Neo-6m GPS - which NMEA sentences required?

Projects Networking, Protocols, and Devices
1

Hi:

I am new to Arduino and wanting to build an LCD GPS clock for a first project.
I have several Neo-6M modules. I was reading a tutorial about doing this
(Ref: http://w8bh.net/avr/clock2.pdf )
that warns of possible character loss and time accuracy loss if you let the GPS module
send too many sentences, and at a software serial low baud rate, the arduino
may not be able to receive and process ALL of it, each second, before the next cycle
starts. I want to avoid buffer overflow and loss of accuracy in the program.
So it seems like a good idea to configure the GPS module to only output the NMEA
sentences that are needed by the GPS library?

The U-Center software from UBlox for the Neo-6m will let you turn sentences on
and off, so you can control how many sentences are output from the GPS, for the
little arduino to choke on, um, er, READ().

QUESTION: I was looking at the TinyGPS library docs and can't find mention of
which NMEA sentences it needs as a minimum. I also tried google.
Does anyone know how many of the NMEA sentences the GPS needs to output, in
order for the library to still work?

Is it just $GPRMC and $GPGGA, as the static example shows for TinyGPS, or does
the library need to see other sentences on the serial port?

Thanks,

Neal

2

RMC or GGA is all you need for a clock.

TinyGPS doesn't "need" any sentences, it simply filters and interprets certain of them. You don't need TinyGPS either, the Arduino is plenty fast enough to get the time out of either of the RMC or GGA sentences.

3

Nealix:
QUESTION: I was looking at the TinyGPS library docs and can't find mention of
which NMEA sentences it needs as a minimum.

There is no particular need for the documentation to say which sentences its using but if you read the actual code in the library, tinygps.cpp, you will see its fairly clear it only references GPGGA and GPRMC sentences.