// return the number of beacons
uint8_t AP_Beacon::count() const
{
if (!device_ready()) {
return 0;
}
return num_beacons;
}
// return true if sensor is basically healthy (we are receiving data)
bool AP_Beacon::healthy(void)
{
if (!device_ready()) {
return false;
}
return _driver->healthy();
}
// update state. This should be called often from the main loop
void AP_Beacon::update(void)
{
if (!device_ready()) {
return;
}
_driver->update();
}
// return beacon position in meters
Vector3f AP_Beacon::beacon_position(uint8_t beacon_instance) const
{
if (!device_ready() || beacon_instance >= num_beacons) {
Vector3f temp = {};
return temp;
}
return beacon_state[beacon_instance].position;
}
// return all beacon data
bool AP_Beacon::get_beacon_data(uint8_t beacon_instance, struct BeaconState& state) const
{
if (!device_ready() || beacon_instance >= num_beacons) {
return false;
}
state = beacon_state[beacon_instance];
return true;
}
// return fence boundary array
const Vector2f* AP_Beacon::get_boundary_points(uint16_t& num_points) const
{
if (!device_ready()) {
num_points = 0;
return nullptr;
}
num_points = boundary_num_points;
return boundary;
}
// update state. This should be called often from the main loop
void AP_Beacon::update(void)
{
if (!device_ready()) {
return;
}
_driver->update();
// update boundary for fence
update_boundary_points();
}
// return position in NED from position estimate system's origin in meters
bool AP_Beacon::get_vehicle_position_ned(Vector3f &position, float& accuracy_estimate) const
{
if (!device_ready()) {
return false;
}
// check for timeout
if (AP_HAL::millis() - veh_pos_update_ms > AP_BEACON_TIMEOUT_MS) {
return false;
}
// return position
position = veh_pos_ned;
accuracy_estimate = veh_pos_accuracy;
return true;
}
// return origin of position estimate system
bool AP_Beacon::get_origin(Location &origin_loc) const
{
if (!device_ready()) {
return false;
}
// check for un-initialised origin
if (is_zero(origin_lat) && is_zero(origin_lon) && is_zero(origin_alt)) {
return false;
}
// return origin
origin_loc = {};
origin_loc.lat = origin_lat * 1.0e7f;
origin_loc.lng = origin_lon * 1.0e7f;
origin_loc.alt = origin_alt * 100;
return true;
}
// return origin of position estimate system
bool AP_Beacon::get_origin(Location &origin_loc) const
{
if (!device_ready()) {
return false;
}
// check for un-initialised origin
if (is_zero(origin_lat) && is_zero(origin_lon) && is_zero(origin_alt)) {
return false;
}
// return origin
origin_loc.lat = origin_lat * 1.0e7;
origin_loc.lng = origin_lon * 1.0e7;
origin_loc.alt = origin_alt * 100;
origin_loc.options = 0; // all flags to zero meaning alt-above-sea-level
return true;
}
int device_alloc(struct device **device, const char *path)
{
struct device *dev;
int r;
if (!path) {
*device = NULL;
return 0;
}
dev = malloc(sizeof(struct device));
if (!dev)
return -ENOMEM;
memset(dev, 0, sizeof(struct device));
dev->loop_fd = -1;
r = device_ready(path);
if (!r) {
dev->init_done = 1;
} else if (r == -ENOTBLK) {
/* alloc loop later */
} else if (r < 0) {
free(dev);
return -ENOTBLK;
}
dev->path = strdup(path);
if (!dev->path) {
free(dev);
return -ENOMEM;
}
*device = dev;
return 0;
}
// create fence boundary points
void AP_Beacon::update_boundary_points()
{
// we need three beacons at least to create boundary fence.
// update boundary fence if number of beacons changes
if (!device_ready() || num_beacons < AP_BEACON_MINIMUM_FENCE_BEACONS || boundary_num_beacons == num_beacons) {
return;
}
// record number of beacons so we do not repeat calculations
boundary_num_beacons = num_beacons;
// accumulate beacon points
Vector2f beacon_points[AP_BEACON_MAX_BEACONS];
for (uint8_t index = 0; index < num_beacons; index++) {
const Vector3f& point_3d = beacon_position(index);
beacon_points[index].x = point_3d.x;
beacon_points[index].y = point_3d.y;
}
// create polygon around boundary points using the following algorithm
// set the "current point" as the first boundary point
// loop through all the boundary points looking for the point which creates a vector (from the current point to this new point) with the lowest angle
// check if point is already in boundary
// - no: add to boundary, move current point to this new point and repeat the above
// - yes: we've completed the bounding box, delete any boundary points found earlier than the duplicate
Vector2f boundary_points[AP_BEACON_MAX_BEACONS+1]; // array of boundary points
uint8_t curr_boundary_idx = 0; // index into boundary_sorted index. always points to the highest filled in element of the array
uint8_t curr_beacon_idx = 0; // index into beacon_point array. point indexed is same point as curr_boundary_idx's
// initialise first point of boundary_sorted with first beacon's position (this point may be removed later if it is found to not be on the outer boundary)
boundary_points[curr_boundary_idx] = beacon_points[curr_beacon_idx];
bool boundary_success = false; // true once the boundary has been successfully found
bool boundary_failure = false; // true if we fail to build the boundary
float start_angle = 0.0f; // starting angle used when searching for next boundary point, on each iteration this climbs but never climbs past PI * 2
while (!boundary_success && !boundary_failure) {
// look for next outer point
uint8_t next_idx;
float next_angle;
if (get_next_boundary_point(beacon_points, num_beacons, curr_beacon_idx, start_angle, next_idx, next_angle)) {
// add boundary point to boundary_sorted array
curr_boundary_idx++;
boundary_points[curr_boundary_idx] = beacon_points[next_idx];
curr_beacon_idx = next_idx;
start_angle = next_angle;
// check if we have a complete boundary by looking for duplicate points within the boundary_sorted
uint8_t dup_idx = 0;
bool dup_found = false;
while (dup_idx < curr_boundary_idx && !dup_found) {
dup_found = (boundary_points[dup_idx] == boundary_points[curr_boundary_idx]);
if (!dup_found) {
dup_idx++;
}
}
// if duplicate is found, remove all boundary points before the duplicate because they are inner points
if (dup_found) {
uint8_t num_pts = curr_boundary_idx - dup_idx + 1;
if (num_pts > AP_BEACON_MINIMUM_FENCE_BEACONS) {
// success, copy boundary points to boundary array and convert meters to cm
for (uint8_t j = 0; j < num_pts; j++) {
boundary[j] = boundary_points[j+dup_idx] * 100.0f;
}
boundary_num_points = num_pts;
boundary_success = true;
} else {
// boundary has too few points
boundary_failure = true;
}
}
} else {
// failed to create boundary - give up!
boundary_failure = true;
}
}
// clear boundary on failure
if (boundary_failure) {
boundary_num_points = 0;
}
}
