Paparazzi UAS  v5.15_devel-112-g521f3cf
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ekf_range.h File Reference
#include "std.h"
#include "math/pprz_algebra_float.h"
#include "math/pprz_geodetic_float.h"
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Go to the source code of this file.

Data Structures

struct  EKFRange
 EKF_range structure. More...
 

Macros

#define EKF_RANGE_DIM   6
 

Functions

void ekf_range_init (struct EKFRange *ekf_range, float P0_pos, float P0_speed, float Q_sigma2, float R_dist, float R_speed, float dt)
 Init EKF_range internal struct. More...
 
void ekf_range_set_state (struct EKFRange *ekf_range, struct EnuCoor_f pos, struct EnuCoor_f speed)
 Set initial state vector. More...
 
void ekf_range_get_state (struct EKFRange *ekf_range, struct EnuCoor_f *pos, struct EnuCoor_f *speed)
 Get current state. More...
 
struct EnuCoor_f ekf_range_get_pos (struct EKFRange *ekf_range)
 Get current pos. More...
 
struct EnuCoor_f ekf_range_get_speed (struct EKFRange *ekf_range)
 Get current speed. More...
 
void ekf_range_update_noise (struct EKFRange *ekf_range, float Q_sigma2, float R_dist, float R_speed)
 Update process and measurement noises. More...
 
void ekf_range_predict (struct EKFRange *ekf_range)
 Prediction step. More...
 
void ekf_range_update_dist (struct EKFRange *ekf_range, float dist, struct EnuCoor_f anchor)
 Update step based on each new distance data. More...
 
void ekf_range_update_speed (struct EKFRange *ekf_range, float speed, uint8_t type)
 Update step based on speed measure. More...
 

Detailed Description

Author
Gautier Hattenberger EKF based on range measurements algorithm

Definition in file ekf_range.h.


Data Structure Documentation

struct EKFRange

EKF_range structure.

state vector: X = [ x xd y yd z zd ]' command vector: U = 0 (constant velocity model) dynamic model: basic kinematic model x_k+1 = x_k + xd_k * dt measures: distance between (fixed and known) anchors and UAV

Definition at line 43 of file ekf_range.h.

Data Fields
float dt prediction step (in seconds)
float P[EKF_RANGE_DIM][EKF_RANGE_DIM] covariance matrix
float Q[EKF_RANGE_DIM][EKF_RANGE_DIM] process noise matrix
float R_dist measurement noise on distances (assumed the same for all anchors)
float R_speed measurement noise on speed (assumed the same for all axis)
float state[EKF_RANGE_DIM] state vector

Macro Definition Documentation

#define EKF_RANGE_DIM   6

Definition at line 33 of file ekf_range.h.

Referenced by ekf_range_init(), ekf_range_predict(), and ekf_range_update_noise().

Function Documentation

struct EnuCoor_f ekf_range_get_pos ( struct EKFRange ekf_range)

Get current pos.

Parameters
[in]ekf_rangeEKFRange structure
Returns
current position

Definition at line 75 of file ekf_range.c.

References EnuCoor_f::x, EnuCoor_f::y, and EnuCoor_f::z.

Referenced by check_and_compute_data(), and dw1000_arduino_periodic().

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struct EnuCoor_f ekf_range_get_speed ( struct EKFRange ekf_range)

Get current speed.

Parameters
[in]ekf_rangeEKFRange structure
Returns
current speed

Definition at line 84 of file ekf_range.c.

References EnuCoor_f::x, EnuCoor_f::y, and EnuCoor_f::z.

Referenced by check_and_compute_data(), and dw1000_arduino_periodic().

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void ekf_range_get_state ( struct EKFRange ekf_range,
struct EnuCoor_f pos,
struct EnuCoor_f speed 
)

Get current state.

Parameters
[in]ekf_rangeEKFRange structure
[out]poscurrent position
[out]speedcurrent speed

Definition at line 65 of file ekf_range.c.

