Locosys LS20031 - no fix

GPS/GNSS Development Boards
1

Greetings, was hoping I might beg to query the giant brain trust here. :slight_smile: I just got an LS20031 GPS and carefully connected it to my mbed mcu per the GPS datasheet, checking Vcc prior to hooking up to ensure 3.3V etc.

I am getting output at 57600 baud, no problem, timestamp incrementing by 200ms and everything:

$GPGGA,002557.836,0,0,M,M,*40

$GPGLL,002557.836,V,N*72

$GPGSA,A,1,*1E

$GPGSV,1,1,00*79

$GPRMC,002557.836,V,0.00,0.00,060180,N*4A

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

The problem lies in the fact that the GPS never gets a fix, red LED never blinks at 1Hz per datasheet. The LED blinks once on powerup, then never again.

Have tried outside, inside, near windows, etc. I’ve given it 10-30 minutes to get a fix (I thought it has a 35 seconds TFF… not minutes or hours :D)

I wonder if I got a defective unit or am I missing something obvious once again? :slight_smile:

Any other ideas?

Thanks in advance,

Michael

2

crickets<<

:smiley:

3

I was able to communicate with and configure the device with MiniGPS (changed update rate, etc)

Tried cold restarts, cold then hot restarts. Always times out.

Got in touch with SFE tech support; they asked me to send it in for testing and if it is broken, they’ll replace it. Yay, SFE!

So will send in shortly.

4

Followup: after some kind help from SFE technical support I mailed in the GPS unit which was found to be defective as a new one was sent back to me.

I had trouble with the new one… until I removed it from the solderless breadboard, and connected using wires keeping it away from the breadboard and the mbed MCU. I got a fix very quickly and strongly. The GPS works beautifully occasionally getting a fix from my basement… !! Hot start fix takes seconds and the GPS seems very sensitive so far.

Thanks SFE!