DGP000814AAA
2-01
H-14
SBAS Correction Data Files
GSS6100 and SimCHAN user manual
© Spirent Communications Plc 2005 - 2007
Hex:
32 1F E0 0F F0 89 00 83 FC 07 F8 10 00
10 FF 00 7F 84 40 44 1F C0 1F C1 00 01 0
Band Number
= 3
Issue of Data – IODI
= 0
0011 0011 0001 1111 1111 0000 0001 1111 1111 0000 1000
0000 0000 0000 1000 0001 1111 1100 0000 0001 1111 1100
0001 0001 0000 0001 0001 0000 1111 1111 0000 0000 0111
1111 1000 0100 0000 0000 0000 0100 0001 1111 1110 0000
0011 1111 1100 0001 0000 0000 0000 0001 0000
Hex:
33 1F F0 1F F0 80 00 81 FC 01 FC 11 01
10 FF 00 7F 84 00 04 1F E0 3F C1 00 01 0
H.1.2.13 Message Type 25: Long Term Satellite Error Corrections
The long-term corrections message contains data to compensate for errors in
satellite position and velocity (if significant), and also clock noise. As the
name implies, these are effects which are expected to change slowly with
time. Motion errors will apply to a GPS satellite if track errors are specified
for this satellite in the GPS constellation file. Similarly clock error will
apply if non-zero values are specified for the clock error terms (
Δ
af0,
Δ
af1,
Δ
af2) in the same file. The error correction values are calculated on every 16
second epoch, and the time of applicability is set to be at least 60 seconds
after the nominal message transmission time.
There are two formats for this message type, with or without velocity
corrections, i.e. velocity codes 1 and 0 respectively. Unless either clock rate
or velocity component corrections are greater than their respective
resolutions in the code 1 message type then the code 0 message type is used.
This message type can contain correction data for two satellites with
velocity code 1, 4 satellites with velocity code 0, or 3 satellites with a
combination of these. The IODP will correspond with that broadcast in the
preceding PRN mask message, but could lag when a change in PRN mask
interrupts a long-term message sequence. The Issue of Data (IOD) will
normally correspond to the current IODE value for the GPS ephemeris data,
but change in this value on a GPS cutover/upload will be delayed for two
minutes.
No long term correction data is broadcast for the SBAS satellites
themselves.
