cspice_xf2eul |
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## AbstractCSPICE_XF2EUL converts a state transformation matrix to Euler angles and their derivatives with respect to a specified set of axes. The companion routine cspice_eul2xf converts Euler angles and their derivatives with respect to a specified set of axes to a state transformation matrix. ## I/OGiven: xform operator(s) that transform state vector(s) from some frame "frame1" to another frame "frame2." [6,6] = size(xform); double = class(xform) or [6,6,n] = size(xform); double = class(xform) axisa axisb axisc the axes desired for the factorization of "r". All must be in the range from 1 to 3. Moreover it must be the case that 'axisa' and 'axisb' are distinct and that 'axisb' and 'axisc' are distinct. [1,1] = size(axisa); int32 = class(axisa) [1,1] = size(axisb); int32 = class(axisb) [1,1] = size(axisc); int32 = class(axisc) Every rotation matrix can be represented as a product of three rotation matrices about the principal axes of a reference frame. r = [ alpha ] [ beta ] [ gamma ] axisa axisb axisc The value 1 corresponds to the X axis. The value 2 corresponds to the Y axis. The value 3 corresponds to the Z axis. the call: [eulang, unique] = ## ExamplesAny numerical results shown for this example may differ between platforms as the results depend on the SPICE kernels used as input and the machine specific arithmetic implementation. Use the meta-kernel shown below to load the required SPICE kernels. KPL/MK This meta-kernel is intended to support operation of SPICE example programs. The kernels shown here should not be assumed to contain adequate or correct versions of data required by SPICE-based user applications. In order for an application to use this meta-kernel, the kernels referenced here must be present in the user's current working directory. The names and contents of the kernels referenced by this meta-kernel are as follows: File name Contents --------- -------- de421.bsp Planetary ephemeris pck00009.tpc Planet orientation and radii naif0009.tls Leapseconds \begindata KERNELS_TO_LOAD = ( '/kernels/gen/lsk/naif0009.tls' '/kernels/gen/spk/de421.bsp' '/kernels/gen/pck/pck00009.tpc' ) \begintext % % Load the SPK, PCK and LSK kernels. % cspice_furnsh( 'standard.tm' ) % % Suppose that you wish to determine the rate of change of % the right ascension and declination of the pole of the moon, % from the state transformation matrix that transforms J2000 % states to object fixed states. % % Using this routine with the routine cspice_sxform_c you can determine % these instantaneous rates. % % Recall that the rotation component of 'tsipm' is given by % % [w] [halfpi_c-dec] [ra+halfpi_c] % 3 1 3 % % Define the number of ephemeris times to perform the calculation. % N = 100; % % Calculate the separation of each ephemeris time, in seconds, % over an eighteen year span. % STEP = 18 * 365 * cspice_spd/N; % % Base the ephemeris time set at May 15, 2007. % et = [0:N]*STEP + cspice_str2et( 'May 15, 2007' ); % % Calculate the state transformation matrices corresponding % to 'et', then convert those matrices to Euler angles (3-1-3). % tsipm = cspice_sxform( 'J2000', 'IAU_MOON', et ); [ eulang, unique ] = ## ParticularsThis function is intended to provide an inverse for the function cspice_eul2xf. ## Required ReadingFor important details concerning this module's function, please refer to the CSPICE routine xf2eul_c. MICE.REQ ## Version-Mice Version 1.2.1, 19-SEP-2016, EDW (JPL) Corrected usage string typo, 'xform' should show dimension as (6,6). Edited I/O section to conform to NAIF standard for Mice documentation. -Mice Version 1.2.0, 10-MAY-2011, EDW (JPL) "logical" call replaced with "zzmice_logical." -Mice Version 1.0.1, 06-MAY-2009, EDW (JPL) Added MICE.REQ reference to the Required Reading section. -Mice Version 1.0.0, 02-APR-2007, EDW (JPL) ## Index_EntriesEuler angles and derivatives from state transformation |

Wed Apr 5 18:00:36 2017