ardupilot/libraries/AP_InertialSensor/AP_InertialSensor_SITL.cpp

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/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
#include <AP_HAL/AP_HAL.h>
#include "AP_InertialSensor_SITL.h"
#include <SITL/SITL.h>
#if CONFIG_HAL_BOARD == HAL_BOARD_SITL
const extern AP_HAL::HAL& hal;
AP_InertialSensor_SITL::AP_InertialSensor_SITL(AP_InertialSensor &imu) :
AP_InertialSensor_Backend(imu)
{
}
/*
detect the sensor
*/
AP_InertialSensor_Backend *AP_InertialSensor_SITL::detect(AP_InertialSensor &_imu)
{
AP_InertialSensor_SITL *sensor = new AP_InertialSensor_SITL(_imu);
if (sensor == NULL) {
return NULL;
}
if (!sensor->init_sensor()) {
delete sensor;
return NULL;
}
return sensor;
}
bool AP_InertialSensor_SITL::init_sensor(void)
{
sitl = (SITL::SITL *)AP_Param::find_object("SIM_");
if (sitl == nullptr) {
return false;
}
// grab the used instances
for (uint8_t i=0; i<INS_SITL_INSTANCES; i++) {
gyro_instance[i] = _imu.register_gyro(sitl->update_rate_hz);
accel_instance[i] = _imu.register_accel(sitl->update_rate_hz);
}
hal.scheduler->register_timer_process(FUNCTOR_BIND_MEMBER(&AP_InertialSensor_SITL::timer_update, void));
_product_id = AP_PRODUCT_ID_NONE;
return true;
}
void AP_InertialSensor_SITL::timer_update(void)
{
// minimum noise levels are 2 bits, but averaged over many
// samples, giving around 0.01 m/s/s
float accel_noise = 0.01f;
float accel2_noise = 0.01f;
// minimum gyro noise is also less than 1 bit
float gyro_noise = ToRad(0.04f);
if (sitl->motors_on) {
// add extra noise when the motors are on
accel_noise += sitl->accel_noise;
accel2_noise += sitl->accel2_noise;
gyro_noise += ToRad(sitl->gyro_noise);
}
// get accel bias (add only to first accelerometer)
Vector3f accel_bias = sitl->accel_bias.get();
float xAccel1 = sitl->state.xAccel + accel_noise * rand_float() + accel_bias.x;
float yAccel1 = sitl->state.yAccel + accel_noise * rand_float() + accel_bias.y;
float zAccel1 = sitl->state.zAccel + accel_noise * rand_float() + accel_bias.z;
float xAccel2 = sitl->state.xAccel + accel2_noise * rand_float();
float yAccel2 = sitl->state.yAccel + accel2_noise * rand_float();
float zAccel2 = sitl->state.zAccel + accel2_noise * rand_float();
if (fabsf(sitl->accel_fail) > 1.0e-6f) {
xAccel1 = sitl->accel_fail;
yAccel1 = sitl->accel_fail;
zAccel1 = sitl->accel_fail;
}
Vector3f accel0 = Vector3f(xAccel1, yAccel1, zAccel1) + _imu.get_accel_offsets(0);
Vector3f accel1 = Vector3f(xAccel2, yAccel2, zAccel2) + _imu.get_accel_offsets(1);
_notify_new_accel_raw_sample(accel_instance[0], accel0);
_notify_new_accel_raw_sample(accel_instance[1], accel1);
float p = radians(sitl->state.rollRate) + gyro_drift();
float q = radians(sitl->state.pitchRate) + gyro_drift();
float r = radians(sitl->state.yawRate) + gyro_drift();
float p1 = p + gyro_noise * rand_float();
float q1 = q + gyro_noise * rand_float();
float r1 = r + gyro_noise * rand_float();
float p2 = p + gyro_noise * rand_float();
float q2 = q + gyro_noise * rand_float();
float r2 = r + gyro_noise * rand_float();
Vector3f gyro0 = Vector3f(p1, q1, r1) + _imu.get_gyro_offsets(0);
Vector3f gyro1 = Vector3f(p2, q2, r2) + _imu.get_gyro_offsets(1);
// add in gyro scaling
Vector3f scale = sitl->gyro_scale;
gyro0.x *= (1 + scale.x*0.01);
gyro0.y *= (1 + scale.y*0.01);
gyro0.z *= (1 + scale.z*0.01);
gyro1.x *= (1 + scale.x*0.01);
gyro1.y *= (1 + scale.y*0.01);
gyro1.z *= (1 + scale.z*0.01);
_notify_new_gyro_raw_sample(gyro_instance[0], gyro0);
_notify_new_gyro_raw_sample(gyro_instance[1], gyro1);
}
// generate a random float between -1 and 1
float AP_InertialSensor_SITL::rand_float(void)
{
return ((((unsigned)random()) % 2000000) - 1.0e6) / 1.0e6;
}
float AP_InertialSensor_SITL::gyro_drift(void)
{
if (sitl->drift_speed == 0.0f ||
sitl->drift_time == 0.0f) {
return 0;
}
double period = sitl->drift_time * 2;
double minutes = fmod(AP_HAL::micros64() / 60.0e6, period);
if (minutes < period/2) {
return minutes * ToRad(sitl->drift_speed);
}
return (period - minutes) * ToRad(sitl->drift_speed);
}
bool AP_InertialSensor_SITL::update(void)
{
for (uint8_t i=0; i<INS_SITL_INSTANCES; i++) {
update_accel(accel_instance[i]);
update_gyro(gyro_instance[i]);
}
return true;
}
#endif // HAL_BOARD_SITL