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LibrePilot/flight/libraries/insgps_helper.c

326 lines
10 KiB
C

#include "ins.h"
#include "pios.h"
#include "ahrs_spi_comm.h"
#include "insgps.h"
#include "CoordinateConversions.h"
#define INSGPS_GPS_TIMEOUT 2 /* 2 seconds triggers reinit of position */
#define INSGPS_GPS_MINSAT 6 /* 2 seconds triggers reinit of position */
#define INSGPS_GPS_MINPDOP 3.5 /* minimum PDOP for postition updates */
/* If GPS is more than this distance on any dimension then wait a few updates */
/* and reinitialize there */
#define INSGPS_GPS_FAR 10
// ! Contains the data from the mag sensor chip
extern struct mag_sensor mag_data;
// ! Contains the data from the accelerometer
extern struct accel_sensor accel_data;
// ! Contains the data from the gyro
extern struct gyro_sensor gyro_data;
// ! Conains the current estimate of the attitude
extern struct attitude_solution attitude_data;
// ! Contains data from the altitude sensor
extern struct altitude_sensor altitude_data;
// ! Contains data from the GPS (via the SPI link)
extern struct gps_sensor gps_data;
// ! Offset correction of barometric alt, to match gps data
static float baro_offset = 0;
extern void send_calibration(void);
extern void send_attitude(void);
extern void send_velocity(void);
extern void send_position(void);
extern volatile int8_t ahrs_algorithm;
extern void get_accel_gyro_data();
extern void get_mag_data();
/* INS functions */
/**
* @brief Update the EKF when in outdoor mode. The primary difference is using the GPS values.
*/
uint32_t total_far_count = 0;
uint32_t relocated = 0;
void ins_outdoor_update()
{
static uint32_t ins_last_time;
float gyro[3], accel[3], vel[3];
float dT;
uint16_t sensors;
static uint32_t gps_far_count = 0;
dT = PIOS_DELAY_DiffuS(ins_last_time) / 1e6;
ins_last_time = PIOS_DELAY_GetRaw();
// This should only happen at start up or at mode switches
if (dT > 0.01) {
dT = 0.01;
}
// format data for INS algo
gyro[0] = gyro_data.filtered.x;
gyro[1] = gyro_data.filtered.y;
gyro[2] = gyro_data.filtered.z;
accel[0] = accel_data.filtered.x,
accel[1] = accel_data.filtered.y,
accel[2] = accel_data.filtered.z,
INSStatePrediction(gyro, accel, dT);
attitude_data.quaternion.q1 = Nav.q[0];
attitude_data.quaternion.q2 = Nav.q[1];
attitude_data.quaternion.q3 = Nav.q[2];
attitude_data.quaternion.q4 = Nav.q[3];
send_attitude(); // get message out quickly
INSCovariancePrediction(dT);
PositionActualData positionActual;
PositionActualGet(&positionActual);
positionActual.North = Nav.Pos[0];
positionActual.East = Nav.Pos[1];
positionActual.Down = Nav.Pos[2];
PositionActualSet(&positionActual);
VelocityActualData velocityActual;
VelocityActualGet(&velocityActual);
velocityActual.North = Nav.Vel[0];
velocityActual.East = Nav.Vel[1];
velocityActual.Down = Nav.Vel[2];
VelocityActualSet(&velocityActual);
sensors = 0;
if (gps_data.updated) {
vel[0] = gps_data.groundspeed * cos(gps_data.heading * DEG_TO_RAD);
vel[1] = gps_data.groundspeed * sin(gps_data.heading * DEG_TO_RAD);
vel[2] = 0;
if (abs(gps_data.NED[0] - Nav.Pos[0]) > INSGPS_GPS_FAR ||
