lc79d (a) gnss protocol specification · 2019. 12. 27. · nmea messages supported by the module....

LC79D (A) GNSS

Protocol Specification

GNSS Module Series

Rev. LC79D(A)_GNSS_Protocol_Specification_V1.0

Date: 2019-12-11

Status: Released

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GNSS Module Series LC79D (A) GNSS Protocol Specification

LC79D(A)_GNSS_Protocol_Specification 1 / 44

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About the Document

Revision History

Revision Date Author Description

1.0 2019-12-11 Jenn XIANG Initial



Contents

About the Document ................................................................................................................................... 2

Contents ....................................................................................................................................................... 3

Table Index ................................................................................................................................................... 5

1 Introduction .......................................................................................................................................... 6

2 Commands ............................................................................................................................................ 7

2.1. List of NMEA Proprietary Commands ......................................................................................... 7

2.2. Structure of NMEA Proprietary Commands ................................................................................ 8

2.3. GNSS Commands....................................................................................................................... 9

2.3.1. $PQCOLD ........................................................................................................................ 9

2.3.2. $PQWARM ....................................................................................................................... 9

2.3.3. $PQHOT ......................................................................................................................... 10

2.3.4. $PQSTARTGNSS .......................................................................................................... 10

2.3.5. $PQSTOPGNSS ............................................................................................................ 11

2.3.6. $PQSRR ......................................................................................................................... 11

2.3.7. $PQSETSLEEP ............................................................................................................. 12

2.3.8. $PQGETSLEEP ............................................................................................................. 13

2.3.9. $PQSETGLP .................................................................................................................. 13

2.3.10. $PQGETGLP.................................................................................................................. 14

2.3.11. $PQSETBAUD ............................................................................................................... 15

2.3.12. $PQSETCNST ............................................................................................................... 16

2.3.13. $PQGETCNST ............................................................................................................... 16

2.3.14. $PQSETL5BIAS ............................................................................................................. 17

2.3.15. $PQGETL5BIAS ............................................................................................................ 18

2.3.16. $PQSETASSTIME ......................................................................................................... 19

2.3.17. $PQSETASSPOS .......................................................................................................... 20

2.3.18. $PQSETASSGNSS ........................................................................................................ 20

2.3.19. $PQCFGODO ................................................................................................................ 21

2.3.20. $PQREQODO ................................................................................................................ 22

2.3.21. $PQRESETODO ............................................................................................................ 23

2.3.22. $PQSTARTODO ............................................................................................................ 23

2.3.23. $PQSTOPODO .............................................................................................................. 24

2.3.24. $PQCFGGEOFENCE .................................................................................................... 24

2.3.25. $PQSETGEOFENCE ..................................................................................................... 26

2.3.26. $PQGETGEOFENCE .................................................................................................... 27

2.3.27. $PQREQGEOFENCE .................................................................................................... 27

2.3.28. $PQCFGNMEAMSG ...................................................................................................... 28

2.4. System Commands ................................................................................................................... 29

2.4.1. $PQSAVEPAR ................................................................................................................ 29

2.4.2. $PQRESTOREPAR........................................................................................................ 30

3 Messages ............................................................................................................................................ 31



3.1. NMEA Standard Messages ....................................................................................................... 31

3.1.1. List of NMEA Standard Messages ................................................................................. 31

3.1.2. NMEA Standard Messages Specification ....................................................................... 31

3.1.2.1. $--RMC ................................................................................................................. 32

3.1.2.2. $--GGA.................................................................................................................. 34

3.1.2.3. $--GLL ................................................................................................................... 36

3.1.2.4. $--GSV .................................................................................................................. 37

3.1.2.5. $--GSA .................................................................................................................. 39

3.1.2.6. $--VTG .................................................................................................................. 40

4 Default Configurations ...................................................................................................................... 42

5 Appendix A References ..................................................................................................................... 43



Table Index

TABLE 1: SUMMARY OF NMEA PROPRIETARY COMMANDS ........................................................................ 7

TABLE 2: STRUCTURE OF NMEA PROPRIETARY COMMANDS .................................................................... 8

TABLE 3: LIST OF NMEA STANDARD MESSAGES ........................................................................................ 31

TABLE 4: STRUCTURE OF NMEA STANDARD MESSAGES ......................................................................... 32

TABLE 5: DEFAULT CONFIGURATIONS ......................................................................................................... 42

TABLE 6: RELATED DOCUMENT .................................................................................................................... 43

TABLE 7: TERMS AND ABBREVIATIONS ........................................................................................................ 43



1 Introduction

LC79D GNSS module supports GPS, GLONASS, BeiDou, Galileo, QZSS and NAVIC (IRNSS)

constellations and it provides fast and accurate acquisition. The simultaneously tracking of GPS L1 C/A,

GLONASS L1, BeiDou B1, QZSS L1, Galileo E1, GPS L5, Galileo E5a, NAVIC L5 and QZSS L5 makes

this module an ideal solution for positioning and navigation in various vertical markets.

The following document describes the software commands used for controlling LC79D (A) and the output

NMEA messages supported by the module. LC79D (A) can be controlled and configured through NMEA

proprietary commands defined by Quectel (PQ commands), and it supports output messages at NMEA

0183 standard format protocol to provide various GNSS information.

Please use the commands listed in this user manual. Using other commands that are not listed in this

manual is not under Quectel's responsibility.

NOTE



2 Commands

2.1. List of NMEA Proprietary Commands

The table below summarizes all NMEA proprietary commands defined by Quectel (PQ commands)

supported by LC79D (A).

Table 1: Summary of NMEA Proprietary Commands

Syntax Description

$PQHOT Perform hot start

$PQWARM Perform warm start

$PQCOLD Perform cold start

$PQSTARTGNSS Start GNSS engine

$PQSTOPGNSS Stop GNSS engine

$PQSRR Reset system

$PQSETSLEEP Control Sleep mode

$PQGETSLEEP Get the status of Sleep mode

$PQSETGLP Control GLP mode

$PQGETGLP Get the status of GLP mode

$PQSETBAUD Configure NMEA port baud rate

$PQSETCNST Configure GNSS constellation mask

$PQGETCNST Get the information of constellation mask

$PQSETL5BIAS Configure L5 bias value

$PQGETL5BIAS Query L5 bias value

$PQSETASSTIME Inject GNSS assistant time



2.2. Structure of NMEA Proprietary Commands

Table 2: Structure of NMEA Proprietary Commands

$PQSETASSPOS Inject GNSS assistant position

$PQSETASSGNSS Inject GNSS assistant position and time

$PQCFGODO Configure odometer

$PQREQODO Request odometer value

$PQRESETODO Reset odometer

$PQSTARTODO Start odometer

$PQSTOPODO Stop odometer

$PQCFGGEOFENCE Configure geofence

$PQSETGEOFENCE Enable/disable geofence

$PQGETGEOFENCE Query geofence state

$PQREQGEOFENCE Request geofence

$PQCFGNMEAMSG Configure NMEA message output type

Field Length (Bytes) Description

$ 1 Each NMEA message starts with "$"

Talker ID 1 "P" for proprietary message

NMEA Data type 1 Always "Q" to indicate Quectel proprietary command

Data Field

Packet type Valid characters Packet type

Packet data Variable, depend on

the packet type Data fields, delimited by comma ","

* 1 End character of data field

Checksum 2 A hexadecimal number calculated by exclusive OR

of all characters between "$" and "*"

2 Each NMEA message ends with "CR" and "LF"



2.3. GNSS Commands

2.3.1. $PQCOLD

Perform a cold start.

Synopsis:

$PQCOLD*

Argument:

None.

Result:

Cold start initialization and GNSS engine restart 1).

Example:

$PSTMCOLD*05

2.3.2. $PQWARM

Perform a warm start.

Synopsis:

$PQWARM*

Argument:

None.

Result:

Warm start initialization and GNSS engine restart 1).

Example:

$PQWARM*08

1) It is not a system rebooting.

NOTE



2.3.3. $PQHOT

Perform a hot start.

Synopsis:

$PQHOT*

Argument:

None.

Result:

Hot start initialization and GNSS engine restart 1).

Example:

$PQHOT*52

2.3.4. $PQSTARTGNSS

When the GNSS engine is stopped, for instance waking up from sleep mode or after sending assistant

time/position to the module, the command can be used to start the engine.

Synopsis:

$PQSTARTGNSS*

Argument:

None.



NOTE

NOTE



Result:

in case of no errors, the GNSS engine will be started and the returned message will be:

$PQSTARTGNSSOK*4C

In case of any error, the returned message will be:

$PQSTARTGNSSERROR*10

Example:

$PQSTARTGNSS*48

$PQSTARTGNSSOK*4C

2.3.5. $PQSTOPGNSS

Stop GNSS engine.

Synopsis:

$PQSTOPGNSS*

Argument:

None.

Result:

In case of no errors, the GNSS engine will be stopped and the returned message will be:

$PQSTOPGNSSOK*14


$PQSTOPGNSSERROR*48

Example:

$PQSTOPGNSS*10

$PQSTOPGNSSOK*14

2.3.6. $PQSRR

Execute a system reset. The GNSS firmware will be rebooted.

Synopsis:

$PQSRR*



Argument:

None.

Result:

The GNSS firmware will be rebooted and no message will be sent as a reply.

Example:

$PQSRR*52

2.3.7. $PQSETSLEEP

Enable/disable sleep mode.

Synopsis:

$PQSETSLEEP,*

Argument:

Result:

In case of no errors, the returned message will be:

$PQSETSLEEPOK*08


$PQSETSLEEPERROR*54

Example:

$PQSETSLEEP,1*11

$PQSETSLEEPOK*08

Parameter Format Description

mode Integer

Sleep mode

0 = Disable sleep mode (default)

1 = Enable sleep mode

1. In sleep mode, the UART is inaccessible.

2. When sleep mode is enabled with $PQSETSLEEP,1 and GNSS engine is stopped, the module can

enter sleep mode through pulling down AP_REQ pin.

NOTES



2.3.8. $PQGETSLEEP

Get the status of sleep mode.

Synopsis:

$PQGETSLEEP*

Argument:

None.

Result:


$PQSLEEP,*

The parameter included in the result above is listed as below:


$PQGETSLEEPERROR*40

Example:

$PQGETSLEEP*18

$PQSLEEP,1*53

2.3.9. $PQSETGLP

Enable/disable GNSS Low Power (GLP) mode. GLP is the best power-saving mode during acquisition

and tracking. It helps the module to achieve a balance between performance and power consumption

according to the signal condition.

Synopsis:

$PQSETGLP,*


mode Integer

Sleep mode status

0 = The sleep mode is disabled

1 = The sleep mode is enabled



Argument:

Result:


$PQSETGLPOK*1C


$PQSETGLPERROR*40

Example:

$PQSETGLP,1*05

$PQSETGLPOK*1C

2.3.10. $PQGETGLP

Get the status of GLP mode.

Synopsis:

$PQGETGLP*

Argument:

None.

Result:


$PQGLP,*



mode Integer

GLP mode

0 = Disable GLP mode (default)

1 = Enable GLP mode

The GNSS engine will be restarted if this command is executed successfully.

NOTE




$PQGETGLPERROR*54

Example:

$PQGETGLP*0C

$PQGLP,1*47

2.3.11. $PQSETBAUD

Configure NMEA port baud rate.

Synopsis:

$PQSETBAUD,*

Argument:

Result:


$PQSETBAUDOK*55


$PQSETBAUDERROR*09

Example:

$PQSETBAUD,115200*7A

$PQSETBAUDOK*55


mode Integer

GLP mode status

0 = The GLP mode is disabled

1 = The GLP mode is enabled


baudrate Integer

Supported baud rates (unit: bps):

115200 (default)

230400

460800

921600



2.3.12. $PQSETCNST

Configure the GNSS constellation mask.

Synopsis:

$PQSETCNST,*

Argument:

Result:


$PQSETCNSTOK*4D


$PQSETCNSTERROR*11

Example:

$PQSETCNST,63*60

$PQSETCNSTOK*4D

2.3.13. $PQGETCNST

Get the information of GNSS constellation mask.


mask Integer

It is a bit mask where each bit enables (1 = enable)

or disables (0 = disable) a specific constellation

independently:

bit 0: GPS constellation enabling/disabling

bit 1: GLONASS constellation enabling/disabling

bit 2: Galileo constellation enabling/disabling

bit 3: BeiDou constellation enabling/disabling

bit 4: NAVIC constellation enabling/disabling

bit 5: QZSS constellation enabling/disabling

By default, all constellations are enabled.

The GNSS engine will be restarted if the command is executed successfully.

NOTE



Synopsis:

$PQGETCNST*

Argument:

None.

Result:


$PQCNST,*



$PQGETCNSTERROR*05

Example:

$PQGETCNST*5D

$ $PQCNST,63*22

2.3.14. $PQSETL5BIAS

Configure the L5 bias value. This value is used to correct the delay of L5, and it can be acquired through

connecting the module to QGNSS tool in open sky.

Synopsis:

$PQSETL5BIAS,*


mask Integer

It is a bit mask where each bit enables (1 = enable)

or disables (0 = disable)a specific constellation

independently:

bit 0: GPS constellation enabling/disabling

bit 1: GLONASS constellation enabling/disabling

bit 2: Galileo constellation enabling/disabling

bit 3: BeiDou constellation enabling/disabling

bit 4: NAVIC constellation enabling/disabling

bit 5: QZSS constellation enabling/disabling



Argument:

Result:


$PQSETL5BIASOK*27


$PQSETL5BIASERROR*7B

Example:

$PQSETL5BIAS,14.6*12

$PQSETL5BIASOK*27

$PQSAVEPAR*43

$PQSAVEPAROK*47

2.3.15. $PQGETL5BIAS

Query the current L5 bias value.

Synopsis:

$PQGETL5BIAS*

Argument:

None.

Result:

In case of no errors, the system will output the L5 bias value:

$PQL5BIAS,*



bias Integer The bias value of L5

The configuration takes effect after rebooting, and it must be saved by $PQSAVEPAR (please refer to

Chapter 2.4.1) before rebooting.

NOTE




$PQGETL5BIASERROR*6F

Example:

$PQGETL5BIAS*37

$PQL5BIAS,14.600000*60

2.3.16. $PQSETASSTIME

Inject GNSS assistant time in UTC format. This command should be executed only after stopping GNSS,

otherwise, the execution failure will occur. The time must be later than May 2019.

Synopsis:

$PQSETASSTIME,,,,,,*

Argument:

Result:


$PQSETASSTIMEOK*13


$PQSETASSTIMEERROR*4F


bias Integer The bias value of L5.


year YYYY - Decimal, 4 digits Year (2019-…)

month mm - Decimal, 2 digits Month (01-12)

day dd - Decimal, 2 digits Day of month (01-31)

hour HH - Decimal, 2 digits Hour (00-23)

min MM - Decimal, 2 digits Minute (00-59)

sec SS - Decimal, 2 digits Second (00-59)



Example:

$PQSETASSTIME,2019,06,19,02,30,30*11

$PQSETASSTIMEOK*13

2.3.17. $PQSETASSPOS

Inject GNSS assistant position. This command should be issued only after stopping GNSS, otherwise, the

execution failure will occur.

Synopsis:

$PQSETASSPOS,,,[,,]*

Argument:

Result:


$PQSETASSPOSOK*4A


$PQSETASSPOSERROR*16

Example:

$PQSETASSPOS,31.846357,171.198622,0*6A

$PQSETASSPOSOK*4A

2.3.18. $PQSETASSGNSS

Inject GNSS assistant position and time. This command should be issued only after stopping GNSS,

otherwise, the execution failure will occur. The time must be later than May 2019.


lat DD.DDDDDD Latitude (Degree decimals)

lon DDD.DDDDDD Longitude (Degree decimals)

alt Decimal Altitude in meters

hor_acc Decimal Horizontal accuracy.

This parameter is optional.

ver_acc Decimal Vertical accuracy.

This parameter is optional.



Synopsis:

$PQSETASSGNSS,,,,,,,,,*<

LF>

Argument:

Result:


$PQSETASSGNSSOK*0F


$PQSETASSGNSSERROR*53

Example:

$PQSETASSGNSS,31.846357,171.198622,0,2019,05,05,18,20,22*2E

$PQSETASSGNSSOK*0F

2.3.19. $PQCFGODO

Read or write odometer configurations.

Synopsis:

$PQCFGODO,,,,*


lat DD.DDDDDD Latitude (Degree decimals)

lon DDD.DDDDDD Longitude (Degree decimals)

alt Decimal Altitude in meters

year YYYY - Decimal, 4 digits Year (2019-…)

month mm - Decimal, 2 digits Month (01-12)

day dd - Decimal, 2 digits Day of month (01-31)

hour HH - Decimal, 2 digits Hour (00-23)

min MM - Decimal, 2 digits Minute (00-59)

sec SS - Decimal, 2 digits Second (00-59)



Argument:

Result:


$PQCFGODOOK*03


$PQCFGODOERROR*5F

Example:

$PQCFGODO,1,0,1,0*07

$PQCFGODOOK*03

2.3.20. $PQREQODO

Request the current odometer configuration information.

Synopsis:

$PQREQODO*

Argument:

None.

Result:

In case of no errors, the odometer value will be returned.

$PQODO,*


RW Decimal, 1 digit

Read or write odometer configurations.

0 = Read odometer configurations

1 = Configure odometer

Auto_Start Decimal, 1 digit

Enable or disable odometer to start automatically.

0 = Disable (default)

1 = Enable

MSG_Mode Decimal, 1 digit

Message report mode.

0 = Not output odometer message periodically

1 = Output odometer message periodically (default)

InitVal Decimal Initial value of odometer. Default value: 0.





$PQREQODOERROR*5B

Example:

$PQREQODO*03

$PQODO,0.0*47

2.3.21. $PQRESETODO

Reset odometer. This command will clear the current odometer value.

Synopsis:

$PQRESETODO*

Argument:

None.

Result:


$PQRESETODOOK*14


$PQRESETODOERROR*48

Example:

$PQRESETODO*10

$PQRESETODOOK*14

2.3.22. $PQSTARTODO

Start odometer.

Synopsis:

$PQSTARTODO*


Odo_Val Decimal The current odometer value.



Argument:

None.

Result:


$PQSTARTODOOK*01


$PQSTARTODOERROR*5D

Example:

$PQSTARTODO*05

$PQSTARTODOOK*01

2.3.23. $PQSTOPODO

Stop odometer.

Synopsis:

$PQSTOPODO*

Argument:

None.

Result:


$PQSTOPODOOK*59


$PQSTOPODOERROR*05

Example:

$PQSTOPODO*10

$PQSTOPODOOK*59

2.3.24. $PQCFGGEOFENCE

Read or write geofence configurations.



Synopsis:

$PQCFGGEOFENCE,,,,,,,[,,,,,]*

Argument:


RW Decimal, 1 digit

Read or write geofence configurations.

0 = Read geofence configurations

1 = Configure geofence

GeoID Decimal, 1 digit Geofence ID. Range: 0-2.

GeoMode Decimal, 1 digit

Geofence message report mode.

0 = Do not report

1 = Report while entering the geo-fence

2 = Report while leaving the geo-fence

3 = Report when entering or leaving the geo-fence

GeoShape Decimal, 1 digit

Geofence shape.

0 = Circle with a radius

1 = Circle with one point on circle

2 = Triangle

3 = Quadrangle (such as square, rectangle

trapezium, etc.)

Lat0 Float The latitude of the first point.

Long0 Float The longitude of the first point.

Lat1/Radius Float

If the geofence shape is a circle with a certain

radius, this value will be the radius of the circle,

otherwise this value will be the latitude of the

second point.

Long1 Float The longitude of the second point.

Lat2 Float The latitude of the third point.

Long2 Float The longitude of the third point.

Lat3 Float The latitude of the fourth point.

Long3 Float The longitude of the fourth point.



Result:


$PQCFGGEOFENCEOK*41


$PQCFGGEOFENCEERROR*1D

Example:

//If the geofence shape is a circle with a radius.

$PQCFGGEOFENCE,1,0,3,0,31.5863,117.5686,2000*59

$PQCFGGEOFENCEOK*41

//If the geofence shape is circle with one point on circle.

$PQCFGGEOFENCE,1,0,3,1,31.5863,117.5686,36.5548,118.4523*47

$PQCFGGEOFENCEOK*41

2.3.25. $PQSETGEOFENCE

Enable/disable geofence.

Synopsis:

$PQSETGEOFENCE,*

Argument:

Result:


$PQSETGEOFENCEOK*41


$PQSETGEOFENCEERROR*1D

Example:

$PQSETGEOFENCE,0*59

$PQSETGEOFENCEOK*41


GeoEn Decimal, 1 digit

Enable or disable geofence.

0 = Disable geofence (default)

1 = Enable geofence



2.3.26. $PQGETGEOFENCE

Query whether geofence is enabled.

Synopsis:

$PQGETGEOFENCE*

Argument:

None.

Result:


$PQGEOFENCE,*

The parameters included in the result above are listed below:


$PQGETGEOFENCEERROR*09

Example:

$PQGETGEOFENCE*51

$PQGEOFENCE,0*1B

2.3.27. $PQREQGEOFENCE

Request the geofence status so as to identify that the position is inside or outside of the geofence.

Synopsis:

$PQREQGEOFENCE,*

Argument:


GeoEn Decimal, 1 digit

Geofence state.

0 = Geofence is disabled

1 = Geofence is enabled





Result:


$PQGEOFENCESTATUS,,*

The parameters included in the result above are listed as below:


$PQREQGEOFENCEERROR*19

Example:

$PQREQGEOFENCE,0*5D

$PQGEOFENCESTATUS,0,0*13

2.3.28. $PQCFGNMEAMSG

Configure the type of output NMEA messages.

Synopsis:

$PQCFGNMEAMSG,,,,,,,*

Argument:



GeoStatus Decimal, 1 digit

Geofencing status for each geofence shape:

0 = Unknow

1 = Inside

2 = Outside


RW Decimal, 1 digit

Read or write NMEA message configurations.

0 = Read NMEA message configurations

1 = Configure NMEA message

NMEA_GGA Decimal, 1 digit 0 = Disable GGA messages

1 = Enable GGA messages

NMEA_RMC Decimal, 1 digit 0 = Disable RMC messages

1 = Enable RMC messages

NMEA_GSV Decimal, 1 digit 0 = Disable GSV messages

1 = Enable GSV messages



Result:


$PQCFGNMEAMSGERROR*45


$PQCFGNMEAMSGOK*19

Example:

$PQCFGNMEAMSG,1,1,1,1,1,1,1*00

$PQCFGNMEAMSGOK*19

2.4. System Commands

2.4.1. $PQSAVEPAR

Save configurations of GNSS commands into NVM.

Synopsis:

$PQSAVEPAR*

Argument:

None.

Result:


$PQSAVEPAROK*47


$PQSETASSPOSERROR*16

NMEA_GSA Decimal, 1 digit 0 = Disable GSA messages

1 = Enable GSA messages

NMEA_GLL Decimal, 1 digit 0 = Disable GLL messages

1 = Enable GLL messages

NMEA_VTG Decimal, 1 digit 0 = Disable VTG messages

1 = Enable VTG messages



Example:

$PQSAVEPAR*43

$PQSAVEPAROK*47

2.4.2. $PQRESTOREPAR

Restore all configurations to default values.

Synopsis:

$PQRESTOREPAR*

Argument:

None.

Result:


$PQRESTOREPAROK*0E


$PQRESTOREPARERROR*52

Example:

$PQRESTOREPAR*0A

$PQRESTOREPAROK*0E



3 Messages

3.1. NMEA Standard Messages

This chapter introduces the NMEA standard messages supported by LC79D (A).

3.1.1. List of NMEA Standard Messages

LC79D (A) supports output of the following six types of NMEA standard messages by default.

Table 3: List of NMEA Standard Messages

3.1.2. NMEA Standard Messages Specification

These messages are defined within the "NMEA 0183" specification. The structure of NMEA standard

messages is shown as below:

Syntax Default Description

$--RMC ON NMEA: Recommended Minimum Specific GNSS Data

$--GGA ON NMEA: Global Position System Fix Data

$--GLL ON NMEA: Geographic Position - Latitude and Longitude

$--GSV ON NMEA: GNSS Satellites in View

$--GSA ON NMEA: GNSS DOP and Active Satellites

$--VTG ON NMEA: Course Over Ground and Ground Speed



Table 4: Structure of NMEA Standard Messages

3.1.2.1. $--RMC

Recommended Minimum Specific GNSS Data. Time, date, position, course and speed data provided by a

GNSS receiver.

Format:

$RMC,,,,,,,,,,,,,*

Example:

$GNRMC,000010.00,V,,,,,,,020712,,,N,V*1E

$GNRMC,060512.00,A,3150.788156,N,11711.922383,E,0.0,,311019,,,A,V*1B

Field Format Description

$ Char Each NMEA message starts with "$"

TalkerID String, 2 characters

The talker ID.

GP: For GPS

GL: For GLONASS

GA: For Galileo

GB: For BeiDou

GI: For NAVIC (IRNSS)

Field Length (Bytes) Description

$ 1 Each NMEA message starts with "$"

Talker ID 1~2

GP: If the system works in GPS only mode

GL: If the system works in GLONASS only mode

GA: If the system works in Galileo only mode

GB: If the system works in BeiDou only mode

GI: If the system works in NAVIC only mode

GQ: If the system works in QZSS only mode

GN: If the system works in multi-constellation mode

NMEA

Message ID 3 NMEA message ID

Data Field Variable, depend on the

NMEA message type Data fields, delimited by comma ","

* 1 End character of data field

Checksum 2 A hexadecimal number calculated by exclusive OR of

all characters between "$" and "*"

2 Each NMEA message ends with "CR" and "LF"



GQ: For QZSS

GN: For multi-constellation mode

Timestamp hhmmss.ss

UTC time of GNSS sample:

hh: hours (Fixed two digits)

mm: minutes (Fixed two digits)

ss: seconds (Fixed two digits)

.ss: decimal fraction of seconds

Status A or V V = Invalid

A = Valid

Lat DDMM.MMMMMM

Latitude as degrees:

DD: Degrees (Fixed two digits)

MM: Minutes (Fixed two digits)

.MMMMMM: Decimal fraction of minutes

N/S N or S

Latitude direction:

N = North

S = South

Please note that this field is empty in case of an

invalid value.

Long DDDMM.MMMMMM

Longitude as degrees:

DDD: Degrees (Fixed three digits)




invalid value.

E/W E or W

Longitude direction:

E = East

W = West


invalid value.

SOG x.x, variable length field

Speed over ground in knots.


invalid value.

COG x.x, variable length field

Course over ground. The maximum value is

359.9.


invalid value.

Date ddmmyy Date in format ddmmyy

MagVar Empty Not supported

MagVarDir Empty Not supported

Mode D, A, N or E Positioning system mode indicator:

D = Differential mode



A = Autonomous mode

N = Data not valid

E = Estimated (dead reckoning) mode

NavStatus S, C, U or V

Navigational status.

S = Safe

C = Caution

U = Unsafe

V = Navigational status not valid. Equipment is

not providing navigational status indication.

* End character of data field

Checksum Hexadecimal checksum

Each NMEA message ends with "CR" and "LF"

3.1.2.2. $--GGA

Global Positioning System Fix Data. Time, position and fix related data for a GNSS receiver.

Format:

$GGA,,,,,,,,,,,,,,*

Example:

$GNGGA,000010.00,,,,,0,00,99.0,,M,,M,,*49

$GNGGA,062735.00,3150.788156,N,11711.922383,E,1,12,2.0,90.0,M,,M,,*55




The talker ID.

GP: For GPS

GL: For GLONASS

GA: For Galileo

GB: For BeiDou


GQ: For QZSS


Timestamp hhmmss.ss






Lat DDMM.MMMMMM Latitude as degrees:







invalid value.

N/S N or S

Latitude direction:

N = North

S = South


invalid value.

Long DDDMM.MMMMMM


DDD: Degree (Fixed three digits)




invalid value.

E/W E or W


E = East

W = West


invalid value.

GPSQual Decimal, 1 digit

0 = Fix not available or invalid

1 = GPS, SPS Mode, fix valid

2 = Differential GPS, SPS Mode, fix valid

6 = Estimated (dead reckoning) mode

Sats Decimal, 2 digits Number of satellites in use. Example: 12

HDOP x.x, variable length field Horizontal dilution of precision.

The maximum value is 99.0.

Alt x.x, variable length field Height above mean sea level.

The maximum value is 100000.0 meters.

AltVal M Reference unit for altitude:

M = meters

GeoSep x.x, variable length field Geoidal separation measure in meters.

Geoval M Reference unit for geoidal separation:

M = meters

DGPSAge Empty Not supported

DGPSRef Empty Not supported






3.1.2.3. $--GLL

Geographic Position – Latitude and Longitude. Latitude and longitude of vessel position, time of position

fix and status.

Format:

$GLL,,,,,,,*

Example:

$GNGLL,,,,,000010.00,V,N*55

$GNGLL,3150.788156,N,11711.922383,E,062735.00,A,A*76




The talker ID.

GP: For GPS

GL: For GLONASS

GA: For Galileo

GB: For BeiDou


GQ: For QZSS


Lat DDMM.MMMMMM

Latitude as degrees:




Please note that this field is empty in

case of an invalid value.

N/S N or S

Latitude direction:

N = North

S = South



Long DDDMM.MMMMMM


DDD: Degrees (Fixed three digits)







E/W E or W


E = East

W = West



Timestamp hhmmss.ss






Status A or V

Validity of data:

A = valid

V = invalid

ModeInd A or N

Positioning system mode indicator:

A = Autonomous mode

N = Data not valid



Each NMEA message ends with "CR"

and "LF"

3.1.2.4. $--GSV

GNSS Satellites in View. The GSV sentence provides the number of satellites (SV) in view, satellite ID

numbers, elevation, azimuth, and SNR value. The GSV sentence contains four satellites maximum per

transmission. The total number of sentences being transmitted and the sentence number being

transmitted are indicated in the first two fields.

Format:

$GSV,,,,,,,,…,,,,,*

Example:

$GPGSV,3,1,11,05,09,116,27,10,24,312,44,12,09,141,28,13,14,055,41,1*68

$GPGSV,3,2,11,15,45,045,49,20,52,323,46,24,76,125,26,27,,,19,1*51

$GPGSV,3,3,11,10,24,312,43,24,76,125,13,27,,,19,8*63

$GLGSV,2,1,07,78,45,071,45,77,10,028,39,79,,,16,69,38,327,48,1*43

$GLGSV,2,2,07,84,35,279,21,85,09,331,32,67,09,083,44,1*4D

$GQGSV,2,1,03,01,66,079,38,02,45,132,19,1*6A

$GQGSV,2,2,03,01,66,079,35,8*56

$GBGSV,1,1,04,206,67,338,43,211,13,303,31,216,65,322,41,219,15,096,39,1*71

$GIGSV,1,1,02,03,38,233,23,07,,,25,1*44






The talker ID.

GP: For GPS

GL: For GLONASS

GA: For Galileo

GB: For BeiDou


GQ: For QZSS

GSVAmount Decimal, 1 digit Total amount of GSV messages.

The maximum value is 8.

GSVNumber Decimal, 1 digit Message number.

TotSats Decimal, 2 digits Total number of satellites in view.

The maximum value is 32.

SatxPRN Decimal, 2 digits Satellite ID number used for positioning.

SatxElev Decimal, 2 digits Elevation of satellite in degrees.

Range: 00-90.

SatxAzim Decimal, 3 digits

Azimuth of satellite in degrees, with true

north as the reference plane.

Range: 000-359.

SatxCN0 Decimal, 2 digits Carrier to noise ratio for satellite x in dB.

Range: 00-99.

SignalID Decimal, 1 digit

The signal ID:

For GPS:

1 = L1 C/A

8 = L5-Q

For GLONASS:

1 = G1 C/A

For Galileo:

1 = E5a

2 = E5b

6 = L1-A

For BeiDou:

1 = B1I

For QZSS:

1 = L1 C/A

8 = L5-Q

For NAVIC (IRNSS):

1 = L5-SPS





Each NMEA message ends with "CR"

and "LF"

3.1.2.5. $--GSA

GNSS DOP and Active Satellites. Satellites from different constellations are sent on separate messages.

Format:

$GSA,,,,...,,,,,*

Example:

$GNGSA,A,3,10,13,15,20,,,,,,,,,2.5,2.0,1.5,1*35

$GNGSA,A,3,67,69,77,78,85,,,,,,,,2.5,2.0,1.5,2*3F

$GNGSA,A,3,,,,,,,,,,,,,2.5,2.0,1.5,3*32

$GNGSA,A,3,,,,,,,,,,,,,2.5,2.0,1.5,4*35

$GNGSA,A,3,01,,,,,,,,,,,,2.5,2.0,1.5,5*35

$GNGSA,A,3,,,,,,,,,,,,,2.5,2.0,1.5,6*37




The talker ID.

GP: For GPS

GL: For GLONASS

GA: For Galileo

GB: For BeiDou


GQ: For QZSS


Mode 1 character

M = Manual, forced to operate in 2D or 3D mode

A = Automatic, allowed to automatically switch

2D/3D

CurrentMode Decimal, 1 digit

1 = Fix not available

2 = 2D

3 = 3D

SatPRN(1 to 12) Decimal, 2 or 3 digits Satellite ID number used for positioning

PDOP x.x, variable length field Position dilution of precision.


HDOP x.x, variable length field Horizontal dilution of precision.




VDOP x.x, variable length field Vertical dilution of precision.


SystemID Decimal, 1 digit

GNSS System ID:

1 = GPS

2 = GLONASS

3 = Galileo

4 = BeiDou

5 = QZSS

6 = NAVIC (IRNSS)




3.1.2.6. $--VTG

Course Over Ground & Ground Speed. The actual course and speed relative to the ground.

Format:

$VTG,,T,,M,,N,,K,*

Example:

$GNVTG,,T,,M,0.0,N,0.0,K,A*3D




The talker ID.

GP: For GPS

GL: For GLONASS

GA: For Galileo

GB: For BeiDou


GQ: For QZSS


COGT x.x, variable length field Course over ground, in true north course direction.

COGM x.x, variable length field Course over ground, in magnetic north course

direction

SOGN x.x, variable length field Speed over ground in knots

SOGK x.x, variable length field Speed over ground in kilometers per hour

ModeInd A or N Mode indicator:



A = Autonomous mode

N = Data not valid






4 Default Configurations

Table 5: Default Configurations

Item Default Configuration

NMEA port baud rate 115200bps

Datum WGS84

Rate of position fixing 1Hz

DGPS mode OFF

NMEA output messages RMC, GGA, GLL, GSV, GSA and VTG

GNSS Configuration GPS+BeiDou+GLONASS+Galileo+QZSS+IRNSS



5 Appendix A References

Table 6: Related Document

Table 7: Terms and Abbreviations

SN Document Name Remark

[1] Quectel_LC79D_Hardware_Design LC79D Hardware Design

Abbreviation Description

DGPS Differential Global Positioning System

GGA Global Positioning System Fix Data

GLONASS Global Navigation Satellite System (Russian)

GLP GNSS Low Power

GNSS Global Navigation Satellite System

GPS Global Positioning System

GSA GNSS DOP and Active Satellites

GSV GNSS Satellites in View

HDOP Horizontal Dilution of Precision

NAVIC (IRNSS) NAVigation with Indian Constellation (Indian Regional Navigation Satellite

System)

NMEA National Marine Electronics Association

NVM Non-Volatile Memory

PDOP Position Dilution of Precision

PPS Pulse Per Second



QZSS Quasi-Zenith Satellite System

RMC Recommended Minimum Specific GNSS Data

SBAS Satellite-Based Augmentation System

UTC Universal Time Coordinated

VDOP Vertical Dilution of Precision

WGS84 World Geodetic System 1984

About the DocumentContentsTable Index1 Introduction2 Commands2.1. List of NMEA Proprietary Commands2.2. Structure of NMEA Proprietary Commands2.3. GNSS Commands2.3.1. $PQCOLD2.3.2. $PQWARM2.3.3. $PQHOT2.3.4. $PQSTARTGNSS2.3.5. $PQSTOPGNSS2.3.6. $PQSRR2.3.7. $PQSETSLEEP2.3.8. $PQGETSLEEP2.3.9. $PQSETGLP2.3.10. $PQGETGLP2.3.11. $PQSETBAUD2.3.12. $PQSETCNST2.3.13. $PQGETCNST2.3.14. $PQSETL5BIAS2.3.15. $PQGETL5BIAS2.3.16. $PQSETASSTIME2.3.17. $PQSETASSPOS2.3.18. $PQSETASSGNSS2.3.19. $PQCFGODO2.3.20. $PQREQODO2.3.21. $PQRESETODO2.3.22. $PQSTARTODO2.3.23. $PQSTOPODO2.3.24. $PQCFGGEOFENCE2.3.25. $PQSETGEOFENCE2.3.26. $PQGETGEOFENCE2.3.27. $PQREQGEOFENCE2.3.28. $PQCFGNMEAMSG

2.4. System Commands2.4.1. $PQSAVEPAR2.4.2. $PQRESTOREPAR

3 Messages3.1. NMEA Standard Messages3.1.1. List of NMEA Standard Messages3.1.2. NMEA Standard Messages Specification3.1.2.1. $--RMC3.1.2.2. $--GGA3.1.2.3. $--GLL3.1.2.4. $--GSV3.1.2.5. $--GSA3.1.2.6. $--VTG

4 Default Configurations5 Appendix A References

lc79d (a) gnss protocol specification · 2019. 12. 27. · nmea messages supported by the module....

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