Spectra Precision ProMark 800 Reference Manual User Manual

Page 412

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400

Output Message Library

$PASHR,SNG,<structure>

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

Type

Name

Size

Contents

Long

4

Start time of 30-second frame in satellite time
scale tk from which the ephemeris data is
derived; time modulo one day (seconds)

Short

2

Day number of 30-second frame; modulo
four-year period counting from beginning of
last leap year, which corresponds to parame-
ter tb (tb is set within this day number). This
parameter varies within the range 1 to 1461. If
day number=0, the day number is unknown
(absent in navigation frame)

Long

4

Ephemeris data reference time within the day
expressed in GLONASS system time scale =
UTC + 3 hours (seconds)

Float

4

Frequency offset gh of the on-board fre-
quency standard at tb (dimensionless)

Float

4

Bias tn between satellite time scale and
GLONASS system time scale at tb (seconds)

Double

3*8

Satellite ECEF (PZ-90) X, Y, Z coordinates
(km)

Float

3*4

Satellite ECEF (PZ-90) velocity X’, Y’, Z’ (km/
sec)

Float

3*4

Satellite perturbation acceleration X”, Y”, Z”
due to moon and sun (km/sec/sec).

Double

8

Bias between GLONASS system time scale
and UTC + 3 hours time scale tc (seconds)

Char

1

Age of ephemeris parameter En (interval from
moment when ephemeris data was last
uploaded to tb)

Char

1

Combined 3-bit flag (contains П1, П 2, П 3)

Char

1

Satellite health status flag (0=good, 1=bad)

Char

1

Satellite frequency channel number
[-7,…,6]

Short

2

Satellite system number (satellite number
[1,…,24])

Unsigned
short

Check-
sum

2

The checksum is computed by breaking the
structure into 40 unsigned shorts, adding
them together, and taking the least significant
16 bits of the result.

Total

82

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