This document provides NMEA command manual for u-blox, Fastrax
IT500 series GPS/GNSS modules based on MediaTek chipset. This
NMEA command manual serves as a reference tool.
NMEA Manual based on MediaTek chipset - Manual
Document Information
Title NMEA Manual based on MediaTek chipset
Subtitle For u-blox, Fastrax IT500 series GPS/GNSS modules
Document type Manual
Document number FTX-HW-13002-A
Document status Preliminary
Document status information
Objective
Specification
Advance
Information
Preliminary
This document contains target values. Revised and supplementary data will be published
later.
This document contains data based on early testing. Revised and supplementary data will
be published later.
This document contains data from product verification. Revised and supplementary data
may be published later.
Released This document contains the final product specification.
2.1 PMTK000 TEST ................................................................................................................................... 10
xx=degrees; mm=minutes; dddd=decimal part of minutes
1 NMEA default output messages
IT500 series receivers support standard NMEA0183 messages.
In the default configuration, output messages are GGA, RMC, GSV and GSA messages. The receiver can be
configured to have a user defined set of output messages, by command PMTK314 as described in chapter 2.12.
Output messages are utilized in Fastrax Workbench 5 to visualize the GPS/GNSS data. Default output messages
cover most of the applications.
1.1 GGA - Global Positioning System Fix Data
Time, position and fix related data for a GPS receiver.
hh=hours; mm=minutes; ss=seconds; dd=decimal part of seconds
<N/S> Character denoting either N=North or S=South.
yyymm.dddd Longitude coordinate.
<E/W> Character denoting either E=East or W=West.
v Fix valid indicator
ss Number of satellites used in position fix, 00-12. Notice: Fixed length field of two letters.
d.d HDOP - Horizontal Dilution Of Precision.
h.h Altitude (mean-sea-level, geoid)
M Letter M.
g.g Difference between the WGS-84 reference ellipsoid surface and the mean-sea-level altitude.
M Letter M.
a.a xxxx -
yyy=degrees; mm=minutes; dddd=decimal part of minutes
<N|S> Character denoting either N=North or S=South.
yyymm.dddd Longitude coordinate.
<E|W> Character denoting either E=East or W=West.
UTC time of the fix.
Status indicator.
xx=degrees; mm=minutes; dddd=decimal part of minutes
yyy=degrees; mm=minutes; dddd=decimal part of minutes
ddmmyy
M
UTC Date of the fix.
Mode indicator
1.6 GSV - Satellites in view
Number of satellites in view, satellite ID (PRN) numbers, elevation, azimuth and SNR value. The information for
four satellites is a maximum per one message, additional messages up to maximum of eight are sent if needed.
The satellites are in PRN number order.
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NMEA Manual based on MediaTek chipset - Manual
n
Total number of messages, 1 to 9
m
Message number, 1 to 9
ss
Total number of satellites in view
xx
Satellite ID (PRN) number
ee
Satellite elevation, degrees 90 max
aaa
Satellite azimuth, degrees True, 000 to 359
be on the visible sky but it isn't being tracked.
Type
Description
A = Automatic, allowed to automatically switch 2D/3D.
3 = 3D
xx
ID (PRN) numbers of GPS satellites used in solution
p.p
PDOP
h.h
HDOP
Message starting with “$GNGSV” will be output in IT530M default mode, including both GPS and
UTC time in hours, minutes, seconds and fractions of a second.
dd
UTC day of month
mm
UTC month
yyyy
UTC year
xx
Local zone hours. Not implemented
yy
Local zone minutes. Not implemented
1.8 VTG – Course Over Ground and Ground Speed
Course and speed.
Example:
$GPVTG,0.00,T,,M,0.00,N,0.00,K,A*3D
Format:
$GPVTG,h.hh,T,m.m,M,s.ss,N,s.ss,K,M*hh<CR><LF>
Type Description
M
Mode indicator.
1.9 ZDA – Time and Date
Current UTC time and date.
Example:
$GPZDA,071850.000,31,08,2011,,*55
Format:
$GPZDA,hhmmss.ddd,dd,mm,yyyy,xx,yy*hh
Type Description
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NMEA Manual based on MediaTek chipset - Manual
2 NMEA commands
NMEA commands are used to change or query settings of the module.
