NMEA Standard Logs

Platform:

OEM719, OEM729, OEM7500, OEM7600, OEM7700, OEM7720, PwrPak7, CPT7, CPT7700, SMART7, SMART2

This log contains NMEA logs.

GLMLA

GLONASS Almanac Data

GPALM

Almanac Data

GPGGA

Global Position System Fix Data and Undulation

GPGGALONG

GPS Fix Data, Extra Precision and Undulation

GPGLL

Geographic Position

GPGRS

GPS Range Residuals for Each Satellite

GPGSA

GPS DOP on Active Satellites

GPGST

Estimated Error in Position Solution

GPGSV

GPS Satellites in View

GPHDT

NMEA Heading Log (ALIGN)

GPRMB

Navigation Information

GPRMC

GPS Specific Information

GPVTG

Track Made Good and Ground Speed

GPZDA

UTC Time and Date

The NMEA log structures follow format standards as adopted by the National Marine Electronics Association. The reference document used is "Standard For Interfacing Marine Electronic Devices NMEA 0183 Version 3.01". For further information, refer to www.nmea.org. The following table contains excerpts from Table 6 of the NMEA Standard which defines the variables for the NMEA logs. The actual format for each parameter is indicated after the description.

See the Note in the GPGGA log that applies to all NMEA logs.

 

  1. Spaces may only be used in variable text fields.

  2. A negative sign "-" (HEX 2D) is the first character in a Field if the value is negative. The sign is omitted if the value is positive.

  3. All data fields are delimited by a comma (,).

  4. Null fields are indicated by no data between two commas (,,). Null fields indicate invalid data or no data available.

  5. The NMEA Standard requires that message length be limited to 82 characters.

Field Type

Symbol

Definition

Special Format Fields

Status

A

Single character field:

A = Yes, Data Valid, Warning Flag Clear

V = No, Data Invalid, Warning Flag Set

Latitude

llll.ll

Fixed/Variable length field:

degrees|minutes.decimal - 2 fixed digits of degrees, 2 fixed digits of mins and a variable number of digits for decimal-fraction of minutes. Leading zeros always included for degrees and minutes to maintain fixed length. The decimal point and associated decimal-fraction are optional if full resolution is not required

Longitude

yyyyy.yy

Fixed/Variable length field:

degrees|minutes.decimal - 3 fixed digits of degrees, 2 fixed digits of minutes and a variable number of digits for decimal-fraction of minutes. Leading zeros always included for degrees and minutes to maintain fixed length. The decimal point and associated decimal-fraction are optional if full resolution is not required

Time

hhmmss.ss

Fixed/Variable length field:

hours|minutes|seconds.decimal - 2 fixed digits of hours, 2 fixed digits of minutes, 2 fixed digits of seconds and variable number of digits for decimal-fraction of seconds. Leading zeros always included for hours, minutes and seconds to maintain fixed length. The decimal point and associated decimal-fraction are optional if full resolution is not required.

Defined field

 

Some fields are specified to contain predefined constants, most often alpha characters. Such a field is indicated in this standard by the presence of one or more valid characters. Excluded from the list of allowable characters are the following which are used to indicate field types within this standard:

"A", "a", "c", "hh", "hhmmss.ss", "llll.ll", "x", "yyyyy.yy"

Numeric Value Fields

Variable numbers

x.x

Variable length integer or floating numeric field. Optional leading and trailing zeros. The decimal point and associated decimal-fraction are optional if full resolution is not required
(example: 73.10 = 73.1 = 073.1 = 73)

Fixed HEX field

hh___

Fixed length HEX numbers only, MSB on the left

Information Fields

Variable text

c--c

Variable length valid character field

Fixed alpha field

aa___

Fixed length field of uppercase or lowercase alpha characters

Fixed number field

xx___

Fixed length field of numeric characters

Fixed text field

cc___

Fixed length field of valid characters