() because is_zero() is a local class conflict and is_zero() in AP_Math does not belong to a class
if (!is_equal(ofs_north, 0.0f) || !is_equal(ofs_east, 0.0f)) {
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int32_t dlat = ofs_north * LOCATION_SCALING_FACTOR_INV;
int32_t dlng = (ofs_east * LOCATION_SCALING_FACTOR_INV) / longitude_scale(*this);
lat += dlat;
lng += dlng;
}
}