Iris+ won't arm

I am using a 3DR Iris+ with Mission Planner 1.3.37 and APM Copter 3.3.3.
I am not able to get it to arm. In Mission Planner I get a message of GPS Horiz 1.0 and Yellow blinking light. The light will never go Green showing GPS lock but my controller says I have 8 Satellites Locked. I have done all of the calibrations also.

Also, I cannot get it to link to the Tower App on my phone. It will not connect.

I have read everything I can find and have not been able to get it to work. I show a HDOP of 1.2. Does anyone know what I need to check?

You might have accidentally put it in ESC calibration mode (powering on with the throttle in high position).

Yellow flashing is bad and it should turn blue when system checks complete. Green when it has the required satellites. If the copter is in a GPS mode it will stay yellow until it has the required number of GPS satellites. In Alt Hold it should be as described above.

If you have it connected to Mission Planner look on the last tab on the HUB screen which says Messages and it should indicate what it doesn’t like.


Thanks guys, by reading the messages it gave me a clue. After I changed my FS_THR_Value from 982 to 925 it armed after about 4-5 minutes of collecting GPS data.

I tested it a couple of times and it seems to be working, but I still a cannot get it to connect to the Tower App on my phone. I removed the apps and reinstalled them but no success. Anybody know anything about Tower?

I know when I plug the radio into my tablet it launches the 3DR services app. If this service is not running it will say so.