Transmitted Nmea 0183 Sentences; Sentence Transmission Rate - Garmin GPS 18 Technical Specifications

4.2 TRANSMITTED NMEA 0183 SENTENCES

The subsequent paragraphs define the sentences that can be transmitted by the GPS 18 PC and LVC.
4.2.1

Sentence Transmission Rate

Sentences are transmitted with respect to the user selected baud rate.
The GPS sensor will transmit 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 will transmit the selected sentences contiguously. The length of the transmission can be
determined by the following equation and Tables 2 and 3:
length of transmission
Sentence
GPRMC
GPGGA
GPGSA
GPGSV
PGRME
GPGLL
GPVTG
PGRMV
PGRMF
PGRMB
PGRMT
Table 2: NMEA 0183 Output Sentence Order and Size
Table 3: 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>. For
the GPS 18 PC and LVC, the factory set defaults result in a once per second transmission at the NMEA
0183 specification transmission rate of 4800 baud. For the GPS 18-5Hz, the factory set defaults will result
in a five times per second transmission at 19200 baud.
For the GPS 18 LVC: 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 2 above).
For the GPS 18-5Hz: Regardless of the selected baud rate, the information transmitted by the GPS sensor is
referenced to the preceding five times per second output pulse.
GPS 18 Technical Specifications (190-00307-00)
total characters to be transmitted
= ---------------------------------------------
characters transmitted per second
Output by Default?
(PC and LVC only)
(PC and LVC only)
(18-5Hz only)
(PC and LVC only)
Once per minute
Baud Characters per Second
300 30
600 60
1200 120
2400 240
4800 480
9600 960
19200 1920
38400 3840
Page 15
Maximum Characters
74
82
66
70
35
44
42
32
82
40
50
Rev. D