Losing GPS signal recalibrate compass?

Brent D · Sep 5, 2016

Was flying last evening and my H would randomly pop up that big message warning - maintain manual flight... recalibrate compass.... I think thats what it was.....

I noticed the H would keep doing it over and over. I was flying really close to myself (20 meters) or so.
I moved it out a bit further and it stopped.

This is after the latest FW update and I did calibrate the compass before hand.
Any thoughts?

CHEERS

Rayray · Sep 5, 2016

In Angle mode?

Brent D · Sep 5, 2016

Rayray said:
In Angle mode?

yes I only use Angle

CAPTAINDRONE · Sep 5, 2016

There were many "unlisted" refinements in the latest firmware update. The compass alert was one of them. Many have had it appear while the craft is either on the ground near them or in the air near them. I'm sure Yuneec will tweak this in a future firmware update.

In the DJI world of drones, this notification will also pop up along the top portion of the screen now and then for no apparent reason when it never did before. The quick fix on the Phantom/Inspire is to flick the drone in and out of GPS mode.

Brent D · Sep 5, 2016

Going to test again today - even though it is quite breezy! Thanks guys for the quick reply.

Rayray · Sep 5, 2016

A weird deal, Brent. You apparently did all new calibrations, including the gyros. Might try re-binding. It is apparently flying OK other than the warnings, right? Other than a voodoo charm, Yuneec. Tim Terrones is a good guy.

[email protected]

Brent D · Sep 5, 2016

Rayray said:
A weird deal, Brent. You apparently did all new calibrations, including the gyros. Might try re-binding. It is apparently flying OK other than the warnings, right? Other than a voodoo charm, Yuneec. Tim Terrones is a good guy.

[email protected]

Thanks. Yep. I did all of the usual stuff. I will recalibrate and rebind everything today.

If no luck I will contact him. CHEERS

Brent D · Sep 5, 2016

Just back from a flight. Re calibrated the compass and accelerometer and everything seems fine.
No weirdness whatsoever. I didn't go far though because it was way too windy. Next good day I will try again.

vr-pilot · Sep 5, 2016

Solar storm activity and earth magnetic field stability were both reported as problematic in the last days... could definitely be the reason for strange control behaviour. Being surprised by an unexpected "GPS off" wind drift can be "fatal"...

Brent D · Sep 5, 2016

Sounds more and more like that could be a possibility.

Rayray · Sep 5, 2016

vr-pilot said:
Solar storm activity and earth magnetic field stability were both reported as problematic in the last days... could definitely be the reason for strange control behaviour. Being surprised by an unexpected "GPS off" wind drift can be "fatal"...

I fool around with Ham Radio, which is subject to various solar conditions, and get NASA alerts of geomag storms, etc. There is info on this forum about the K index. As a practical matter, an index of 5 or more is indicative of possible satellite interference, including the orbiting GPS birds. If you start your H in a usual place, and you normally have 12 or 14 birds (on the H) and today you only have 10 or 11, the reason could well be solar storms blocking the weaker, more distant sats. Rarely a big deal.

vr-pilot · Sep 5, 2016

Brent D said:
Sounds more and more like that could be a possibility.

As far as I understand, solar storms and their aftermath compress the actually "round" earth magnetic field on the sun facing side and expand it on the shadow side.
This causes weakend/deflected GPS signals and additionally the earth magnetic field strength is lowered significantly over a period of days, recovering only slowly.
As our drones' sense of lateral orientation depends 100% on these parameters, it is no wonder that bad things could happen. At least the baro sensor works reliably as always...

Rayray · Sep 5, 2016

vr-pilot said:
At least the baro sensor works reliably as always...

LOL, yep, as always...take off at -3' ,land back in the same spot at +14'. I wonder if it warns of a storm coming?

vr-pilot · Sep 5, 2016

10 ft = 0.01 inHG (1hPa = 30ft), so 17 ft altitude difference is really only a small change in metrological numbers. Indeed this would indicate a meanwhile lower air pressure. But better assuming a landing at +14 ft than at -14 ft....

WilsonFlyer · Sep 5, 2016

vr-pilot said:
Solar storm activity and earth magnetic field stability were both reported as problematic in the last days... could definitely be the reason for strange control behaviour. Being surprised by an unexpected "GPS off" wind drift can be "fatal"...

I saw that on the aeros too. I wonder if that's why so many seem to be having issues. Admittedly, I haven't flown much in the last several days.

Rayray · Sep 5, 2016

vr-pilot said:
10 ft = 0.01 inHG (1hPa = 30ft), so 17 ft altitude difference is really only a small change in metrological numbers. Indeed this would indicate a meanwhile lower air pressure. But better assuming a landing at +14 ft than at -14 ft....

I don't think the H uses it to land. There's a good reason to want the IPS, which works good.

vr-pilot · Sep 5, 2016

WilsonFlyer said:
I saw that on the aeros too. I wonder if that's why so many seem to be having issues. Admittedly, I haven't flown much in the last several days.

I flew the YTH with FW v2.21 only in the evening hours (just before or during sunset) the last days. I just noticed that it took a little longer for GPS lock but strange compass behaviour was not noticable. Everything under control. But I rejected actually planned "GPS off" test flights (e.g. what happens/displays when switching on "Return home"?), because I read about the solar storms and magnetic field abnormalities. And as it was quite windy I did not want to risk too much...
I think the sun facing side (bright daylight time) is the more problematic on that issue. Also it seems to be more relevant the closer you get to 60°N/S LON. I am "only" at 54°N010°E (Hamburg, Germany).

Typhoon Charlie · Sep 5, 2016

I use this app, it will send you notifications when solar activity changes.

Apple: Hover - #1 Drone and UAV pilot app! on the App Store

Android: Hover - Drone & UAV pilot app - Android Apps on Google Play

vr-pilot · Sep 5, 2016

Typhoon Charlie said:
I use this app, it will send you notifications when solar activity changes.

Apple: Hover - #1 Drone and UAV pilot app! on the App Store

Android: Hover - Drone & UAV pilot app - Android Apps on Google Play

Thanks, I use windyty:
Windyty, wind forecast
It is also available as an app. Under detailed forcast/airgram is a forcast chart for fluxes&radiation. That and all the wind etc. information and depiction is really useful...

vr-pilot · Sep 5, 2016

Rayray said:
I don't think the H uses it to land. There's a good reason to want the IPS, which works good.

I think it is for the YTHs the same as for the DJIs: baro reset on power on and after landing. Altitude then shows about 0m/ft. A GPS altitude would be too speculative/unprecise. The YTH without RS has no IPS so it depends on the baro sensor. Looking at "Home" mode (since FW 2.21) it is programmed to descend to about 6 m (20 ft) rapidly, than slower until it simply touches ground. IPS should not be used (OBS and herewith the RS module (including IPS) is recommend to be turned off during T/O and landing by Yuneec), as it would be problematic when e.g. landing in high grass.
I noticed a soft landing in high grass (up to the props) with OBS off. Until now I did not really try the RS/IPS during landing, low flying or indoors. That will be interesting. I got the carbon prop guard ring since last Tuesday. I still have to test a lot of things...