Hi all just got a phantom 2 vision plus v3 love it but wanted to check for some reason when the craft is on the ground it reading its 45-60 foot alttitude completly lost why is this something I missed??? Did the calibration as stated on quick start menu.
Also first sign of low battery would not let me gain control red lights flashing still 10%. Battery but landed on my garage and rolled of very sad but is still fine just little scratches guess more fool me for not doing in a field but don't understand why would not let me gain control.

Ps sorry for all the Qs bug does anyone know if you can take the phantom on the plane as don't trust baggage controllers as could damage it.

Many thanks in advance
Mark the learner

mark,  there do appear to be initial reading errors for the altitude, mine does it to.  it seems like after either a period of time or after a few successive boots, the craft will eventually hone in on the proper altitude.  i have noticed invalid readings like you mention however.  watching it during flight is definitely one of the things i am very cognizant of doing.

as for battery, i believe that at a certain level (which i think 10% would be) it will not let you fly and overrides to do nothing but RTH or land where it is depending upon distance and battery level.  recommendation is to always fly back  home and never go below 20-25% battery leaving that last part for your return and landing.

as for carryon, you can certainly carry it on, search this forum and you'll find many people that have taken their phantom through security and on the plane.  just have to be aware of all the things to focus on but you certainly can do it.  i, like you, would not check it as a bag either.

gnixon2015 Posted at 2015-2-3 01:08
mark,  there do appear to be initial reading errors for the altitude, mine does it to.  it seems lik ...

Thanks very much I shall keep trying see if brings it down certainly will bring down when gets to 25% battery have to learn the hard way least no major issues. Will search regarding taking on flight.
Thanks again

gnixon2015 Posted at 2015-2-3 01:08
mark,  there do appear to be initial reading errors for the altitude, mine does it to.  it seems lik ...

Mine does, too.  I figured it was measuring from sea level.  But I haven't bothered to compare the Phantom's readout to actual sea level charts.  I'm also not sure if it gets altitude from GPS or from its barometer.

Any idea on these?

markebdavies, there are two low battery stages -- low and critical low.

When the battery reaches the low level, the rear LEDs will begin to flash slowly and a message will appear in the DJI Vision app. Ideally, you should always land before the battery reaches this level.

If you make it to the critical low level, the rear LEDs will flash quickly and your Phantom will auto land at its current position. When the auto landing process starts, you might be able to give it full throttle up to slightly adjust the landing spot. But, you'll most likely find you have little control -- if any.

um, if it used altitude relative to SEA LEVEL it would be a useless feature.  i mean how many people live more than 400ft above sea level, like billions?  if the altitude reading was relative to sea level ill bet half of us couldnt even take off due to the 400ft height restriction.    and gps doesnt have altitude only position, the barometer calcs altitude

Friffy1 Posted at 2015-2-3 01:19
Mine does, too.  I figured it was measuring from sea level.  But I haven't bothered to compare the ...

That is what I thought possible measurement from sea level but trail and error makes me worry when set to land though...

PhantomHelp Posted at 2015-2-3 01:20
markebdavies, there are two low battery stages -- low and critical low.

When the battery reaches t ...

I guess not to risk low battery in the air or do it when plenty of space was just to keen to have ago before it got dark. Thanks

Oh boy, Friffy! Your post in contradictory, you're so confused about GPS/barometer/sea level. Why would it (what?) calculate from sea level

A barometer calculates  air pressure to determin altitude, GPS calculates the distance between the receiver and the satalites at a specific time. With very few exceptions, sea level is more or less "0". But I can imagine you'd need a chart for this lol.

So gnixon2015  is correct, it uses the barometer to determine altitude. Glad I could help resolve your confusion.

gnixon2015 Posted at 2015-2-3 01:37
um, if it used altitude relative to SEA LEVEL it would be a useless feature.  i mean how many people ...

Well, it's got to be relative to something.  I've been curious about it...  So if it's relative to the ground at takeoff, what's the altitude if you take off from a bridge and fly it down?  Does it start at 0 and go negative?

Friffy1 Posted at 2015-2-3 05:54
Well, it's got to be relative to something.  I've been curious about it...  So if it's relative to ...

Yes it does, it will go negative if you start from a higher place and say fly down into a valley.

markus2015 Posted at 2015-2-3 02:43
Oh boy, Friffy! Your post in contradictory, you're so confused about GPS/barometer/sea level. Why wo ...

Markus,

I guess you're not aware...  That's how altitude is measured by aircraft.  Flight level uses sea-level pressure to calculate altitude.  I'm not saying it is directly comparable to sea-level or ground-level for that matter, but is based on sea-level pressure.  There's very little confusion on my part.  I know how altitude is determined in planes and presume something similar in small drones.

