rav2xf_c |

## Procedurevoid rav2xf_c ( ConstSpiceDouble rot [3][3], ConstSpiceDouble av [3], SpiceDouble xform [6][6] ) ## AbstractThis routine determines a state transformation matrix from a rotation matrix and the angular velocity of the rotation. ## Required_ReadingNone. ## KeywordsFRAMES ## Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- rot I Rotation matrix. av I Angular velocity vector. xform O State transformation associated with rot and av. ## Detailed_Inputrot is a rotation that gives the transformation from some frame frame1 to another frame frame2. av is the angular velocity of the transformation. In other words, if p is the position of a fixed point in frame2, then from the point of view of frame1, p rotates (in a right handed sense) about an axis parallel to av. Moreover the rate of rotation in radians per unit time is given by the length of av. More formally, the velocity v of p in frame1 is given by t v = av x ( rot * p ) ## Detailed_Outputxform is a state transformation matrix associated with rot and av. If s1 is the state of an object with respect to frame1, then the state s2 of the object with respect to frame2 is given by s2 = xform * s1 where "*" denotes matrix-vector multiplication. ## ParametersNone. ## ExceptionsError free. 1) No checks are performed on ROT to ensure that it is indeed a rotation matrix. ## FilesNone. ## ParticularsThis routine is essentially a macro routine for converting a rotation and angular velocity of the rotation to the equivalent state transformation matrix. This routine is an inverse of xf2rav_c. ## ExamplesSuppose that you wanted to determine state transformation matrix from a platform frame to the J2000 frame. /. The following call obtains the J2000-to-platform transformation matrix and platform angular velocity at the time of interest. The time value is expressed as encoded SCLK. ./ ckgpav_c ( ckid, time, tol, "J2000", rot, av, &clkout, &fnd ); /. Recall that rot and av are the rotation and angular velocity of the transformation from J2000 to the platform frame. ./ if ( fnd ) { /. First get the state transformation from J2000 to the platform frame. ./ ## RestrictionsNone. ## Literature_ReferencesNone. ## Author_and_InstitutionN.J. Bachman (JPL) W.L. Taber (JPL) ## Version-CSPICE Version 1.0.1, 12-APR-2007 (EDW) Edit to abstract. -CSPICE Version 1.0.0, 18-JUN-1999 (WLT) (NJB) ## Index_EntriesState transformation to rotation and angular velocity |

Wed Apr 5 17:54:41 2017