Product Manual

401
Output Message Library
SNW: SBAS Ephemeris Data
This message contains the SBAS ephemeris data for one
satellite.
The message is as follows:
$PASHR,SNW,<structure>
The message’s binary structure is described in the table
below.
Reminder on How
to Output SNW
Messages
Use the $PASHS,RAW command with the syntax below:
$PASHS,RAW,SNW,<port_ID>,ON,<Rate>
For more details on the $PASHS,RAW command, refer to the
Set Command Library Chapter.
As an example, the command below will output SNW
messages on port A at a rate of 15 seconds:
$PASHS,RAW,SNW,A,ON,15
Type Name Size Contents
char - 1 Spare field
char accuracy 1 Accuracy
long T0 4
Ephemeris data reference time within the
day expressed in the SBAS time scale (sec-
onds)
double 3*8 Satellite ECEF X,Y,Z coordinates (meters)
float 3*4
Satellite ECEF velocity X’, Y’, Z’ coordinates
(m/s)
float 3*4 Satellite ECEF acceleration X’’,Y’’,Z’’ (m/s2)
float aGf0 4
Time offset between satellite time scale and
SBAS system time scale (seconds)
float aGf1 4
Time drift between satellite time scale and
SBAS system time scale (seconds)
long tow 4
Time within week in GPS time scale when
SBAS ephemeris was received
char wn 1
Week number in GPS time scale when
SBAS ephemeris was received
char prn 1 Satellite number (33 to 51)
Unsigned
short
Checksum 2
The checksum is computed by breaking the
structure into 34 unsigned shorts, adding
them together, and taking the least signifi-
cant 16 bits of the result.
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