Hi,
I've recently purchased an APM2 with a builtin GPS. It is mounted in a HK Turnigy Talon v2 quadcopter. I've had a few flight in stabilize mode and it works well but I cannot get a GPS fix. The blue leds on the dautherboard and on the main board are both blinking. I have currently no telemetry but when I connect with an USB cable to a laptop and getting outside, I can see in MissionPlanner that it sometimes gets 1 sat and very rarely 2. I tried for tens of minutes (maybe 30 or more minutes) without a better result. I get no GPS fix neither with the APM being powered by a lipo nor by the USB cable. I've tried in different locations with no better results. My car's GPS in the same locations gets a GPS lock in one minute.
What could I do ?
Best Regards,
Remi
Replies
...Not sure what the go is, as I have been using GPS devices for many years, I developed a tracking system with Franson many years ago and use SANav devices, and leadtek, and even Nokia...all have fantastic GPS pickup, but the Mediatek onboard seems a little insufferable.
I have seen so many suggestions of "unplug your receiver" and remove your ESC, etc...but if these are all solutions by the time I'm finished the only thing that will be in the UAV will be the APM itself - it can't be a solution to remove all other electronic equipment just to get the GPS to pick up more than 2 sats.
OK - a bit of ranting there, but then that being said early on in the evening (I'm guessing it was before the clouds rolled in.) I did have good sats (6 I think.) and was getting to within 3-4 metres without much drift...interestingly right before I got nothing I started to see my plane icon in mission planner slowly creaping north until it was over the back fence of the neighbour across the road. Althogether not to bad really...But I suppose the reason I am posting this is...HAS ANYONE...managed to increase the pickup ability of the Mediatek GPS - whether onboard or offboard by changing the antenna...
What I've seen is every manufacturer is SO very proud that their GPS is smallest on the market with small Ceramo-helical GPS Patch antennas smaller than my thumb. But the reality is I am not THAT void of space that I can't afford a few more mm for a bigger antenna. SO my question really is, is there any merit or harm in creating an external antenna to attach to the GPS module...and if so does anyone have any plans/calculations like iBcrazy's CL and SP antennas...
Hi,
I think I solved the problem. I mounted my receiver on an arm like Mike's, added a ferrite coil on the APM to receiver power cable, added an ubec to power the APM and I had a flight with a GPS 3d fix. I had to add an ubec because the GPS was still confused with the APM being powered by an ESC (it was working ok while being USB powered but no fix while being powered by the ESC).
Thanks again.
Remi
What other equipment do you have attached to or near the APM? In some other cases like this in the past, I've seen RF or magnetic interference preventing the GPS from locking onto enough satellites. As a test, unplug everything else from the APM, only use power (ch3) and don't even plug in the motor, and take it outside, with clear access to the sky. Make sure you don't have the RX, Telemetry, or anything else near it. Don't run the throttle, as the ESC will create a magnetic field. Make sure it is not installed inside a carbon fiber frame. Just carry the APM2, an ESC for power, and the battery outside and see if the GPS gets a lock. If so, it will suggest what the issue is. Then you can add the devices back, one at a time, until you see it have problems. Then you will know what to move or fix.