.. _headlabel-refx-data-89:

Data 89 (GSV)
=============

The information of GSV (GNSS Satellites in View).

Each SV occupies 6 bytes, including 'GNSS ID', 'SV ID', 'Signal Strength', 'Elevation' and 'Azimuth'.

The frame format of the Data **89** unit is as follows:

.. code-block:: none

   For example (Total 21 bytes):
   59 13 03 03 02 24 11 00 37 03 05 30 45 01 02 03 06 28 18 00 9A

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.. table::
   :width: 100%
   :widths: auto

   +---------+-------------------------+---------------------+---------------+------------------------------------------+--------------+
   | Parts   | Fields                                        | Length (Byte) | Range/Format                             | Default      |
   +=========+=========================+=====================+===============+==========================================+==============+
   | ID      | Data ID                                       | 1             | 59H (89)                                 | 59H (89)     |
   +---------+-------------------------+---------------------+---------------+------------------------------------------+--------------+
   | Length  | Data Length                                   | 1 or 2        | 00H or 01H-7FH or 8085H-8181H            |              |
   +---------+-------------------------+---------------------+---------------+------------------------------------------+--------------+
   | Content | `Number`                                      | 1             | 00H-15H or 16H-40H                       |              |
   +         +-------------------------+---------------------+---------------+------------------------------------------+--------------+
   |         |  The first SV           | `GNSS ID`           | 1             | 00H-06H                                  |              |
   +         +                         +---------------------+---------------+------------------------------------------+--------------+
   |         |                         | `SV ID`             | 1             | 00H-FFH                                  |              |
   +         +                         +---------------------+---------------+------------------------------------------+--------------+
   |         |                         | `Signal Strength`   | 1             | 00H-63H (dBHz)                           |              |
   +         +                         +---------------------+---------------+------------------------------------------+--------------+
   |         |                         | `Elevation`         | 1             | 00H-5AH (degrees)                        |              |
   +         +                         +---------------------+---------------+------------------------------------------+--------------+
   |         |                         | `Azimuth`           | 2             | 00000H-0167H (degrees)                   |              |
   +         +-------------------------+---------------------+---------------+------------------------------------------+--------------+
   |         | ...                                           |               |                                          |              |
   +---------+-------------------------+---------------------+---------------+------------------------------------------+--------------+

- `Number`

  Indicates how many satellites the following data comes from.
  If the value of this field is 00H, no other data is included (such as 'GNSS ID', 'SV ID', 'Signal Strength', 'Elevation', 'Azimuth', etc.).

- `GNSS ID`

  GNSS ID indicates the GNSS type.

  - **00H** - GPS.

  - **01H** - SBAS.

  - **02H** - Galileo.

  - **03H** - BeiDou.

  - **05H** - QZSS.

  - **06H** - GLONASS.

- `SV ID`

  Satellite Vehicle ID.

- `Signal Strength`

  Signal strength (C/N0). In particular, FFH means invalid value.

- `Elevation`

  Elevation. In particular, FFH means invalid value.

- `Azimuth`

  Azimuth. In particular, FFFFH means invalid value.