Linx Technologies RXM-GPS-FM - Manual (Page 16)

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SBAS Enable
This enables and disables SBAS.
Mode = SBAS Mode
0 = disabled
1 = enabled
A satellite-based augmentation system (SBAS) sends additional information
in the satellite transmissions to improve accuracy and reliability. Ground
stations at accurately surveyed locations measure the satellite signals or
other environmental factors that may impact the signal received by users.
Correction information is then sent to the satellites and broadcast to the
users. Disabling this feature also disables automatic DGPS.
The following example enables SBAS.
$PMTK313,1*2E<CR><LF>
The following example reads the current SBAS configuration and the
module responds with SBAS is enabled.
$PMTK413*34<CR><LF>
$PMTK513,1*28<CR><LF>
SBAS Enable Command and Response
Write Message
Start Msg ID Mode Checksum End
$PMTK 313 ,Mode *Cksum <CR><LF>
Acknowledge Response Message
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,313 ,Flg *Cksum <CR><LF>
Read Message
Start Msg ID Checksum End
$PMTK 413 *34 <CR><LF>
Response Message
Start Msg ID Mode Checksum End
$PMTK 513 ,Mode *Cksum <CR><LF>
Figure 30: SBAS Enable Command and Response
DGPS Source
This enables or disables DGPS mode and configures its source.
Mode = DGPS source mode
0 = No DGPS source
1 = RTCM
2 = WAAS
Differential Global Positioning System (DGPS) enhances GPS by using
fixed, ground-based reference stations that broadcast the difference
between the positions indicated by the satellite systems and the known
fixed positions. The Radio Technical Commission for Maritime Services
(RTCM) is an international standards organization that has a standard for
DGPS. Wide Area Augmentation System (WAAS) is maintained by the FAA
to improve aircraft navigation. This setting automatically switches among
WAAS, EGNOS, MSAS and GAGAN when detected in covered regions
The following example sets the DGPS source to RTCM.
$PMTK301,1*2D<CR><LF>
The following example reads the current DGPS source and the module
responds with the DGPS source as RTCM.
$PMTK401*37<CR><LF>
$PMTK501,1*2B<CR><LF>
DGPS Souce Command and Response
Write Message
Start Msg ID Mode Checksum End
$PMTK 301 ,Mode *Cksum <CR><LF>
Acknowledge Response Message
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,301 ,Flg *Cksum <CR><LF>
Read Message
Start Msg ID Checksum End
$PMTK 401 *37 <CR><LF>
Response Message
Start Msg ID Mode Checksum End
$PMTK 501 ,Mode *Cksum <CR><LF>
Figure 29: DGPS Source Command and Response