Saw: sbas almanac data, Reminder on how to output sag messages – Spectra Precision ProMark 800 Reference Manual User Manual

Page 410

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398

Output Message Library

Reminder on How

to Output SAG

Messages

Use the $PASHS,RAW command with the syntax below:

$PASHS,RAW,SAG,<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 SAG
messages on port A at a rate of 15 seconds:

$PASHS,RAW,SAG,A,ON,15

SAW: SBAS Almanac Data

This message contains almanac data for one SBAS satellite.

The message is as follows:

$PASHR,SAW,<structure>

The message’s binary structure is described in the table
below.

Float

4

Reference time of longitude of first node
(seconds)

w

Float

4

Argument of perigee (semicircles)

Float

Af0

4

Correction to mean value (43200 s) of
Draconic period

Float

Af1

4

Af1=d(Af0)/dt(sec/sec)

Float

4

Satellite clock offset (seconds)

Unsigned short Checksum 2

The checksum is computed by breaking
the structure into 21 unsigned shorts, add-
ing them together, and taking the least sig-
nificant 16 bits of the result.

Total

44

Type

Name

Size

Contents

Type

Name

Size

Contents

char Id

1

Data

ID

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