MX575A/B DGPS Compass
59
Beacon Database Search Mode ($GPMSK,305):
This operating mode has been added to the MX575 beacon receiver in order to be
compliant with the specification IEC 61108-4 for ship borne DGPS maritime radio
beacon receiver equipment.
The basic operation is outlined below.
1. The receiver will determine the 10 closest beacon stations after the GPS
receiver has calculated a valid position fix. The list can be accessed using
the command $PCSI,3,2*.
2. The primary beacon channel tries to tune to the closest available station,
using the frequency and bit rate specified in the station database.
3. The background channel tunes to the frequency of the closest station using
an alternate bit rate.
4. The primary channel retunes to the alternate bit rate if lock is achieved on
the background channel (with acceptable station health and WER).
5. The background channel continually searches for a closer station using the
station database once a lock is achieved on the primary channel.
6. The primary channel will remain tuned to the same station unless one of the
following occurs:
• Word error rate (WER) drops below 10%
• Station becomes unhealthy or unmonitored
• Background channel finds a closer station
• Position changes enough to affect station list.
This command has the following format:
$GPMSK,305,D,,D<CR><LF>
