Template:UART GPS NEO-7M User Manual

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Features

  • NEO-7M-Conboard, with high-gain active antenna
  • IPXinterface, for connecting different active antennas
  • Chargeablebackup battery, keeps the ephemeris data when power down, supports hot starts

Parameters

Receiver type: 56 channels, GPS L1(1575.42Mhz) C/A code, SBAS:WAAS/EGNOS/MSAS
Horizontal position accuracy: 2.5mCEP (SBAS:2.0mCEP)
Navigation update rate: 10Hz maximum (1HZ default)
Capture time: Cool start: 27s (fastest);Hot start: 1s
Tracking & Navigation sensitivity:
Communication protocol: NMEA(default)/UBX Binary
Serial baud rate: 4800, 9600(default), 19200, 38400, 57600, 115200, 230400
Operating temperature:
Operating voltage: 2.7V~5.0V(power supply input via VCC)
Operating current: 35mA
TXD/RXD impedance: 510Ohms

Applications

Thismodule can be applied to navigator, aircraft positioning, etc.

Hardware

  • Acomputer with Windows XP/Win7/Win8 OS;
  • An USBto TTL serial module, such as FT232, PL2303, CP2102, etc. If there is a nativeserial port in the computer, a DB9 to TTL serial module may be used;
  • A UARTGPS NEO-7M-C module.


How to use

  • Connectthe UART GPS NEO-7M-C module to a serial module. FT232 is applied as the serialmodule in this document.

The connection between the GPS module and the serial moduleis listed as the table below.

UART GPS NEO-7M-C module pins Serial module pins
VCC 3.3V/5V
GND GND
TXD RX
RXD TX
PSS*
  • PPS should be connected to the clock pulse output (CPOUT) of a MCU. However, this pin is unconnected, in the case that the GPS module is connected to a computer.
  • Connectthe serial module to the computer.
  • Startthe serial debugging assistant, and set the serial port as below:
    • Selectthe corresponding serial port in the PortNooption. In this example, COM8 is selected.
    • Baudrate: 9600(default).
    • 8 databits, 1 stop bit, no parity and no flow control.
  • Afterfinishing the settings, you can see the serial debugging assistant will showmany data in its window, as the figure shows below.

UART-GPS-NEO-7M-User-Manual-1.png

The data shown in the figure abovemeans that the connection is established successfully, but it is unable toperform positioning.

In this case, please place the GPSmodule to the balcony or near the window, or outdoors for testing, because GPSis less stable in searching signal indoors.

  • Afterwaiting for a while, if the serial debugging assistant lists similar data in itswindow as the figure shows below, it means GPS has performed positioning. Andyou can see that the LED on the module, which remains on when GPS is unable toperform the positioning, is flickering now.

UART-GPS-NEO-7M-User-Manual-2.png

Notice: For its first positioningafter cold starts, GPS module normally takes 1-3 minutes to finishing thispositioning successfully in the open air with a good weather. So, please bepatient. Moreover, if there is a bad weather, it may take more time forpositioning, or even unable to perform positioning sometimes.

  • Installsoftware\u-centersetup-7.0.2.1\u-centerSetup-7.0.2.1.exe (please ensure you computer is connected to Internet).

Start the software, u-center, and you can see the interface as the figure showsbelow.

UART-GPS-NEO-7M-User-Manual-3.png

  • Click Receiver menu, and select Port option to configure the actual serialport number and Baud rate: 9600.

Click thebutton

UART-GPS-NEO-7M-User-Manual-4.png

toconnect to the UARTGPS NEO-7M-C module.

u-center will show theinformation as below:

UART-GPS-NEO-7M-User-Manual-5.jpg

  • Install aplug-in, GoogleEarthPluginSetup.exe, for a better view. After finishing theinstallation, select Google Earth under the Viewmenu in the u-center.

Notes: There may be some differencesbetween the reality and the result shown by Google Earth, because of GPS staticdrift.

Appendix

  • After a successful positioning, you will receive a lot ofinformation, as the figure shows below.

UART-GPS-NEO-7M-User-Manual-6.jpg

What are the meanings ofthe information?

We will illustrate theseinformation with an example of $GPRMC,030742.00,A,2232.73830,N,11404.58520,E,0.356,,070314,,,A*77

  • Firstly, openthe document chip PDF\NMEA0183.pdf

Secondly, findthe relative explanations of GPRMC, as the figure shows.

UART-GPS-NEO-7M-User-Manual-7.jpg

  • The meaningof each field in

$GPRMC,030742.00,A,2232.73830,N,11404.58520,E,0.356,,070314,,,A*77is listed as below.

030742.00 UTC time; since the test location is Eastern eight zones, the actual time should be 03+8=11(hour):07(minute):42(second)
A Position state; it indicates valid
2232.73830 Latitude value
N The Northern Hemisphere
11404.58520 Longitude value
E The Eastern Hemisphere
0.356 Ground speed; 0.356knot (1knot =1 nautical mile per hour,which is equivalent to 0.5m per second)
070314 UTC date; it indicates 7th March, 2014
A Mode indication; it is in AssistNow Autonomous mode
77 Checksum; it is the result of XOR operation on the ASCII code of all the charactersbetween $ and *
  • For more detail instructions about u-center, please refer to GPS Datasheets.