Teseo GNSS module - no fix

[JJRR]

Hi,

I have own design with Teseo GNSS LV3R module. It is connected to STM32L071. After power up I just set Reset pin to low for 10 ms and then I keep it in high level. Unfortunatelly even after 3 hours under open air ( without clouds and nearby buildings) I still can no read any gps position. The NMEA messages goes but they are almost empty...

My design is inclosed. Did I missed anything? What could I make wrong?

I tried it with and without the LNA - the result was same.

Thank you very much for advices.

Jan.

[GLASS]

Double check, power delivered to antena if it is an active one...

And Rf design vs routing.​

Is it an allways on design? Vs Vbatt routing.

A gps or gnss need to backup ephemerid, otherwise you make systematic coldstart (12.5 minutes in bad case).

​It's a generic advice, i'm not using Teseo at this time.​..

[JJRR]

Thanks for reply:

Power is OK, RF design and routing looks ok for me. Antena is passive. I have common power for vBat and Vcc.

Now I I don't know what to do...

[GLASS]

Hi. I'm not sure that your actual routing is OK for very high frequency​ .

I'd give a look to ​UM2231 guide. ST is explicit in chapter 8 and 9.

If re routing,​ consider saw filter in rf path, power decoupling lna. Avoid poor ground. Take care of parasitic self of via. Rf path must be routed with care to match impedance... be sure to have good ground all around rf path and keep away other signal or power to avoid bad coupling.

[Eleon BORLINI]

Hi @Community member​ ,

did you make some progresses in your application?

-Eleon

[JJRR]

Hi, I edited the PCB (according to the ST notes) and now I am waiting for production of samples. Then I will try it.

Thanks.