;------------------------------------------------------------------------------ ;+ ; NAME: fuv_rotation_matrix ; PURPOSE: this procedure prepares the rotation matrix which gives ; the look directions for the IMAGE FUV instruments ; CATEGORY: ; CALLING SEQUENCE: transformation_matrix=fuv_rotation_matrix(omega,theta,$ ; phi,scsv_x,scsv_y,scsv_z,sc_x,sc_y,sc_z,psi) ; ; INPUTS: omega : instrument roll in degrees, fixed in time ; theta : instrument tilt in degrees, fixed in time ; phi : instrument azimuth in degrees ; direction cosines of true spin axis in metal system ; scsv_x = henry's a ; scsv_y = henry's b ; scsv_z = henry's c ; direction cosines of true spin axis in inertial ; GCI system ; sc_x = henry's d ; sc_y = henry's e ; sc_z = henry's f ; psi : phase angle in degrees ; ; OPTIONAL INPUTS: none ; KEYWORD PARAMETERS: none ; OUTPUTS: transformation_matrix ; OPTIONAL OUTPUTS: none ; COMMON BLOCKS: none ; SIDE EFFECTS: none known ; RESTRICTIONS: we here use the "right mathematical" way of preparing ; and using a matrix (IDL ##), not the usual IDL way (#) ; for the moment this looks awful, but provides better ; comparison with C-code ; all input vector components have to describe unit ; vectors and should be given in double precision ; PROCEDURE: ; EXAMPLE: ; SEE ALSO: ; MODIFICATION HISTORY: ; Written by: hfrey, using the mathematics developed by H. Heetderks ; Date: January 4, 2000 ; June 4, 2000 transform all angles into radians ; Written by; rburley, replaced 'stop' statements with return,-1 ; so science data processing is not halted by missing ; or bad data. ; Date: January 9, 2001 ; ;Copyright 1996-2013 United States Government as represented by the ;Administrator of the National Aeronautics and Space Administration. ;All Rights Reserved. ; ;------------------------------------------------------------------ ;- function fuv_rotation_matrix,omega,theta,phi,scsv_x,scsv_y,scsv_z, $ sc_x,sc_y,sc_z,psi ; check the input vectors if (abs(sqrt(scsv_x^2+scsv_y^2+scsv_z^2) - 1.d0) gt 1.d-3) then begin print,'!!!Spacecraft spin vector scsv not unit vector!!!' return,-1 endif if (abs(sqrt(sc_x^2+sc_y^2+sc_z^2) - 1.d0) gt 1.d-3) then begin print,'!!!Spacecraft spin vector sc not unit vector in GCI!!!' return,-1 endif if (sc_x eq 0. and sc_y eq 0. and abs(sc_z) eq 1.) then begin print,'!!!There is no solution for this case!!!' return,-1 endif ; transform angles to radians omegad=omega*!dpi/180d thetad=theta*!dpi/180d phid=phi*!dpi/180d psid = psi*!dpi/180d ; phase angle transform into radians ; T_1 is the transformation from the instrument space with the axis ; x along x-axis of image ; y along y-axis of image ; z pointing into the instrument ; into the spacecraft system with ; z' away from the instrument deck along central metal axis ; x' perpendicular to one side of deck plate ; y' completing right handed system t_1_a = [[cos(omegad),-sin(omegad),0.d], $ [sin(omegad), cos(omegad),0.d], $ [ 0.d, 0.d,1.d]] t_1_b = [[1.d, 0.d, 0.d], $ [0.d,-sin(thetad),-cos(thetad)], $ [0.d, cos(thetad),-sin(thetad)]] t_1_c = [[ sin(phid),cos(phid),0.d], $ [-cos(phid),sin(phid),0.d], $ [ 0.d, 0.d,1.d]] t_1 = t_1_c ## ( t_1_b ## t_1_a) ; T_2 is the transformation from the spacecraft system into the thrue ; spinning system with the axes ; z'' true spin axis ; x'' defined this way that x' lies in x'' - z'' plane ; y'' completing system ; ; input here are direction cosines of true spin axis in spacecraft ; system, they should not change with time once the spacecraft is ; fully deployed ; scsv_x = henry's a ; scsv_y = henry's b ; scsv_z = henry's c sin_alp=scsv_y/sqrt(1.d0-scsv_x^2) cos_alp=scsv_z/sqrt(1.d0-scsv_x^2) sin_bet=scsv_x cos_bet=sqrt(1.d0-scsv_x^2) t_2_a = [[1.d, 0.d, 0.d], $ [0.d,cos_alp,-sin_alp], $ [0.d,sin_alp, cos_alp]] t_2_b = [[cos_bet,0.d,-sin_bet], $ [ 0.d,1.d, 0.d], $ [sin_bet,0.d, cos_bet]] t_2 = t_2_b ## t_2_a ; T_3 is the transformation from the true spinning system into the ; inertial GCI system ; sc_x = henry's d ; sc_y = henry's e ; sc_z = henry's f cos_eta = sc_z/sqrt(1.d0-scsv_x^2) sin_eta = sqrt(1.d0-scsv_x^2-sc_z^2)/sqrt(1.d0-scsv_x^2) cos_del = (scsv_x*sc_x+sc_y*sqrt(1.d0-scsv_x^2-sc_z^2))/(1.d0-sc_z^2) sin_del = (scsv_x*sc_y-sc_x*sqrt(1.d0-scsv_x^2-sc_z^2))/(1.d0-sc_z^2) t_3_a = [[cos(psid),-sin(psid),0.d], $ [sin(psid), cos(psid),0.d], $ [ 0.d, 0.d,1.d]] t_3_b = [[ cos_bet,0.d,sin_bet], $ [ 0.d,1.d, 0.d], $ [-sin_bet,0.d,cos_bet]] t_3_c = [[1.d, 0.d, 0.d], $ [0.d, cos_eta,sin_eta], $ [0.d,-sin_eta,cos_eta]] t_3_d = [[cos_del,-sin_del,0.d], $ [sin_del, cos_del,0.d], $ [ 0.d, 0.d,1.d]] t_3 = t_3_d ## ( t_3_c ## (t_3_b ## t_3_a)) transformation_matrix = t_3 ## (t_2 ## t_1) ;result = transformation_matrix ## [[vector[0]],[vector[1]],[vector[2]]] ;print,'test the transformation' ;print,'Input vector: ',vector[0],vector[1],vector[2] ;print,'transformed vector: ' ;print,result ;stop return,transformation_matrix end