4.2NMEA Transmitted Sentences

The subsequent paragraphs define the sentences which can be transmitted on TXD1 by the GPS 35LP receivers.

4.2.1Sentence 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 35LP is referenced to the one-pulse-per-second output pulse immediately preceding the GPRMC sentence.

The GPS 35LP 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 sensor board will transmit the selected sentences contiguously. The contiguous transmission starts at a GPS second boundary. The length of the transmission can be determined by the following equation and tables:

 

total characters to be transmitted

length = --------------------------------------------

 

characters transmitted per sec

Baud

characters_transmitted_per_sec

300

30

600

60

1200

120

2400

240

4800

480

9600

960

19200

1920

Sentence

max_characters

GPGGA

81

GPGSA

66

GPGSV

210

GPRMC

74

GPVTG

42

PGRMB

26

PGRME

35

PGRMT

50

PGRMV

32

PGRMF

82

LCGLL

44

LCVTG

39

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 will result in a once per second transmission at the NMEA specification transmission rate of 4800 baud.

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