B2: Used Symbols For Describing The Nmea Formats - Leica GR10 Operational Manual

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B2: Used symbols for describing the NMEA formats

Background information
NMEA messages consist of various fields. The fields are:
•
Header
•
Special format fields
•
Numeric value fields
•
Information fields
•
Null fields
Certain symbols are used as identifier for the field types. These symbols are described in this section.
Header
Symbol Field
$ -
--ccc Address
Special format fields
Symbol Field
A Status
llll.ll Latitude
yyyyy.yy Longitude
370
Description
Start of sentence
•
-- = alphanumeric characters identifying
the talker
Options:
GP = GPS only
GL = GLONASS only
GN = Global Navigation Satellite System
•
ccc = alphanumeric characters
identifying the data type and string
format of the successive fields. This is
usually the name of the message.
Description
•
A = Yes, Data Valid, Warning Flag Clear
•
V = No, Data Invalid, Warning Flag Set
•
Degreesminutes.decimal
•
Two fixed digits of degrees, two fixed
digits of minutes and a variable number
of digits for decimal fraction of minutes.
•
Leading zeros are always included for
degrees and minutes to maintain fixed
length.
•
Degreesminutes.decimal
•
Three fixed digits of degrees, two fixed
digits of minutes and a variable number
of digits for decimal fraction of minutes.
•
Leading zeros are always included for
degrees and minutes to maintain fixed
Example
$
GPGGA
Example
V
4724.538950
00937.046785