README FILE <00README_1s.TXT>

San Marco D/L ---- Drag Balance Instrument (DBI) --- 1-s Data

These data were provided by the Italian PI team on several floppy disks
together with this readme file.

The filename convention for the files on these diskettes is as follows:

	nnXXXXmm_pp_dbi_sm_1s.asc

	nn=TA	tape recorded data; 1st measurement period
		    during orbit XXXX
	  =TB	tape recorded data; 2nd measurement period 
	   ..           ....
   	  =TH   tape-recorded data; 7th measurement
	  =TX   all later meas. periods during orbit XXXX
 	  =PS   real-time data

	XXXX= orbit number

	mm=R1   data up to the 1st data gap within a specific measurement
		    period; if there are no data gaps than this is the only file
	  =R2   data from the 1st data gap up to the second data gap
          ...               ....

	pp=D1  files with orbit and instrument status information
      =D2  data files with time and the measured total density

The time in the data files is given relative to the beginning of
the specific measurement period. To get the actual time and date one has to 
retrieve the start time from the corresponding D1 file. Date and time are
given as an integer array IT(6) with six elements (yy,mm,dd,hh,mm,ss).

Orbit parameters can be computed using IT(6) in conjunction with the FORTRAN 
subroutines (ULPAOR, NOI, SGP4, etc and the NORAD orbital elements) provided at
 
https://spdf.gsfc.nasa.gov/pub/documents/old/miscellaneous_documents_from_nssdc/b55111.for .
  
The first call to NOI should be with IFLAG=1 to initialize the program. The 
recommended orbit generator is SGP4 (IEPT=2). Please do not forget to also 
assign the parameter values for the constants in COMMON /CONST/ (REQ=6378.1).

In addition to time and density each data record also includes a
quality mark:
	*	density data lack
	**	noise transition
	***	bias irregular (hole)
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