NEO-6M GPS module - data missing

Hi. I was trying to get some data from the NEO-6M GPS module. What I did was connecting the GPS module to a FTDI module and view the data on the serial monitor. Initially, many of the data is missing and some people were saying that the battery on the module needs to be charged in order for the module to work properly. So, I leave it on the table for some time (and power it using 5V from my laptop) and it starts showing the time. However, the longitude and latitude was still missing. I already test it in an open space but still not getting the longitude and latitude. What could be the problem? (The LED on the module is not blinking)

The GPGLL line was something like this: $GPGLL,,,,,162119.00,V,N*46

Also, The module become a little bit warm after 1 hour, is that normal?

And those people are confused.

You GPS does not need a charged battery, or any battery to work properly.

The GPGLL line was something like this: $GPGLL,,,,,162119.00,V,N*46

So the GPS is not getting a fix, is it outdoors with a good view of the sky and has a decent working antenna ?

Also, The module become a little bit warm after 1 hour, is that normal?

Sort of, those Neo-6Ms use a heap of power, maybe 200mw, so expect them to warm up a bit.

And it would help a great deal if you revealed all the output the GPS is producing over a few seconds. There will be clues in there as to the problem and this output must be when the GPS is outdoors etc ........

If not outdoors, with a clear view of the sky, then that is the problem. Satellite signals are very weak, and generally don't penetrate buildings. However, GPS units will sometimes work near a window.

I forgot to mention, after I leave it on table for some time, I bring it near to a window and it starts showing the time. So, the data is still missing even if I bring it close to the window.

Take it outside. GPS devices struggle indoors.

$GPVTG,,,,,,,,,N*30
$GPGGA,,,,,,0,00,99.99,,,,,,*48
$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*30
$GPGSV,4,1,13,02,,,19,04,,,10,05,,,17,06,,,10*75
$GPGSV,4,2,13,11,,,20,12,,,21,13,,,21,14,,,20*79
$GPGSV,4,3,13,15,,,20,18,,,21,19,,,13,22,,,21*79
$GPGSV,4,4,13,23,,,19*72
$GPGLL,,,,,,V,N*64

The output is something like this when tested in outdoor. Note that the data for GPGLL is void...

Hello pauline.

Well done on going so far on yr own efforts.

Can I ask what software you are using to monitor the sentences?

I experience similar problem many times. It goes away eventually without explanation. Frustrating.

I don't believe it's as simple as having a clear skyview, although that is important.

It's useful to have a reference to explain NMEA sentences:
http://aprs.gids.nl/nmea/#gll

Hi. I am using Arduino serial monitor to display the output.

I don't know how deeply you wish to go into analysing the GPS output. The software from u-blox (called u-center) allows you to examine the output in great detail and in graphical displays. Far more informative than the IDE.

Your GSV sentences say the device is "seeing" 13 sats. Then it lists each sat id and its signal strength: (02,19) (04,10) (05,17) and so on.

The empty fields are where the azimuth & elevation of the sat will go when they are available. U-blox describes these signals as "seen" but "not useable for navigational purposes". I wonder if these are not genuinely "seen" but are just being scanned for. There's a lot of black box character about u-blox algorithms from the user's point of view.

When you receive just one useable sat signal, it gives the date & time (all the sats send date & time). So that's the first sign you'll get that things are progressing.

What type of antenna is it? Is it a screwed connection or a tiny press fit socket?

You'll get there.

'Something like this' ?

Does that mean the output posted was actually indoors ?

if so then its of very little help, need to see the data from when the GPS is outdoors with a good view of the sky.

The comments about being outdoors are correct. I have a neo6m and it gave the same issues indoors.
In my experience, you can also improve its reception with a ground plane. Think of it like a satellite dish.
In my project (on a motorbike), I used a 30mmx30mm piece of steel sheet. But it doesn't really matter what metal you use (but in essence the bigger the better). You could (carefully so you don't injure yourself) cut a small square from a food or drink tin. As I say, be careful of sharp edges - for safety you should fold over all the way around by a few mm, and then gently hammer flat. The folded edge will also add rigidity to the material also.
In my case, the ground of the antenna was touching the ground plane.
In short - outside is good. Outside with a ground plane is much better.

My Neo 6Ms are not producing any sat data. I need to understand why they have gone from working well to not producing any data.

A clear skyview is the easiest factor to make right and be certain you have it right. You just go to a place that has a 360 degree unobstructed skyview.

Can you tell me please -- what is your GPS's behaviour when it has a partially obstructed skyview? I would expect reduced sat numbers and signal strengths, not a complete blackout. Thank you if you can do that.