dGPS problem in Thailand


Hi Dexter

I have a dGPS but it looks like not work well. It displays on blick’s screen as below, when running this code dexterind-gps-test1.c
Umm…, I’m using it in Thailand Asia which that should not be a concern. Right…

   DGPS  Test 1 

UTC is 1200XX
Lon: 0
Lat: 0

Link Stat : [down]

Any advises,



Hey Bundit,
A few standard questions:

  • Does the dGPS blink when you turn the power on your NXT or when you plug it in?
  • When you see 1200xx, does the xx increment (increase)?

If that works, the board itself is working and it’s getting data from the GPS. Most likely it will take some time to get some information from the GPS satellites. When the sensor is first run, it needs to download an almanac and get coordinates for the first time. It can take 15-20 minutes in open skies to get this data and get a satellite link.


-Yes, It blinks abit and off light, when plug it in port.
-With 1200xx, there is changing of number xx during tests. I will try it again to see that number is increasing.



It should be increasing. It sounds like it’s working if you’re getting a number like that. If it’s not, one more thing to try: add a pause of at least 1 second between the times that it polls the sensor.


I just have a chance to try again.

The number was keep increasing until 120925, then software aborted and a brick turns off.
I tried both RobotC code and NXC. They result the same.

I set 1.5 seconds between the times that it polls the sensor.

Any advises ?



The Brick turns off? If the Brick is restarting, I would look at putting a better set of batteries in the NXT brick. Is it possible to put a fresh, new set of batteries in the NXT?


I’ve just a chance to test it again, when clear sky.
Yes, sensor works with a new set of batteries like you mentioned.

Thank you,