APM 2.6 GPS & Compass going crazy

Hello members,

I need some help with my first Multicopter ever for which I am using an APM 2.6 board with external compass & GPS.

My GPS & Compass just seems to be going crazy. I have tried calibrating the compass several times but still i keep getting the PreArm: compass offset too high error & crazy offset parameters after caliberating. Then i also get BAD GPS Health error whereas the GPS shows full 3d lock & on the mission planner it shows that my copter is flying to several places but infact it is standing at one place.

Please people i am in desperate need of some advise, i will deeply appreciate your effort to help me out, Thanks.

Will some one please advise where i can download a a working “Advanced Param List” for 800mm Hexacopter?

@comet,
How are you powering your APM during compass calibration? Are you using the USB port or the telemetry radios?
If you are not using a powered USB port to power the APM and external components. then I suggest that you try using one. Many PCs/Laptops cannot supply enough current for a full up APM. Also, you might try another USB cable if you have one available.
Regards,
TCIII GM

@TCIII
Thanks a lot TCIII for your reply,
I am powering my APM from an external power, by this i mean my power input is 12v & the power is stepped down using 7806 (6V) regulator which i am supplying to Output port of APM with JP1 closed, I am using Telemetry for communication with the PC.
Best Regards,
Comet.

6V is the abs max voltage using the JP1, if for some reason the regulator you are using is giving a little bit more than that can damage the board.

copter.ardupilot.com/wiki/common … _Installed

You shoud check your 3.3V regulator:
youtube.com/watch?feature=pl … q6jjha5rgU

Putting 6V into the board is a bad idea.

copter.ardupilot.com/wiki/common … _Installed

You may have already damaged the board and have caused the erroneous readings

The regulators output without load is 5.9 Volt & when supplied to APM it is 5.5 volt on the 5 volt rail I have been monitoring it time to time around APM circuitry. Just Checked the 3.3v regulator, it is Fine (input= 5.5v & Output= 3.4v).

Even if the voltage goes above 6V, can anybody please explain what is the D4 (The 6V diode above I2C port) for?

Hi, Seems like i had a flaw in my setup, there was a bolt & nut very close to my Compass which were responsible for the crazy high offsets, now with the new setup things look good with the compass, calibrated & the offsets was ok, but the problem with the GPS is still there, it is just going haywire & i have a new Prearm: Bad GPS Pos.

Please note that the Copter is standing still at one place but in Mission planner it seems to keep moving around like crazy.

Same problem. Can not arm my Copter any more since I made the update to 3.1.5. I use the APM 2.5 with UBLOX GPS.
Every time I like to arm the system I get the massage "Prearm: Bad GPS Pos."
gpsstatus is 3
gpshdop: 3.44
satcount: 6 or 7 (I have set ahrs_gps_minsats to 4)

The HUD shows GPS: 3D Fix in white, so that seems to be ok.

I have no more ideas, hope anyone else have.

[quote=“Urknuff”]Same problem. Can not arm my Copter any more since I made the update to 3.1.5. I use the APM 2.5 with UBLOX GPS.
Every time I like to arm the system I get the massage "Prearm: Bad GPS Pos."
gpsstatus is 3
gpshdop: 3.44
satcount: 6 or 7 (I have set ahrs_gps_minsats to 4)

The HUD shows GPS: 3D Fix in white, so that seems to be ok.

I have no more ideas, hope anyone else have.[/quote]
I had a similar issue. I also had the “Prearm: Bad GPS Pos.” but when i entered the compass calibration page, nothing would happen when rotating the compass. You wouldn’t see the points being plotted. I also tried the accelerometer calibration, which when asked to put the apm level and press any key. nothing would happen, It wouldn’t go to the next step. I finally ended up uninstalling and reinstalling MP and that seemed to fix the issues. “Prearm: Bad GPS Pos.” went away…

[quote=“devveldogg”][quote=“Urknuff”]Same problem. Can not arm my Copter any more since I made the update to 3.1.5. I use the APM 2.5 with UBLOX GPS.
Every time I like to arm the system I get the massage "Prearm: Bad GPS Pos."
gpsstatus is 3
gpshdop: 3.44
satcount: 6 or 7 (I have set ahrs_gps_minsats to 4)

The HUD shows GPS: 3D Fix in white, so that seems to be ok.

I have no more ideas, hope anyone else have.[/quote]
I had a similar issue. I also had the “Prearm: Bad GPS Pos.” but when i entered the compass calibration page, nothing would happen when rotating the compass. You wouldn’t see the points being plotted. I also tried the accelerometer calibration, which when asked to put the apm level and press any key. nothing would happen, It wouldn’t go to the next step. I finally ended up uninstalling and reinstalling MP and that seemed to fix the issues. “Prearm: Bad GPS Pos.” went away…[/quote]

Did the APM arm even though the “BAD GPS…” notification ?
I have the same issue… GPS position travels few meters … and i can not arm in any GPS assisted mode

Found the answer… HDOP should be below the trigger parameter to arm (default is 2). :slight_smile: