GPGGALONG

Fix data, extra precision and undulation

Platform:

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

This log contains, time, position, undulation and fix related data of the GNSS receiver. This is output as a GPGGA log but the GPGGALONG log differs from the normal GPGGA log by its extra precision. See also Table: Position Precision of NMEA Logs.

The GPGGALONG log outputs these messages without waiting for a valid almanac. Instead, it uses a UTC time, calculated with default parameters. In this case, the UTC time status is set to WARNING since it may not be one hundred percent accurate. When a valid almanac is available, the receiver uses the real parameters. Then the UTC time status is set to VALID.

The GPGGALONG log can be customized using the NMEAFORMAT command.

When the solution type is INS (SPAN models), the DOPs in the GPGGALONG log are calculated at a 1 Hz rate.
To determine if the receiver is providing an INS solution, check the pos type field in the BESTPOS log.

Message ID: 521

Log Type: Synch

Recommended Input:

log gpggalong ontime 1

Example:

$GPGGA,202601.00,5109.0262339,N,11401.8407317,W,5,40,0.5,1097.350,M,-17.00,M,09,TSTR*5F

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

Field

Structure

Description

Symbol

Example

1

$GPGGALONG

Log header

 

$GPGGA

2

utc

UTC time status of position (hours/minutes/seconds/ decimal seconds)

hhmmss.ss

202126.00

3

lat

Latitude (DDmm.mm)

llll.ll

5106.9847029

4

lat dir

Latitude direction (N = North, S = South)

a

N

5

lon

Longitude (DDDmm.mm)

yyyyy.yy

11402.2986286

6

lon dir

Longitude direction (E = East, W = West)

a

W

7

GPS qual

Refer to Table: GPS Quality Indicators

x

1

8

# sats

Number of satellites in use (00-12). May be different to the number in view

xx

10

9

hdop

Horizontal dilution of precision

x.x

1.0

10

alt

Antenna altitude above/below msl

x.x

1062.376

11

units

Units of antenna altitude (M = metres)

M

M

12

undulation

Undulation - the relationship between the geoid and the WGS84 ellipsoid

x.x

-16.271

13

u-units

Units of undulation (M = metres)

M

M

14

age

Age of Differential GPS data (in seconds)

The maximum age reported here is limited to 99 seconds.

xx

10
(empty when no differential data is present)

15

stn ID

Differential base station ID, 0000-1023

xxxx

AAAA
(empty when no differential data is present)

16

*xx

Check sum

*hh

*48

17

[CR][LF]

Sentence terminator

 

[CR][LF]
Position Precision of NMEA Logs

NMEA Log

Latitude
(# of decimal places)

Longitude
(# of decimal places)

Altitude
(# of decimal places)

GPGGA

4

4

2

GPGGALONG

7

7

3

GPGLL

7

7

N/A

GPRMC

7

7

N/A

Refer to the BESTPOS log and Table: Supplemental Position Types and NMEA Equivalents.