ICD-GPS-870 - GPS.gov

SV Health Six Bit SV Health Word Numerical Representation of Six-Bit
Category in NAV message Health Word in SEM & YUMA Almanac
OTHER 110100 52
OTHER 110101 53
OTHER 110110 54
OTHER 110111 55
OTHER 111000 56
OTHER 111001 57
OTHER 111010 58
OTHER 111011 59
BAD 111100 60
OTHER 111101 61
OTHER 111110 62
DEAD 111111 63
30.4 SEM Almanac Format
The SEM format file example in Figure 30-1 is arranged with a header that identifies the
number of records (number of satellites) and file name (current.al3). The SEM
Almanac sample illustrated below is a data sample of one record out of 28 in this
sample file and its parameter definition, as stated in the note of Figure 30-1, is in Table
30-II. There is an additional SEM file with a file name extension of .bl3 that is identical
to .al3, except for the number of records range, PRN number range and SVN number
field. All parameters are listed in Table 30-III.
32
CURRENT.AL3
Figure 30-1 SEM Data Sample for Current.al3
Note: The bold letters and numbers in the rectangles are not part of the SEM format;
they are used for identification purposes in Table 30-II. Table 30-II identifies the
characteristics of each parameter in the SEM Almanac.
30-3
ICD-GPS-870
15 June 2011