ardupilot/libraries/AP_Baro/AP_Baro_Glitch.cpp

122 lines
3.9 KiB
C++
Raw Normal View History

// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
#include <AP_Common.h>
#include <AP_Math.h>
#include <AP_HAL.h>
#include <AP_Notify.h>
#include "AP_Baro_Glitch.h"
extern const AP_HAL::HAL& hal;
// table of user settable parameters
const AP_Param::GroupInfo Baro_Glitch::var_info[] PROGMEM = {
// @Param: ENABLE
// @DisplayName: Baro Glitch protection enable/disable
// @Description: Allows you to enable (1) or disable (0) baro glitch protection
// @Values: 0:Disabled,1:Enabled
// @User: Standard
AP_GROUPINFO("ENABLE", 0, Baro_Glitch, _enabled, 1),
// @Param: DIST
// @DisplayName: Baro glitch protection distance within which alt update is immediately accepted
// @Description: Baro glitch protection distance within which alt update is immediately accepted
// @Units: cm
// @Range: 100 2000
// @Increment: 100
// @User: Advanced
AP_GROUPINFO("DIST", 1, Baro_Glitch, _dist_ok_cm, BARO_GLITCH_DISTANCE_OK_CM),
// @Param: ACCEL
// @DisplayName: Baro glitch protection's max vehicle acceleration assumption
// @Description: Baro glitch protection's max vehicle acceleration assumption
// @Units: cm/s/s
// @Range: 100 2000
// @Increment: 100
// @User: Advanced
AP_GROUPINFO("ACCEL", 2, Baro_Glitch, _accel_max_cmss, BARO_GLITCH_ACCEL_MAX_CMSS),
AP_GROUPEND
};
// constuctor
Baro_Glitch::Baro_Glitch(AP_Baro &baro) :
_baro(baro),
_last_good_update(0),
_last_good_alt(0),
_last_good_vel(0.0f)
{
AP_Param::setup_object_defaults(this, var_info);
// initialise flags
_flags.initialised = 0;
_flags.glitching = 0;
}
// check_alt - checks latest baro altitude against last know alt, velocity and maximum acceleration and updates glitching flag
void Baro_Glitch::check_alt()
{
uint32_t now = hal.scheduler->millis(); // current system time
float sane_dt; // time since last sane baro reading
float accel_based_distance; // movement based on max acceleration
int32_t alt_projected; // altitude estimate projected from previous iteration
int32_t distance_cm; // distance from baro alt to current alt estimate in cm
bool all_ok; // true if the new baro alt passes sanity checks
// exit immediately if baro is unhealthy
2014-08-13 10:53:35 -03:00
if (!_baro.healthy()) {
_flags.glitching = true;
return;
}
// if not initialised or disabled update last good alt and exit
if (!_flags.initialised || !_enabled) {
_last_good_update = now;
_last_good_alt = _baro.get_altitude();
_last_good_vel = _baro.get_climb_rate();
_flags.initialised = true;
_flags.glitching = false;
return;
}
// calculate time since last sane baro reading in ms
sane_dt = (now - _last_good_update) / 1000.0f;
// estimate our alt from last known alt and velocity
alt_projected = _last_good_alt + (_last_good_vel * sane_dt);
// calculate distance from recent baro alt to current estimate
int32_t baro_alt = _baro.get_altitude() * 100.0f;
// baro may have become unhealthy when calculating altitude
if (!_baro.healthy()) {
_flags.glitching = true;
return;
}
// calculte distance from projected distance
distance_cm = labs(alt_projected - baro_alt);
// all ok if within a given hardcoded radius
if (distance_cm <= _dist_ok_cm) {
all_ok = true;
}else{
// or if within the maximum distance we could have moved based on our acceleration
accel_based_distance = 0.5f * _accel_max_cmss * sane_dt * sane_dt;
all_ok = (distance_cm <= accel_based_distance);
}
// store updates to baro position
if (all_ok) {
// position is acceptable
_last_good_update = now;
_last_good_alt = baro_alt;
_last_good_vel = _baro.get_climb_rate();
}
// update glitching flag
_flags.glitching = !all_ok;
}