Command Length:
The maximum length of each packet is restricted to 255 bytes.
Command Contents:
Preamble: One byte character. ‘$’
NMEA ID: This will identify for the NMEA parser that it will receive commands for MediaTek.
Four bytes character string. “PMTK”
Command Number: Three-byte character string.
An identifier, from “000” to “999”, is used to tell the decoder how to decode the command.
DataField:
The DataField has a variable length depending on the command type.
A comma symbol ‘,’ must be inserted before each data field to help the decoder process the DataField.
*: 1 byte character.
The star symbol is used to mark the end of DataField.
CHK1, CHK2: Two-byte character string.
CHK1 and CHK2 are the checksum of the data between Preamble and ‘*’.
CR, LF: Two bytes binary data.
The two bytes are used to identify the end of a command.
Sample Command:
$PMTK000*32<CR><LF>
You can use your preferred terminal emulator to enter commands. For example, you can use TeraTerm,
whichcan be downloaded from here:
Remember to set the CR+LF for sending the command from the terminal program.
Other possible terminal emulators to use include Putty and HyperTerminal.
FTX-HW-13002-A Preliminary Page 9 of 39
Figure 2: HyperTerminal setup
NMEA Manual based on MediaTek chipset - Manual
2.1 PMTK000 TEST
Command purpose:
Test the communication between the receiver and host.
Command number: 000
DataField: None
Example:
$PMTK000*32<CR><LF>
Reply: see next chapter.
2.2 PMTK001 ACK
Command purpose:
Acknowledge a PMTK000 command.
Command number: 001
DataField:
PMTK001,Cmd,Flag
Cmd: The command / packet type to be acknowledged.
Flag: 0 = Invalid command / packet.
1 = Unsupported command / packet type
2 = Valid command / packet, but action failed
3 = Valid command / packet, and action succeeded
Example:
$PMTK001,604,3*32<CR><LF>
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NMEA Manual based on MediaTek chipset - Manual
2.3 PMTK010 Startup message
Command purpose:
Output system message.
Command number: 010
DataField:
Msg: The system message.
‘0’: UNKNOWN
‘1’: STARTUP
‘2’: Notification for the host aiding EPO
‘3’: Notification for the transition to Normal mode is successfully done
Message ‘2’ and ‘3’ apply only for MT333X based receivers IT530, IT530M, UC530 and UC530M.
Example:
$PMTK010,001*2E<CR><LF>
2.4 PMTK011 Output System Text
Command purpose:
Output system text message.
Command number: 011
DataField:
Message of this is MTK GPS
Example:
$PMTK011,MTKGPS*08 <CR><LF>
2.5 PMTK101 CMD HOT START
Command purpose:
Hot restart: Use all available data in the NV Store.
Command number: 101
DataField: None
Example:
$PMTK101*32<CR><LF>
2.6 PMTK102 CMD WARM START
Command purpose:
Warm restart: Don't use ephemeris at re-start.
Command number: 102
DataField: None
Example:
$PMTK102*31<CR><LF>
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NMEA Manual based on MediaTek chipset - Manual
2.7 PMTK103 CMD COLD START
Command purpose:
Cold restart: Don't use time, position, almanacs and ephemeris data at re-start.
Command number: 103
DataField: None
Example:
$PMTK103*30<CR><LF>
2.8 PMTK104 CMD FULL COLD START
Command purpose:
Full cold restart: It’s essentially a cold restart, but additionally it clears system/user configurations at re-start. That
is, reset the receiver to the factory status.
Command number: 104
DataField: None
Example:
$PMTK104*37<CR><LF>
2.9 PMTK120 CLEAR FLASH AID
Command purpose:
Erase aiding data stored in the flash memory.
Command number: 120
DataField: none
Example:
$PMTK120*31<CR><LF>
Reply:
$PMTK001,120,3*33
This message applies only for MT333X based receivers IT530, IT530M, UC530 and UC530M.
2.10 PMTK127 CLEAR EPO FILE
Command purpose:
Clear predicted ephemeris file (EPO) from flash memory.
Command number: 127
DataField: ‘0’ Clear
Example:
$PMTK127,0*2A<CR><LF>
Reply:
$PMTK001,127,3*34
This message applies only for MT333X based receivers IT530, IT530M, UC530 and UC530M.
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