attid1.for is a FORTRAN subroutine for attitude processing
attid2.c  is a C version


stucture of attitude data files
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1. Data are arranged in the files, with filenames  corresponding 
   to telemetry sessions sequence.

2. Data format is ASCII.

3. Format of a first line in a file (FORTRAN format specifications):
   1X,I2 - number in a sequence in the file (0)
   1X,A2 - code of a satellite (AZ, TZ... )
   1X,A1 - type of telemetry (S/C - SSNI/STO ) 
   1X,I1 - telemetry session (1/2 - direct/memory)
   1X,I5 - number of a session (YYDDD)
   1X,I1 - number of a part of session
   1X,I4,1X,I2,1X,I2,1X,F7.3 - YYYY MM DD TS - beginning of a session, UT  
   1X,I4,1X,I2,1X,I2,1X,F7.3 - YYYY MM DD TS - end of a session, UT  

   Note: TS - thousands of seconds in a day

4. Format of data structures
   1X,I2 - number in a sequence in the file (1...)
   1X,I4,1X,I2,1X,I2,1X,F7.3 - YYYY MM DD TS - beginning of an interval, UT  
   1X,F7.3 - TS - duration of an interval  
   14(1X,F) - X[12], Z[2] - initial data for attitude determination 

   Note: TS - thousands of seconds in a day


subroutine input and output parameters
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TS  - time in thousands of sec relative to beginning of the interval 
      (negative values supported).

U1,U2  - direction in the S/C frame of reference, degrees (input)
         U1 - angle between vector and X S/C axis (polar angle)
         U2 - angle in the YZ S/C plane (anticlockwise)

dir(1..2..3) - corresponding unit vector in the GSE frame (output)   

X,Z - arrays with the initial data set.