Repeated mid-air APM reboot - only happens at one flying site - possible weather radar interference

I have three flying sites that I use depending on weather and availability. My primary flying site is located only 800 meters from a weather radar and I have been having repeated in-air reboots when flying from that flying site only. Fortunately, being new to the ardupilot system, I put it in a slow flying high wing airframe and have enough years of RC experience to catch it and go manual each time.

Given that so far I have only experienced the reboots at the one location and the weather radar is the only powerful emitter I am aware of operating in the area, the weather radar is now the leading suspect. I was wondering if any other users have had experience making their hardware a bit more resistant to EMI (Electromagnetic Interference). As the hardware comes out of the box it contains little to no protection.

Knowing what mechanisms could cause the processor to re-boot would help me implement a more targeted solution than adding chokes to leads and wrapping leads and the processor in alumnimum foil.

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Have you analyzed the logs for the flights in question?

If it is truly rebooting, as in a power-on reset, I would think a new log would be created while in flight. Your observations do lend credibility to the site as the problem, it only needs to be determined which part of your electronics is suffering from the interference.

That kind of energy could be simply overloading the rejection capability of the receiver and not the APM. It could also be soaked up by the servo leads and causing spurious/erratic function.

More data will be needed to be sure.

Because S-Band operates in the range of many 2.4 GHz Tx/Rx systems, your site is definitely suspect - if your RC gear is 2.4 GHz. From the Wikipedia article:

The S band is part of the microwave band of the electromagnetic spectrum. It is defined by an IEEE standard for radio waves with frequencies that range from 2 to 4 GHz, crossing the conventional boundary between UHF and SHF at 3.0 GHz



Are you running APM off one supply, or are you powering each rail separate? It would be good to try powering each rail separately at that site to see if it happens, this is assuming you are powering off one source now !

You probably will have to shield any long wire runs (more than a few inches) and use some .001 bypass capacitors on the DC lines.

Or, as you suggest, just don't fly in that area.

Have you checked the 'vcc' value in the logs?

I did fly couple of time my copter with APM2.0 in Auto mode close to a weather radar and I did not notice any interference, but is good to know from other people experience.

I am leaning toward Stephen's 2nd suggestion unless the suspect site is a premium place to be.

If the site is a must-do, you will have to start the process of hardening your aircraft to EMI. It will be a time consuming process but not necessarily an expensive process. As Stephen suggested, sheilding the long wires is a start. How to do this?

Try self-adhesive copper foil tape. This would allow you to also solder capacitors to the shield for additional decoupling. 3M has a line products made just for this. Click HERE.It is easily cut with scissors and can be shaped to many surfaces.

The goal is to attentuate the unwanted energy and also maintain your control of the aircraft through the original RC system... which you still have not mentioned what gear/frequency you are using.


Hi Paul, do you have a confirmation about weather radar afecting APM2.5? This really interest me.

I did a fly last week with APM2.5 powered by 3DR module, and I did have the same in-air reboot as you, see my link below. At that time I did not make any connection to weather radar site, since I did fly before on this site, but with APM2.0 and all was OK. Maybe radar was powered off...

Do you have some tlog or log from that time where did you have the in-air reboor because of weather radar? You said in another post you did see a counter reseting in log which give you the confidence it was an in-air reboot. Which param is this?

I want to compare your logs with mine.

Disarm at 80 m, close to a weather radar

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