190-00266-01
GPS 15H & 15L Technical Specifications
Rev. D
Page 15
4.2
TRANSMITTED NMEA 0183 SENTENCES
The subsequent paragraphs define the sentences that can be transmitted on COM 1 by the GPS sensor.
4.2.1
Sentence Transmission Rate
Sentences are transmitted with respect to the user-selected baud rate.
Regardless of the selected baud rate, the information transmitted by the GPS sensor is referenced to the
one-pulse-per-second output pulse immediately preceding the GPRMC sentence, or whichever sentence is
output first in the burst (see Table 3 below).
The GPS sensor transmits each sentence (except where noted in particular transmitted sentence
descriptions) at a periodic rate based on the user-selected baud rate and user-selected output sentences. The
GPS sensor transmits the selected sentences contiguously. The contiguous transmission starts at a GPS
second boundary. Determine the length of the transmission with the following equation and Tables 3 and 4:
total characters to be transmitted
length of transmission = ---------------------------------------------
characters
transmitted
per
second
Sentence Output
by
Default? Maximum
Characters
GPRMC
74
GPGGA
82
GPGSA
66
GPGSV
70
PGRME
35
GPGLL
44
GPVTG
42
PGRMV
32
PGRMF
82
PGRMB
40
PGRMM
32
PGRMT
Once per minute
50
Table 3: NMEA 0183 Output Sentence Order and Size
Baud Characters
per
Second
300 30
600 60
1200 120
2400 240
4800 480
9600 960
19200 1920
38400 3840
Table 4: Characters per Second for Available Baud Rates
The maximum number of fields allowed in a single sentence is 82 characters including delimiters. Values
in the table include the sentence start delimiter character “$” and the termination delimiter <CR><LF>. The
factory set defaults result in a once per second transmission at the NMEA 0183 specification transmission
rate of 4800 baud.