The Harris-Priester Drag file (harris_priester_density_tables.dat) provides the data file for 1964 Harris–Priester Atmospheric density modeling. This model bases the density profile on a specified flux level for the radiation at the 10.7 cm wavelength. A table of integral flux values (measured at F10.7 = 65, 75, 100, 125, 150, 175, 200, 225, 250, 275 x10-22 W/m2/Hz) provides the atmospheric density for altitudes between 110 and 2000 kilometers. The data file also provides constant density values below 110 km.
Note: This file is not time dependent. It is not updated with each FreeFlyer release.
Below is a semi log plot showing the atmospheric density changes as a function of altitude when using the Harris Priester model. The data for this plot was generated in FreeFlyer for the density profile on Jul 01 2012 00:00:00.000.
Plot of the atmospheric density as a function of altitude from 110 km to 2000 km. The data used for the plot was taken directly from the atmosden.dat file included with FreeFlyer.
References:
1."Goddard Trajectory Determination System (GTDS) Mathematical Theory", FDD/552-89/001 and CSC/TR-89/6001, July 1989 |
Harris Priester Drag File Format
The format of the Harris Priester Drag file included with FreeFlyer installation is shown below.
Harris-Priester Atmospheric Density Models File Layout
Logical Record Size = 1680 , Block size = 1680 , 9 blocks -------------------------------------------------------------- Bytes | Desciption -------------------------------------------------------------- 1-1440 | DENSTY(I,J) I=1,3 ; J= 1,60 | Atmospheric Density Table | I=1 : Altitude (km) | I=2 : Minimum density (kg/km3) | I=3 : Maximum density (km/km3) 1441-1512 | DESCR(I) I=1,10 | Description of model 1513-1516 | MODNBR: Model number 1517-1520 | NDENS: # of altitude entries in density table (upper bound of J subscript) 1521-1524 | NBRATM: Largest record number in use on file 1525-1528 | MAXATM: Maximum number of models permitted (=10) 1529-1536 | YMDHMS: Date of last maintenance performed 1537-1540 | IFLAG: Last maintenance operation indicator | =1, initialize | =2, add | =3, modify | =4, delete 1541-1680 | Spares -------------------------------------------------------------
File Summary Report of Contents
MODEL NUMBER: 1 NUMBER OF ENTRIES IN DENSITY ARRAY: 59 MODEL NAME: 1964 HARRIS/PRIESTER ATMOSPHERE (MIN-MAX) 0-2000 KM F=65
MODEL NUMBER: 2 NUMBER OF ENTRIES IN DENSITY ARRAY: 59 MODEL NAME: 1964 HARRIS/PRIESTER ATMOSPHERE (MIN-MAX) 0-2000 KM F=75
MODEL NUMBER: 3 NUMBER OF ENTRIES IN DENSITY ARRAY: 59 MODEL NAME: 1964 HARRIS/PRIESTER ATMOSPHERE (MIN-MAX) 0-2000 KM F=100
MODEL NUMBER: 4 NUMBER OF ENTRIES IN DENSITY ARRAY: 59 MODEL NAME: 1964 HARRIS/PRIESTER ATMOSPHERE (MIN-MAX) 0-2000 KM F=125
MODEL NUMBER: 5 NUMBER OF ENTRIES IN DENSITY ARRAY: 59 MODEL NAME: 1964 HARRIS/PRIESTER ATMOSPHERE (MIN-MAX) 0-2000 KM F=150
MODEL NUMBER: 6 NUMBER OF ENTRIES IN DENSITY ARRAY: 59 MODEL NAME: 1964 HARRIS/PRIESTER ATMOSPHERE (MIN-MAX) 0-2000 KM F=175
MODEL NUMBER: 7 NUMBER OF ENTRIES IN DENSITY ARRAY: 59 MODEL NAME: 1964 HARRIS/PRIESTER ATMOSPHERE (MIN-MAX) 0-2000 KM F=200
MODEL NUMBER: 8 NUMBER OF ENTRIES IN DENSITY ARRAY: 59 MODEL NAME: 1964 HARRIS/PRIESTER ATMOSPHERE (MIN-MAX) 0-2000 KM F=225
MODEL NUMBER: 9 NUMBER OF ENTRIES IN DENSITY ARRAY: 59 MODEL NAME: 1964 HARRIS/PRIESTER ATMOSPHERE (MIN-MAX) 0-2000 KM F=250
MODEL NUMBER: 10 NUMBER OF ENTRIES IN DENSITY ARRAY: 59 MODEL NAME: 1964 HARRIS/PRIESTER ATMOSPHERE (MIN-MAX) 0-2000 KM F=275 |