USGlobalsat EM-408 - Manual (Page 12)

EM-408
Specifications are subject to be changed without notice.
Page 12 of 14
Version 1.4.1
D.) Query/Rate Control ID:103 Query standard NMEA message and/or set output rate
This command is used to control standard NMEA data output messages: GGA, GLL, GSA, GSV,
RMC, and VTG. Using this command message, standard NMEA message is polled once, or
setup for periodic output. In addition, checksums may also be enable or disable contingent on
receiving program requirements. NMEA message settings are stored in a battery-backed
memory for each entry when the message is accepted.
Format:
$PSRF103,<msg>,<mode>,<rate>,<cksumEnable>*CKSUM<CR><LF>
<msg> 0=GGA,1=GLL,2=GSA,3=GSV,4=RMC,5=VTG
<mode> 0=SetRate,1=Query
<rate> Output every <rate>seconds, off=0,max=255
<cksumEnable> 0=disable Checksum,1=Enable checksum for specified message
Example 1: Query the GGA message with checksum enabled
$PSRF103,00,01,00,01*25
Example 2: Enable VTG message for a 1Hz constant output with checksum enabled
$PSRF103,05,00,01,01*20
Example 3: Disable VTG message
$PSRF103,05,00,00,01*21
E.) LLA Navigation initialization ID:104 Parameters required to start using Lat/Lon/Alt
This command is used to initialize the GPS module for a “Warm” start, providing real-time
position (Latitude, Longitude, Altitude coordinates), clock offset, and time. This action enables
the GPS receiver to search for the necessary satellite signals at the correct signal parameters.
The newly acquired and stored satellite data will enable the receiver to acquire signals more
quickly, and thus, generate a rapid navigational solution.
When a valid LLA Navigation Initialization command is receive, then the receiver will restart
using the input parameters as a basis for satellite selection and acquisition.
Format:
$PSRF104,<Lat>,<Lon>,<Alt>,<ClkOffset>,<TimeOfWeek>,<WeekNo>,
<ChannelCount>, <ResetCfg>*CKSUM<CR><LF>
<Lat> Latitude position, assumed positive north of equator and
negative south of equator float, possibly signed
<Lon> Longitude position, it is assumed positive east of Greenwich
and negative west of Greenwich Float, possibly signed
<Alt>
Altitude position float, possibly signed