Hi,I got a ublox 5 GPS unit the other week and I've been trying to get it work for days, but to no avail.I was wondering if anyone could give me some tips or advice on what I am doing wrong.I am using the Sparkfun breakout (GS407) to connect the u-blox to a FTDI cable (Thanks MarkH). and powering it with clean 3.3v.I used the u-center software to connect to the device. I get the following messages from the GPS unit (all the time):??:??:?? $GPRMC,,V,,,,,,,,,,N*53??:??:?? $GPVTG,,,,,,,,,N*30??:??:?? $GPGGA,,,,,,0,00,99.99,,,,,,*48??:??:?? $GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*30??:??:?? $GPGSV,1,1,00*79??:??:?? $GPGLL,,,,,,V,N*64But this is all I get.These are the things I have tried:- Flashed the module with the latest firmware- Powered the 3.3v from a Fez Panda (micro controller)- Powered the 3.3v from a 3.3v voltage regulator- Added all the filtering capacitors they suggested- Reset the module back to default settings- Stood outside with it for 20 mins (clear sky)- Connected the BATT pin to 3.3v- Check the current it is using: 70mA to 110mA- Confirmed all GND points are grounded- I updated the almanac for the next few daysI have heard that the module requires a good clean 3.3v, so I tried all the options I could. I noticed a voltage drop of 3.1v across the module when it is running, even though I supplied it with 3.3v - Not sure if this helps.I haven't powered it with anything but 3.3v, so I'm quite certain I haven't fried it.From what I can see, the Antenna is securely on with 4 big blobs of solder.I tried moving it around when I was outside, but still no satelittes.I tried another GPS module I had, and satellites popped up within a few seconds.Some thoughts:- Perhaps the connection to the antenna is faulty - but I can't check that as it is all enclosed.- Perhaps I'm still not getting the voltage right - It's strange that the voltage drop is only 3.1v instead of 3.3.- Perhaps it's got something to do with me being in the southern hemisphere, whereas the module comes from the North.Any suggestions would be really appreciated. Thanks.
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GPS receivers need a low impedance supply with very little noise. I design them for living. The dsp core draws
Very high narrow pulse width peaks. You need a big cap right near the Gps power pin. 10uf minimum. If it shares the supply
You can run into trouble with other systems inducing noise. A larger cap and an inductor helps. A resistors over 1 ohm in line with no large cap after it will be a problem as well. Jammers such as switch mode psu are main culprits for not receivg sats due to jamming. This can helped by screening the digital AP unit and any psu.
I have a Ublox that I dropped and snapped the antenna right off. It was wobbly to begin with due to bad soldering(not all the way don the board) . I repaired the plastic with" JB weld", reattached to board with silicone and let cure. Then I re-soldered it and now it works fine. It's very small work I used a magnifier , my reading glasses with a loupe. You must be very still.
If this is the ublox 5 from the sparkfun page with the helical antenna, my experience is that 3.3v will do a great job at powering the compute engine, but you need a good solid 4.8 to 4.9v (or more) to get the antenna cranked up and seeing satellites. Jordy's quote was that the gps needs to be "well powered". I also found heat to be an issue (I think). When I had my gps wrapped up in bubble wrap, I had a lot of trouble seeing much of anything reliably ... especially on hot days. Once I ditched the bubble wrap and just 2-sided taped it to the inside of my fuselage (hanging out a bit off a square block of foam) it's worked pretty well since then. On the hot days this summer I tried to keep the airplane in the shade when it wasn't flying just to avoid excessive heat build up in the cabin.
Also, hook it up to the u-center software that you can download for free from the ublox web site, that will show you a lot more (or at least show you in a much more readable form) exactly what the gps is doing.
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Very high narrow pulse width peaks. You need a big cap right near the Gps power pin. 10uf minimum. If it shares the supply
You can run into trouble with other systems inducing noise. A larger cap and an inductor helps. A resistors over 1 ohm in line with no large cap after it will be a problem as well. Jammers such as switch mode psu are main culprits for not receivg sats due to jamming. This can helped by screening the digital AP unit and any psu.
i'm having very similar problems!
Also, hook it up to the u-center software that you can download for free from the ublox web site, that will show you a lot more (or at least show you in a much more readable form) exactly what the gps is doing.