abs(gps_data.NED[1] - Nav.Pos[1]) > INSGPS_GPS_FAR ||
abs(gps_data.NED[2] - Nav.Pos[2]) > INSGPS_GPS_FAR ||
abs(vel[0] - Nav.Vel[0]) > INSGPS_GPS_FAR ||
abs(vel[1] - Nav.Vel[1]) > INSGPS_GPS_FAR) {
gps_far_count++;
total_far_count++;
gps_data.updated = false;
if (gps_far_count > 30) {
INSPosVelReset(gps_data.NED, vel);
relocated++;
}
} else {
sensors |= HORIZ_SENSORS | POS_SENSORS;
/*
* When using gps need to make sure that barometer is brought into NED frame
* we should try and see if the altitude from the home location is good enough
* to use for the offset but for now starting with this conservative filter
*/
if (fabs(gps_data.NED[2] + (altitude_data.altitude - baro_offset)) > 10) {
baro_offset = gps_data.NED[2] + altitude_data.altitude;
} else {
/* IIR filter with 100 second or so tau to keep them crudely in the same frame */
baro_offset = baro_offset * 0.999 + (gps_data.NED[2] + altitude_data.altitude) * 0.001;
}
gps_data.updated = false;
}
}
if (mag_data.updated) {
sensors |= MAG_SENSORS;
mag_data.updated = false;
}
if (altitude_data.updated) {
sensors |= BARO_SENSOR;
altitude_data.updated = false;
}
/*
* TODO: Need to add a general sanity check for all the inputs to make sure their kosher
* although probably should occur within INS itself
*/
INSCorrection(mag_data.scaled.axis, gps_data.NED, vel, altitude_data.altitude - baro_offset, sensors);
if (fabs(Nav.gyro_bias[0]) > 0.1 || fabs(Nav.gyro_bias[1]) > 0.1 || fabs(Nav.gyro_bias[2]) > 0.1) {
float zeros[3] = { 0, 0, 0 };
INSSetGyroBias(zeros);
}
}
/**
* @brief Update the EKF when in indoor mode
*/
void ins_indoor_update()
{
static uint32_t updated_without_gps = 0;
float gyro[3], accel[3];
float zeros[3] = { 0, 0, 0 };
static uint32_t ins_last_time = 0;
uint16_t sensors = 0;
float dT;
dT = PIOS_DELAY_DiffuS(ins_last_time) / 1e6;
ins_last_time = PIOS_DELAY_GetRaw();
// This should only happen at start up or at mode switches
if (dT > 0.01) {
dT = 0.01;
}
// format data for INS algo
gyro[0] = gyro_data.filtered.x;
gyro[1] = gyro_data.filtered.y;
gyro[2] = gyro_data.filtered.z;
accel[0] = accel_data.filtered.x,
accel[1] = accel_data.filtered.y,
accel[2] = accel_data.filtered.z,
INSStatePrediction(gyro, accel, dT);
attitude_data.quaternion.q1 = Nav.q[0];
attitude_data.quaternion.q2 = Nav.q[1];
attitude_data.quaternion.q3 = Nav.q[2];
attitude_data.quaternion.q4 = Nav.q[3];
send_attitude(); // get message out quickly
INSCovariancePrediction(dT);
/* Indoors, update with zero position and velocity and high covariance */
sensors = HORIZ_SENSORS | VERT_SENSORS;
if (mag_data.updated && (ahrs_algorithm == INSSETTINGS_ALGORITHM_INSGPS_INDOOR)) {
sensors |= MAG_SENSORS;
mag_data.updated = false;
}
if (altitude_data.updated) {
sensors |= BARO_SENSOR;
altitude_data.updated = false;
}
if (gps_data.updated) {
PositionActualData positionActual;
PositionActualGet(&positionActual);
positionActual.North = gps_data.NED[0];
positionActual.East = gps_data.NED[1];
positionActual.Down = Nav.Pos[2];
PositionActualSet(&positionActual);
VelocityActualData velocityActual;
VelocityActualGet(&velocityActual);
