nav_eq.h File Reference

Header file for the OpenShoe navigation algorithm. More...

#include "nav_types.h"
#include <math.h>
#include <stdint.h>
#include "compiler.h"

Go to the source code of this file.

Defines
#define	MAX_ORIENTATIONS   12
	Maximum numbers of orientations that can be used in the accelerometer calibration.
#define	MIN_ORIENTATIONS   3
	Minimum numbers of orientations that can be used in the accelerometer calibration.
#define	MATRIX_INVERSION_ERROR   1
	Value returned in the error message if an error occurred in the matrix inversion.
#define	ACC_STATIONARITY_ERROR   2
	Value returned in the error message if the IMU was not stationary during the accelerometer calibration.
#define	ACC_CALIBRATION_ILLCONDITIONED   3
	Value returned in the error message if the orientations used in the accelerometer calibration were poorly chosen.
#define	NUMBER_OF_ORIENTATIONS_TO_LARGE   4
	Value returned in the error message if the number of orientations specified for the accelerometer calibration is to large. It has been changed to 12.
#define	NUMBER_OF_ORIENTATIONS_TO_SMALL   5
	Value returned in the error message if the number of orientations specified for the accelerometer calibration is to few. It has been changed to 3.
#define	absf(a)   (a>0 ? a:-a)
	Absolute value of a floating point variable.
Functions
void	calibrate_accelerometers (void)
	Function for calibrating the accelerometer biases.
void	estimate_accelerometer_biases (void)
	Function that estimates the accelerometer biases given a matrix of the mean of the measured acceleration at different orientations.
void	correct_navigation_states (void)
	Function for correcting the navigation states given a zero-velocity detection.
void	gain_matrix (void)
	Function for calculating the Kalman filter gain matrix.
void	initialize_navigation_algorithm (void)
	Function for initializing the navigation algorithm.
void	measurement_update (void)
	Function for doing a measurement update of the Kalman filter covariance.
void	strapdown_mechanisation_equations (void)
	Function for doing a time update of the mechanized navigation equations.
void	time_up_data (void)
	Function for doing a time update of the Kalman filter state covariance.
void	update_imu_data_buffers (void)
	Function that updates the IMU data buffers with the latest values read from the IMU, and writes the IMU data to that should be process at the current iteration to the processing variables.
void	ZUPT_detector (void)
	Function for detecting when the system has zero-velocity.
void	zupt_update (void)
	Wrapper function that checks if a zero-velocity update should be done, and then calls all navigation algorithm functions that should be executed during a zero-velocity update.

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Detailed Description

Header file for the OpenShoe navigation algorithm.

This is the header file for the OpenShoe navigation algorithm. It includes the function declarations for all the signal processing functions needed to implement a zero-velocity aided inertial navigation system using a nine state Kalman filter working in a complimentary feedback configuration. It also includes function declarations for the functions needed to implement a accelerometer bias calibration framework.

Authors:

John-Olof Nilsson, Isaac Skog

Copyright:

Copyright (c) 2011 OpenShoe, ISC License (open source)