mirror of https://github.com/ArduPilot/ardupilot
115 lines
3.9 KiB
C++
115 lines
3.9 KiB
C++
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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#include <AP_Common.h>
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#include <AP_Math.h>
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#include <AP_HAL.h>
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#include <AP_Notify.h>
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#include "AP_GPS_Glitch.h"
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extern const AP_HAL::HAL& hal;
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// table of user settable parameters
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const AP_Param::GroupInfo GPS_Glitch::var_info[] PROGMEM = {
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// @Param: ENABLE
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// @DisplayName: GPS Glitch protection enable/disable
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// @Description: Allows you to enable (1) or disable (0) gps glitch protection
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// @Values: 0:Disabled,1:Enabled
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// @User: Standard
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AP_GROUPINFO("ENABLE", 0, GPS_Glitch, _enabled, 1),
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// @Param: RADIUS
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// @DisplayName: GPS glitch protection radius within which all new positions are accepted
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// @Description: GPS glitch protection radius within which all new positions are accepted
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// @Units: cm
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// @Range: 0 5000
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// @Increment: 100
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// @User: Advanced
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AP_GROUPINFO("RADIUS", 1, GPS_Glitch, _radius_cm, GPS_GLITCH_RADIUS_CM),
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// @Param: ACCEL
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// @DisplayName: GPS glitch protection's max vehicle acceleration assumption
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// @Description: GPS glitch protection's max vehicle acceleration assumption
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// @Units: cm/s/s
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// @Range: 0 2000
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// @Increment: 100
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// @User: Advanced
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AP_GROUPINFO("ACCEL", 2, GPS_Glitch, _accel_max_cmss, GPS_GLITCH_ACCEL_MAX_CMSS),
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AP_GROUPEND
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};
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// constuctor
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GPS_Glitch::GPS_Glitch(GPS*& gps) :
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_gps(gps)
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{
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AP_Param::setup_object_defaults(this, var_info);
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}
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// check_position - returns true if gps position is acceptable, false if not
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void GPS_Glitch::check_position()
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{
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uint32_t now = hal.scheduler->millis(); // current system time
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float sane_dt; // time since last sane gps reading
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float accel_based_distance; // movement based on max acceleration
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Location curr_pos; // our current position estimate
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Location gps_pos; // gps reported position
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float distance_cm; // distance from gps to current position estimate in cm
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bool all_ok; // true if the new gps position passes sanity checks
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// exit immediately if we don't have gps lock
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if (_gps == NULL || _gps->status() != GPS::GPS_OK_FIX_3D) {
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_flags.glitching = true;
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return;
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}
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// if not initialised or disabled update last good position and exit
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if (!_flags.initialised || !_enabled) {
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_last_good_update = now;
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_last_good_lat = _gps->latitude;
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_last_good_lon = _gps->longitude;
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_last_good_vel.x = _gps->velocity_north();
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_last_good_vel.y = _gps->velocity_east();
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_flags.initialised = true;
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_flags.glitching = false;
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return;
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}
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// calculate time since last sane gps reading in ms
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sane_dt = (now - _last_good_update) / 1000.0f;
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// project forward our position from last known velocity
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curr_pos.lat = _last_good_lat;
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curr_pos.lng = _last_good_lon;
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location_offset(curr_pos, _last_good_vel.x * sane_dt, _last_good_vel.y * sane_dt);
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// calculate distance from recent gps position to current estimate
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gps_pos.lat = _gps->latitude;
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gps_pos.lng = _gps->longitude;
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distance_cm = get_distance_cm(curr_pos, gps_pos);
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// all ok if within a given hardcoded radius
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if (distance_cm <= _radius_cm) {
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all_ok = true;
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}else{
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// or if within the maximum distance we could have moved based on our acceleration
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accel_based_distance = 0.5f * _accel_max_cmss * sane_dt * sane_dt;
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all_ok = (distance_cm <= accel_based_distance);
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}
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// store updates to gps position
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if (all_ok) {
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// position is acceptable
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_last_good_update = now;
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_last_good_lat = _gps->latitude;
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_last_good_lon = _gps->longitude;
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_last_good_vel.x = _gps->velocity_north();
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_last_good_vel.y = _gps->velocity_east();
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}
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// update glitching flag
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_flags.glitching = !all_ok;
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}
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