velocityActual.North = gps_data.groundspeed * cos(gps_data.heading * DEG_TO_RAD);
velocityActual.East = gps_data.groundspeed * sin(gps_data.heading * DEG_TO_RAD);
velocityActual.Down = Nav.Vel[2];
VelocityActualSet(&velocityActual);
updated_without_gps = 0;
gps_data.updated = false;
} else {
PositionActualData positionActual;
PositionActualGet(&positionActual);
VelocityActualData velocityActual;
VelocityActualGet(&velocityActual);
positionActual.Down = Nav.Pos[2];
velocityActual.Down = Nav.Vel[2];
if (updated_without_gps > 500) {
// After 2-3 seconds without a GPS update set velocity estimate to NAN
positionActual.North = NAN;
positionActual.East = NAN;
velocityActual.North = NAN;
velocityActual.East = NAN;
} else {
updated_without_gps++;
}
PositionActualSet(&positionActual);
VelocityActualSet(&velocityActual);
}
/*
* TODO: Need to add a general sanity check for all the inputs to make sure their kosher
* although probably should occur within INS itself
*/
INSCorrection(mag_data.scaled.axis, zeros, zeros, altitude_data.altitude, sensors);
if (fabs(Nav.gyro_bias[0]) > 0.1 || fabs(Nav.gyro_bias[1]) > 0.1 || fabs(Nav.gyro_bias[2]) > 0.1) {
float zeros[3] = { 0, 0, 0 };
INSSetGyroBias(zeros);
}
}
/**
* @brief Initialize the EKF assuming stationary
*/
bool inited = false;
float init_q[4];
void ins_init_algorithm()
{
inited = true;
float Rbe[3][3], q[4], accels[3], rpy[3], mag;
float ge[3] = { 0, 0, -9.81 }, zeros[3] = { 0, 0, 0 }, Pdiag[16] = { 25, 25, 25, 5, 5, 5, 1e-5, 1e-5, 1e-5, 1e-5, 1e-5, 1e-5, 1e-5, 1e-4, 1e-4, 1e-4 };
bool using_mags, using_gps;
INSGPSInit();
HomeLocationData home;
HomeLocationGet(&home);
accels[0] = accel_data.filtered.x;
accels[1] = accel_data.filtered.y;
accels[2] = accel_data.filtered.z;
using_mags = (ahrs_algorithm == INSSETTINGS_ALGORITHM_INSGPS_OUTDOOR) || (ahrs_algorithm == INSSETTINGS_ALGORITHM_INSGPS_INDOOR);
using_mags &= (home.Be[0] != 0) || (home.Be[1] != 0) || (home.Be[2] != 0); /* only use mags when valid home location */
using_gps = (ahrs_algorithm == INSSETTINGS_ALGORITHM_INSGPS_OUTDOOR) && (gps_data.quality >= INSGPS_GPS_MINSAT);
/* Block till a data update */
get_accel_gyro_data();
/* Ensure we get mag data in a timely manner */
uint16_t fail_count = 50; // 50 at 200 Hz is up to 0.25 sec
while (using_mags && !mag_data.updated && fail_count--) {
get_mag_data();
get_accel_gyro_data();
AhrsPoll();
PIOS_DELAY_WaituS(2000);
}
using_mags &= mag_data.updated;
if (using_mags) {
RotFrom2Vectors(accels, ge, mag_data.scaled.axis, home.Be, Rbe);
R2Quaternion(Rbe, q);
if (using_gps) {
INSSetState(gps_data.NED, zeros, q, zeros, zeros);
} else {
INSSetState(zeros, zeros, q, zeros, zeros);
}
} else {
// assume yaw = 0
mag = VectorMagnitude(accels);
rpy[1] = asinf(-accels[0] / mag);
rpy[0] = atan2(accels[1] / mag, accels[2] / mag);
rpy[2] = 0;
RPY2Quaternion(rpy, init_q);
if (using_gps) {
INSSetState(gps_data.NED, zeros, init_q, zeros, zeros);
} else {
for (uint32_t i = 0; i < 5; i++) {
INSSetState(zeros, zeros, init_q, zeros, zeros);
ins_indoor_update();
}
}
}
INSResetP(Pdiag);
// TODO: include initial estimate of gyro bias?
}