Hemisphere GPS MBX-4, User Manual

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4: NMEA 0183 Interface
(0 to 100 seconds). When power is cycled, the status output interval
resets to zero.
CRMSS is the MBX-4 performance status message, output every n
seconds, and is discussed in Chapter 4.
The MBX-4 provides the above response to this $GPMSK message, and
immediately tunes to the optimum beacon station, provided a valid
beacon almanac is present in receiver memory. Without a valid
almanac, the beacon receiver will perform a Global Search to identify
candidate stations in the area.
Proprietary Commands
The following subsections describe the selection of Hemisphere GPS
proprietary NMEA-0183 formatted commands, and their responses.
Wipe Search Command ($PCSI,4) - The Wipe Search command
instructs the MBX-4 to erase all parameters within the beacon almanac
and to initiate a new Global Search to identify the beacon signals
available for a particular area. The command has the following form:
$PCSI,4<CR><LF>
MBX-4 Response:
$PCSI,ACK,4<CR><LF>
When this command has been issued in Manual Tune mode, the
receiver will initiate a new Global Search when commanded to
Automatic Tune mode. If the receiver is operating in its Automatic
Background Search mode, a new Global Search will begin immediately.
Note: If the “n” field in this message is non-zero, the status data
message output by the MBX-4 may interrupt the flow of RTCM
messages to the GPS receiver.