References EKFRange::state, EnuCoor_f::x, EnuCoor_f::y, and EnuCoor_f::z.

void ekf_range_init ( struct EKFRange ekf_range,
float  P0_pos,
float  P0_speed,
float  Q_sigma2,
float  R_dist,
float  R_speed,
float  dt 
)

Init EKF_range internal struct.

Parameters
[in]ekf_rangeEKFRange structure
[in]P0_posinitial covariance on position
[in]P0_speedinitial covariance on speed
[in]Q_sigma2process noise
[in]R_distmeasurement noise on distance
[in]R_speedmeasurement noise on speed
[in]dtprediction time step in seconds

Definition at line 29 of file ekf_range.c.

References EKFRange::dt, EKF_RANGE_DIM, EKFRange::P, EKFRange::Q, EKFRange::R_dist, EKFRange::R_speed, and EKFRange::state.

Referenced by dw1000_arduino_init().

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void ekf_range_predict ( struct EKFRange ekf_range)

Prediction step.

Parameters
[in]ekf_rangeEKFRange structure

Prediction step.

F = [ 1 dt 0 0 0 0 0 1 0 0 0 0 0 0 1 dt 0 0 0 0 0 1 0 0 0 0 0 0 1 dt 0 0 0 0 0 1 ]

Definition at line 119 of file ekf_range.c.

References EKFRange::dt, EKF_RANGE_DIM, EKFRange::P, EKFRange::Q, and EKFRange::state.

Referenced by dw1000_arduino_periodic().

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void ekf_range_set_state ( struct EKFRange ekf_range,
struct EnuCoor_f  pos,
struct EnuCoor_f  speed 
)

Set initial state vector.

This function should be called after initialization of the ekf struct and before running the filter for better results and faster convergence

Parameters
[in]ekf_rangeEKFRange structure
[in]posinitial position
[in]speedinitial speed

Definition at line 55 of file ekf_range.c.

References EKFRange::state, EnuCoor_f::x, EnuCoor_f::y, and EnuCoor_f::z.

Referenced by check_and_compute_data().

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void ekf_range_update_dist ( struct EKFRange ekf_range,
float  dist,
struct EnuCoor_f  anchor 
)

Update step based on each new distance data.

Parameters
[in]ekf_rangeEKFRange structure
[in]distnew distance measurement
[in]anchorposition of the anchor from which the distance is measured

Update step based on each new distance data.

K = PHt(HPHt+R)^1 X = X + K(z-h(X)) P = (I-KH)P

Definition at line 143 of file ekf_range.c.

References K, EKFRange::P, EKFRange::R_dist, EKFRange::state, EnuCoor_f::x, EnuCoor_f::y, and EnuCoor_f::z.

Referenced by check_and_compute_data().

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void ekf_range_update_noise ( struct EKFRange ekf_range,
float  Q_sigma2,
float  R_dist,
float  R_speed 
)

Update process and measurement noises.

Parameters
[in]ekf_rangeEKFRange structure
[in]Q_sigma2process noise
[in]R_distmeasurement noise on distance
[in]R_speedmeasurement noise on speed

Definition at line 93 of file ekf_range.c.

References EKFRange::dt, EKF_RANGE_DIM, EKFRange::Q, EKFRange::R_dist, and EKFRange::R_speed.

Referenced by dw1000_arduino_update_ekf_q(), dw1000_arduino_update_ekf_r_dist(), and dw1000_arduino_update_ekf_r_speed().

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void ekf_range_update_speed ( struct EKFRange ekf_range,
float  speed,
uint8_t  type 
)

Update step based on speed measure.

Parameters
[in]ekf_rangeEKFRange structure
[in]speednew speed measurement
[in]type1: horizontal ground speed norm, 2: vertical ground speed norm, 3: 3D ground speed norm

Definition at line 191 of file ekf_range.c.