How to tell if GPS is working or not

I just bought a LS20033 5Hz update GPS and connected it up to my Arduino Mega in hopes to use it on a UGV at some point in the near future. I connected power to 3.3V and the GPS Tx to the serial Rx (pin 0) on the Mega and left it by the window for about 20 minutes and didn’t get a thing. I tried using an Eagle Tree Systems GPS and was able to see data in the serial monitor without issues but couldn’t get anything out of this LS20033. I tried baud rates of 38400, 57600, 9600 and didn’t get a thing on the serial monitor. I followed the instructions from http://www.sparkfun.com/tutorials/176 and couldn’t get anything to come up. My question is, how do you know if a GPS is bad or not? I don’t have an o-scope so I can’t look at anything coming out of it but I have no way of knowing if I even have a lock. Any ideas on what could be wrong or where to go to try and troubleshoot this problem?

You should have a1pps pulse coming out of it. An LED on the pin will show if it is working.

Hi,

There is a ‘GPS LED’ signal on pin #5 that is low for no lock, and blips high once per second for once a position fix has been determined. The datasheet is not clear on this, but I’d probably put a 300 ohm resistor in series with the LED to start, and see if anything happens after a while. If not, you might try reducing/removing the resistor.

A scope would tell the story immediately if you have one. For GPS module work a TTL-to-RS232 converter can be very handy as it would allow you to connect the module directly to your PC, and see the data output on a terminal program like Hyperterminal.

One other thing, the default baud rate for the module appears to be 9600 baud.

Good luck!

John

Make sure you have:

3.3v on the (Pin 1 - Vcc pin).

Ground to (Pin 2 - Ground).

Rxi (Mega) to (Pin 3 - TTL Tx)

You might need 3.3v on (Pin 6 - Battery backup supply)