GLONASS

The data are placed in files called

Older data file (1994-2002) of satellite health status you can find here: health_a.glo

Organization of status.glo file: The content of this file is in development. At present this file contains just numbers of launched satellites, changes in their configuration, and inserting or removing of the satellite from the almanac. We are going to keep this file up to date.

Organization of satellite health drop-outs file: In the file health.glo is a list of detected satellite drop-outs indicated in the almanac .

Organization of almanac data: We provide satellite almanac data as received from GLONASS satellites. You should find the almanac in almanac.glo file. Every data item is proceeded by a variable name. Variable name conventions: all names were chosen so that they would match the symbols used in the Interface Control Document. Most of the variables contain a subscript. Each subscript is separated from a variable name by a slash (”/”). Greek symbols are rewritten following their pronunciation and they are distinguished from other letters of a variable name by underscore (“_”). The value and the name of a variable are split by equal sign (”=”).

The file consists of two parts:

  1. Header
  2. Satellites data
 *****  1) HEADER  *****

The almanac  file begins with two lines.  The first line  contains date and
time when almanac was received and the second line contains variable T/c.
 
T/c      System time offset (to UTC-SU)

Example:

ALMANAC was received on  14 Jan 1994, 14:42:24 UTC-SU

T/c           = -0.00001628


ALMANAC was received on  24 Nov 1993, 22:51:28 UTC-SU

T/c           = -0.00001559



 *****  2) SATELLITES DATA  *****

Satellite data begin with a keyword "ALM:". Satellites are distinguished
from each other by an empty line.

N               Current day in the four year period (and a readable form of date) units [days]; range (1..1461)
n               Satellite number       range (1, 24)
H/n             Frequency number       range (1..24)
lambda/n        Longitude of ascending node       units [semi cycle]; range (+-1)
t/lambda_n      Ascending node passing time       units [s]; range (0, 44100)
i/n             Inclination       units [semi cycle]; range (0.35 +-0,067)
T/n             Revolving period       units [s]; range (43200 +-3600)
DELTA_T_DOT/n   Time change of period       [s/orbit]
epsilon/n       Eccentricity       [dimensionless]; range (0, 0.03)
omega/n         Perigee argument       units [semi cycle]; range (+-1)
tau/n           Satellite time offset (to system time)       units [s]; range (+-1.9ms)
C/n             State of satellite with an explanation (GOOD, BAD) behind       [dimensionless]; values (0, 1)

Example:

ALM:


N             =  744   ( 13 Jan 1994 )
n             =  1
H/n           =  23
lambda/n      = -2.98002243041992E-0001
t/lambda_n    =  24137.96875
i/n           =  3.60543823242187E-0001
T/n           =  4.05441582031250E+0004
DELTA_T_DOT/n = -6.10351562500000E-0005
epsilon/n     =  6.56127929687500E-0004
omega/n       = -9.80529785156250E-0001
tau/n         =  1.18255615234375E-0004
C/n           =  1   (GOOD)


N             =  744   ( 13 Jan 1994 )
n             =  2
H/n           =  5
lambda/n      = -4.13681030273438E-0001
t/lambda_n    =  29088.43750
i/n           =  3.60583877563477E-0001
T/n           =  4.05440605468750E+0004
DELTA_T_DOT/n = -6.10351562500000E-0005

...etc.
 
 
almanacs/glonass.txt · Last modified: 2010/11/24 15:11 by webadmin
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