Attitude and Heading Reference System

Functions and structs for dealing with 'Attitude' and AHRS. More...

Files
file	ahrs.h
	API header file for attitude and AHRS in zscilib.

Data Structures
struct	zsl_attitude
	Represents the orientation of a rigid body with respect to the world frame in terms of roll, pitch and yaw (heading), expressed in degrees. More...

Functions
int	zsl_att_to_vec (struct zsl_attitude *a, struct zsl_vec *v)
	Takes the values in the supplied zsl_attitude, and assigns the same memory address to a zsl_vec, allowing for vector functions to be used on the zsl_attitude values. More...
int	zsl_att_to_euler (struct zsl_attitude *a, struct zsl_euler *e)
	Converts the input zsl_attitude, expessed in degrees, to it's equivalent in radians in the output zsl_euler. More...
int	zsl_att_from_euler (struct zsl_euler *e, struct zsl_attitude *a)
	Converts the input zsl_euler, expessed in radians, to it's equivalent in degrees in the output zsl_attitude. More...
int	zsl_att_from_accelmag (struct zsl_vec *accel, struct zsl_vec *mag, struct zsl_attitude *a)
	Converts a three-axis accelerometer (in m/s^2) and a three-axis magnetometer sample (in micro-Tesla) to attitude. More...
int	zsl_att_from_accel (struct zsl_vec *accel, struct zsl_attitude *a)
	Converts a three-axis accelerometer sample (in m/s^2) to roll and pitch. More...
int	zsl_att_accel_angle (struct zsl_vec *a1, struct zsl_vec *a2, zsl_real_t *b)
	Calculates the angle between two accelerometers. More...

Detailed Description

Functions and structs for dealing with 'Attitude' and AHRS.

Structs like zsl_attitude are inteded to be used as 'last-mile' represetnations, to convert Euler angles (in radians) to something more human-friendly like degrees. Most calculations should make use of Euler angles, and the richer API around them, with conversion to degrees as the final step.

Function Documentation

zsl_att_accel_angle()

int zsl_att_accel_angle	(	struct zsl_vec *	a1,
		struct zsl_vec *	a2,
		zsl_real_t *	b
	)

Calculates the angle between two accelerometers.

Parameters

a1	First acceleration triplet in m/s^2.
a2	First acceleration triplet in m/s^2.
b	Angle between the accelerometers, in radians.

Returns

0 if everything executed correctly, otherwise a negative error code if the accelerometer data is not tridimensional.

zsl_att_from_accel()

int zsl_att_from_accel	(	struct zsl_vec *	accel,
		struct zsl_attitude *	a
	)

Converts a three-axis accelerometer sample (in m/s^2) to roll and pitch.

Parameters

accel	Acceleration triplet in m/s^2.
a	Pointer the the output zsl_attitude struct.

Returns

0 if everything executed correctly, otherwise a negative error code.

zsl_att_from_accelmag()

int zsl_att_from_accelmag	(	struct zsl_vec *	accel,
		struct zsl_vec *	mag,
		struct zsl_attitude *	a
	)

Converts a three-axis accelerometer (in m/s^2) and a three-axis magnetometer sample (in micro-Tesla) to attitude.

Parameters

accel	Acceleration triplet in m/s^2.
mag	Magnetometer triplet in micro-Tesla.
a	Pointer the the output zsl_attitude struct.

Returns

0 if everything executed correctly, otherwise a negative error code.

zsl_att_from_euler()

int zsl_att_from_euler	(	struct zsl_euler *	e,
		struct zsl_attitude *	a
	)

Converts the input zsl_euler, expessed in radians, to it's equivalent in degrees in the output zsl_attitude.

Parameters

e	Pointer to the zsl_euler struct to use.
a	Pointer to the zsl_attitued struct to use.

Returns

0 if everything executed correctly, otherwise a negative error code.

zsl_att_to_euler()

int zsl_att_to_euler	(	struct zsl_attitude *	a,
		struct zsl_euler *	e
	)

Converts the input zsl_attitude, expessed in degrees, to it's equivalent in radians in the output zsl_euler.

Parameters

a	Pointer to the zsl_attitued struct to use.
e	Pointer to the zsl_euler struct to use.

Returns

0 if everything executed correctly, otherwise a negative error code.

zsl_att_to_vec()

int zsl_att_to_vec	(	struct zsl_attitude *	a,
		struct zsl_vec *	v
	)

Takes the values in the supplied zsl_attitude, and assigns the same memory address to a zsl_vec, allowing for vector functions to be used on the zsl_attitude values.

Parameters

a	Pointer to the zsl_attitude struct to use.
v	Pointer to the zsl_vec struct to use.

Returns

0 if everything executed correctly, otherwise a negative error code.