2-01
DGP000814AAA
GSS6100 and SimCHAN user manual
© Spirent Communications Plc 2005 - 2007
H-13
SBAS Correction Data Files
H.1.2.12 Message Type 18: Ionospheric Grid Mask
There are nine grid mask bands (0 to 8) each defining the status of 201 grid
points (200 for band 8), so nine messages would be required to transmit all
of this data. The user may however restrict the number of bands broadcast
from each GEO satellite to a more sensible level, and the bands nearest to
the GEO position are then used. The user may also define which latitude
and longitude grid points are valid globally, and this determines which
points are used within each band. The set of valid iono grid points does not
change unless an IODI update time is specified for an SBAS satellite. In this
case a second set of user defined iono grid points is applied (for this
satellite), and IODI is also incremented.
Parameter No.
of
Bits
Number of Bands being broadcast
4
Band Number
4
Issue of Data – IODI
2
IGP Mask
201
Spare 1
Number of Bands being broadcast
= 3
Band Number
= 1
Issue of Data – IODI
= 0
The complete contiguous 212 bit data block and its hexadecimal equivalent
is shown below:
0011 0001 0000 1111 1111 0000 0000 0111 1111 1000 0100
0100 0000 0100 0100 0001 1111 1100 0000 0001 1111 1100
0001 0000 0000 0000 0001 0000 1111 1111 1000 0000 1111
1111 1000 0100 0000 0000 0000 0100 0001 1111 1100 0000
0001 1111 1100 0001 0001 0000 0001 0001 0000
Hex:
31 0F F0 07 F8 44 04 41 FC 01 FC 10 00
10 FF 80 FF 84 00 04 1F C0 1F C1 10 11 0
Band Number
= 2
Issue of Data – IODI
= 0
0011 0010 0001 1111 1110 0000 0000 1111 1111 0000 1000
1001 0000 0000 1000 0011 1111 1100 0000 0111 1111 1000
0001 0000 0000 0000 0001 0000 1111 1111 0000 0000 0111
1111 1000 0100 0100 0000 0100 0100 0001 1111 1100 0000
0001 1111 1100 0001 0000 0000 0000 0001 0000