pulseEKKO PRO
3-System Setup Parameters
47
$GPGSA,A,3,04,30,10,13,24,06,,,,,,,3.2,2.4,2.1*32
F2
$GPGGA,134301.00,4338.192559,N,07938.449176,W,2,06,2.4,153.17,M,-35.09,M,5.0,0118*7A
$GPVTG,314.4,T,,,000.6,N,001.1,K,D*41
$GPGSA,A,3,04,30,10,13,24,06,,,,,,,3.2,2.4,2.1*32
F3
3.3.4.2
Baud Rate
The baud rate is the speed that data is sent from the GPS receiver to the serial port of the DVL. The
available options are: 2400, 4800, 9600 (default) or 19200. Often, the baud rate for GPS units is 4800. If
you are having a problem getting the GPS to work with the DVL, the Baud Rate is the most likely problem.
3.3.4.3
Stop Bits
The available settings for Stop Bits are: 1 (default) or 2.
3.3.4.4
Data Bits
The available settings for Data Bits are: 7 or 8 (default).
3.3.4.5
Parity
The available settings for Parity are: none (default), odd or even.
3.3.4.6
Last NMEA String
The GPS receiver can be set up to send one or more types of data strings. These strings are called
NMEA-0183 strings and each contains positional or other information in specific formats. Each type of
string is specified by a 5-character prefix. There are numerous NMEA strings but examples of three
different NMEA strings (GPGGA, GPVTG and GPGSA) are shown below.
$GPGGA,134713.00,4338.221086,N,07938.421365,W,2,06,2.1,152.51,M,-35.09,M,5.0,0118*79
$GPVTG,34.0,T,,,001.4,N,002.5,K,D*70
$GPGSA,A,3,30,26,10,13,24,06,,,,,,,4.2,2.1,3.6*36
$GPGGA,134713.00,4338.221086,N,07938.421365,W,2,06,2.1,152.51,M,-35.09,M,5.0,0118*79
$GPVTG,34.0,T,,,001.4,N,002.5,K,D*70
$GPGSA,A,3,30,26,10,13,24,06,,,,,,,4.2,2.1,3.6*36
$GPGGA,134713.00,4338.221086,N,07938.421365,W,2,06,2.1,152.51,M,-35.09,M,5.0,0118*79
$GPVTG,34.0,T,,,001.4,N,002.5,K,D*70
$GPGSA,A,3,30,26,10,13,24,06,,,,,,,4.2,2.1,3.6*36
$GPGGA,134713.00,4338.221086,N,07938.421365,W,2,06,2.1,152.51,M,-35.09,M,5.0,0118*79
$GPVTG,34.0,T,,,001.4,N,002.5,K,D*70
$GPGSA,A,3,30,26,10,13,24,06,,,,,,,4.2,2.1,3.6*36
Before using the GPS with the GPR, the DVL software needs to know the prefix of the LAST string being
sent in each group. In the example above, three strings are being sent each time (GPGGA, GPVTG and
GPGSA). Since GPGSA is the last one being sent in each group, the End String needs to be specified as
GPGSA.
To see what the End String is for your particular GPS, run Test GPS with Listing and note the first 5
characters on the last line after each series of strings is written to the screen. These are the 5 characters
that need to be filled in under Last NMEA String.
The Last NMEA String option allows the user to fill in the necessary 5 character GPS prefix. Use the
numbered buttons to change the letters forward in the alphabet. Use the Change Direction button make
the letters go backward in the alphabet.
See the GPS Receiver User’s Guide for details on how to set up the receiver to output specific NMEA
strings or groups of NMEA strings.
