This software demonstrates how to access the ACE ancillary data, which
is distributed in HDF format, in a file called ACE_ANCIL.HDF. You'll also need
HDF routines for your platform, available from http://hdf.ncsa.uiuc.edu/index.html.

ACE_ANCIL.HDF is updated regularly by the ACE Science Center, as new ancillary
data is generated.

The routines which do the work are in ancil_subs.c. They should be enough to
get you started using the data. Check the comments in the code to learn the
limitations.

Definition of the ACE ancillary data structures can be found in
the header files aosr.h and ccr.h, which are in the include directory
of this software package, and in the file README2, also part of this package.

Makefile      You'll need to edit the paths in this file to suit your setup.

NOTE: all the programs below require the full pathname to the file
ACE_ANCIL.HDF file as a commandline input.

The following two programs will be of greatest use to users:
------------------------------------------------------------
get_ACEepoch.c shows how to get ACE Epoch time for a given spacecraft clock.
               ACE Epoch is seconds since Jan 1, 1996. This function uses
	       the clock calibration data to correct for drifts in the
	       spacecraft clock.

get_aosr_struct.c shows how to get the complete set of attitude/orbit data
               for a given spacecraft clock.


The following programs are probably of lesser use:
--------------------------------------------------
ccr_data_rd.c shows how to get an ascii printout of all the clock calibration
              data in an ancillary data file.

aos_data_rd.c shows how to get an ascii printout of all the attitude/orbit
              data in an ancillary data file.
    
get_attitude.c shows how to get RTN attitude for a given spacecraft clock.

get_position.c shows how to get GSE position for a given spacecraft clock.

get_velocity.c shows how to get GSE_velocity for a given spacecraft clock.


------------------------
ancil_subs.c  contains low-level routines for accessing the ancillary data.
              These routines are used in the programs above.

Note: all the routines in ancil_subs.c require the scclock to be passed as
a float64, since some applications require sub-second resolution.