PMOD GPS receiver cannot connect to the satelite

[kmbm]

Hi,

I have pmod gps receiver, and I connected it to my zybo board using pmod. I would like to get data from it but it can't connect to the satelite. I have petalinux on arm processor so I execute cat < /dev/ttyPS1 and I receive the gps module output but fields like position etc. are empty. The green led is still blinking. I am waiting about 30minutes and I still have the same problem. What have I do to run it correctly

[jpeyron]

Hi @kmbm,

Have you made a vivado/sdk project using the PmodGPS without the embedded Linux to make sure that you have the hardware done correctly. Where are you trying to use the PmodGP?. Are you outside? Are you in a building if so are you near a window? 

thank you,

Jon

[kmbm]

Hi @jpeyron,

Thanks for your response. My hardware configuration is rather OK. Uart works fine ( I have checked it with logic analyzer) and I can read the response from GPS, but some fields are not set and the status led is blinking. Here is the sample response which I get. 

$GPGGA,000222.037,,,,,0,0,,,M,,M,,*4E

$GPGSA,A,1,,,,,,,,,,,,,,,*1E

$GPRMC,000222.037,V,,,,,0.00,0.00,060180,,,N*44

$GPVTG,0.00,T,,M,0.00,N,0.00,K,N*32

$GPGGA,000222.037,,,,,0,0,,,M,,M,,*4E

I'm in the building but near the window. Gps in my mobile phone works fine

[D@n]

@kmbm,

If the light is blinking, you don't have any signals.  You might want to place it even closer to the window, and then perhaps let it wait for a while.  Cold starts can take a bit.  Indeed, it can take 12+ minutes to download the full GPS information from the satellites.  (Many modern receivers have a battery to maintain that information, PModGPS does not.)

Dan

[kmbm]

The module is really near the window. Now I'm waiting over 3 hours and I still don't have any signal

[D@n]

@kmbm,

Does the window have a good view of the sky?  Or does it open into an urban canyon?

Dan

 

[kmbm]

I've tried to put the module outside. I was waiting about hour but it didn't help

[D@n]

@kmbm,

Cloudy day?  Urban canyon?

Dan

[kmbm]

sunny day, urban canyon

[D@n]

@kmbm,

Yeah, okay ... I hate to ask this but ... do you have access to a park or a roof top that you can try it on?

Dan

P.S.  I am not Digilent staff.  However, I did study GPS for several years, so ... I'm somewhat familiar with both how it works and when it fails.  So far, your hardware is acting like it's working, just ... not like it's getting any signal.