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GLAST/LAT > DAQ and FSW > FSW > Doxygen Index > ATT / V1-1-1

Constituent: att     Tag: rad750

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ATT_math.c File Reference

LAT attitude processing mathematical functions. More...

#include "math.h"
#include "ATT/ATT.h"
#include "ATT_private.h"

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Vector Transform Functions
void	ATT_xform_vec_by_quat (double *Ve, const double *Q, const double *Vl)
	Tranform vector coordinates from LAT to J2000.
Quaternion Utility Functions
void	ATT_quat_multiply (double *Qr, const double *Qa, const double *Qb)
	Multiply two quaternions.
double	ATT_quat_magnitude (const double *Q)
	Get a quaternion magnitude.
void	ATT_quat_normalize (double *Q)
	Normallize a quaternion.
void	ATT_quat_conjugate (double *Qr, const double *Qa)
	Get a quaternion conjugate.
Vectory Utility Functions
double	ATT_vec_magnitude (const double *V)
	Get a vector magnitude.
void	ATT_vec_normalize (double *V)
	Normallize a vector.
Functions
void	vector_2_longlat (const double *v, double *longitude, double *latitude)
	Routine to convert cartesian coordinates to longitude-latitude like angular coordinates.
void	ATT_vec_cart_to_sphr_deg (const double *Vc, double *Vs)
	Transform a cartesian vector to spherical (ra,dec) coordinates (degrees).
void	ATT_vec_cart_to_sphr_rad (const double *Vc, double *Vs)
	Transform a cartesian vector to spherical (ra,dec) coordinates (radians).

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Detailed Description

LAT attitude processing mathematical functions.

Author:

D.L. Wood

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Function Documentation

void ATT_quat_conjugate (  double *  Qr, const double *  Qa )

Get a quaternion conjugate. Returns the conjugate of quaternion Qa in Qr. Parameters: Qa  Input quaternion. Qa[0] = q1 (x) Qa[1] = q2 (y) Qa[2] = q3 (z) Qa[3] = q4 (w) Qr  Output conjugate quaternion. Qr[0] = q1 (x) Qr[1] = q2 (y) Qr[2] = q3 (z) Qr[3] = q4 (w)

double ATT_quat_magnitude (  const double *  Q  )

Get a quaternion magnitude. Returns the magnitude of quaternion Q. Parameters: Q  Input quaternion. Q[0] = q1 (x) Q[1] = q2 (y) Q[2] = q3 (z) Q[3] = q4 (w) Returns: The magnitude of Q.

void ATT_quat_multiply (  double *  Qr, const double *  Qa, const double *  Qb )

Multiply two quaternions. Multilplies the quaternion Qa by quaternion Qb and stores the result in Qr. Qr = Qb x Qa. This operation is not commutative. Parameters: Qa  Input quaternion. Qa[0] = q1 (x) Qa[1] = q2 (y) Qa[2] = q3 (z) Qa[3] = q4 (w) Qb  Input quaternion. Qb[0] = q1 (x) Qb[1] = q2 (y) Qb[2] = q3 (z) Qb[3] = q4 (w) Qr  Output quaternion product. Qr[0] = q1 (x) Qr[1] = q2 (y) Qr[2] = q3 (z) Qr[3] = q4 (w)

void ATT_quat_normalize (  double *  Q  )

Normallize a quaternion. Modifies quaternion Q so that the result has magnitude '1'. This function works in place. Parameters: Q  Input quaternion. Q[0] = q1 (x) Q[1] = q2 (y) Q[2] = q3 (z) Q[3] = q4 (w)

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void ATT_vec_cart_to_sphr_deg (  const double *  Vc, double *  Vs )

Transform a cartesian vector to spherical (ra,dec) coordinates (degrees). Transforms the vector Vc in (x,y,z) cartesian coordinates into the vector Vs in (ra,dec) spherical coordinates. Vs is returned in degrees. Parameters: Vc  The input vector in cartisian coordinates. Vc[0] = x Vc[1] = y Vc[2] = z Vs  The output vector in spherical coordinates. Vs[0] = ra Vs[1] = dec

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void ATT_vec_cart_to_sphr_rad (  const double *  Vc, double *  Vs )

Transform a cartesian vector to spherical (ra,dec) coordinates (radians). Transforms the vector Vc in (x,y,z) cartesian coordinates into the vector Vs in (ra,dec) spherical coordinates. Vs is returned in radians. Parameters: Vc  The input vector in cartisian coordinates. Vc[0] = x Vc[1] = y Vc[2] = z Vs  The output vector in spherical coordinates. Vs[0] = ra Vs[1] = dec

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double ATT_vec_magnitude (  const double *  V  )

Get a vector magnitude. Returns the magnitude of vector V. Parameters: V  Input vector. V[0] = x V[1] = y V[2] = z Returns: The magnitude of V.

void ATT_vec_normalize (  double *  V  )

Normallize a vector. Modifies vector V so that the result has magnitude '1'. This function works in place. Parameters: V  Input vector. V[0] = x V[1] = y V[2] = z

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unsigned int ATT_xform_vec_by_quat (  double *  Ve, const double *  Q, const double *  Vl )

Tranform vector coordinates from LAT to J2000. Performs coordinate transformation on the vector Vl, which is assumed to be a cartiesian vector in LAT instrument local coordinates (SC body coordinates). The information in quaternion Q is used to transform the vector coordinates into J2000 (ECI) coordinates. The resulting vector coordinates are stored in Ve. Parameters: Q  Input quaternion. Q[0] = q1 (x) Q[1] = q2 (y) Q[2] = q3 (z) Q[3] = q4 (w) Vl  Input vector in LAT coordinates. Vl[0] = x Vl[1] = y Vl[2] = z Ve  Output vector in J2000 coordinates. Ve[0] = x Ve[1] = y Ve[2] = z

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void vector_2_longlat (  const double *  v, double *  longitude, double *  latitude )  [static]

Routine to convert cartesian coordinates to longitude-latitude like angular coordinates. Adopted from ARGOS/USA ground processing code. Parameters: v  The input vector in cartisian coordinates. Vc[0] = x Vc[1] = y Vc[2] = z longitude  Stores the output "longitude" coordinate. latitude  Stores the output "latitude" coordinate.

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