Gerry1124 Posted at 2015-2-3 05:59
Yes it does, it will go negative if you start from a higher place and say fly down into a valley. ...

Very good to know!  I've only flown over relatively flat areas.  Thanks!

Friffy1 Posted at 2015-2-3 06:08
Markus,

I guess you're not aware...  That's how altitude is measured by aircraft.  Flight level u ...

Aircraft set their altitude to barometric pressure.  Above I think it is 18,000 feet, they change barometric pressure to 29.92.

Gerry1124 Posted at 2015-2-3 05:59
Yes it does, it will go negative if you start from a higher place and say fly down into a valley. ...

I guess I will "pile on" here. I have posted about this before. In my view, at least in my case, there is an issue with the altimeter. MY P2V+ V2 has been terrific...many flights, no significant incidents, but after all of my rigorous pre-flight routine, altitude displayed on my iPhone often starts at -345 ft, (I am essentially at sea level) and varies from there. If I then power-cycle Phantom, sometimes it comes closer to reality, sometimes not, so as in the example of flying today, after power-cycling Phantom a third time, ok.

As I have stated before, altimeter DOES matter, both in terms of RTH and respecting the 400 ft. ceiling. Likely there is something wrong with my Phantom, but the very last thing I want to do is ship it off to someone for however knows how long, and what they might do. Bottom line - I spend about 25% of first battery just getting an altimeter reading that I can trust and won't cause a problem. Believe me, if Phantom thinks it is -350 ft. and you test RTH, it will climb to your RTH setting. Anyway, enough said, a bit frustrated, but otherwise happy with my Phantom. Just wish there was some fix for this.

perdidoflyer Posted at 2015-2-3 06:17
I guess I will "pile on" here. I have posted about this before. In my view, at least in my case, t ...

These barometers are not built to the same quality as an aircraft.  There might be some dust or something on the port for the barometer.  I do know they vary.  When I do any work inside, I can get varying numbers on mine sitting in the same  place on my desk powered on,  I pick it up and raise it to the ceiling and back to the same place and get a different number than the first time.  But they do the calibrations approximate to 0 feet from the takeoff point to determine RTH altitudes.

Dam you would think brand new out of the box it would be perfect or a way you could reset level for the cost of it. Thanks everybody for your support on this.

Gerry1124 Posted at 2015-2-3 06:26
These barometers are not built to the same quality as an aircraft.  There might be some dust or so ...

Gerry - thanks. Admitting an apparent lack of knowledge, where is the port for the altimeter? I recall a reference to a "tube" but from what I know as to what is on my landing gear, I have two antennae, and the cable to the compass.

Gerry1124 Posted at 2015-2-3 06:26
These barometers are not built to the same quality as an aircraft.  There might be some dust or so ...

Gerry - thanks. Admitting an apparent lack of knowledge, where is the port for the altimeter? I recall a reference to a "tube" but from what I know as to what is on my landing gear, I have two antennae, and the cable to the compass.

perdidoflyer Posted at 2015-2-3 07:26
Gerry - thanks. Admitting an apparent lack of knowledge, where is the port for the altimeter? I re ...

It has to be on the unit inside somewhere,  I only had the top off once to shield the compass, I did not tear it all apart.

gnixon2015 Posted at 2015-2-3 01:08
mark,  there do appear to be initial reading errors for the altitude, mine does it to.  it seems lik ...

Thanks for advice with more use it has come down bit by bit. Appreciate the help

Gerry1124 Posted at 2015-2-3 07:30
It has to be on the unit inside somewhere,  I only had the top off once to shield the compass, I d ...

The barometic altimeter is part of the IMU and resides inside the NAZA-M box, so you can't see it. airplanes use a Pitot tube facing the rear of the aircraft. Because quadrocopters, unlice airoplanes, fly in every direction it would be a bad idea having it ouside of the shell. If wind go to it, it would constantly get wrong readings and go crazy. Hovering would act like a drunk rabbit  - I have seen one by the way :-)

There is no (visible) hole in the NAZA, but that does not mean it's air tight. There surely is no vacuum in there, else the barometer would not work. So I figure, since wind also gets into the shell through the venting slots caused by the props and induce turbulence inside the shell, it would have to be tight enough to get no interference, but breathable enough to messure change of atmospheric pressure.

Would anybody Volunteer to drill a tiny hole in the IMU and report back if it changed anything?

But I don't get the fact that the altitude reading (from take off point to flight height) is pretty mutch accurate (+- 0.6 meters), so why is the altitude reading of the take off point mostly wrong? Is GPS perhaps also (to some extent) used to determin altitude?

I also don't understand why DJI doesn't implement a "tara" like scales have. So when you start your phantom, it will automatically have altiture "0" feet.

Have any of you got any thoughts to this?

markus, i considered a tare weight (unladen weight) approach to the altimeter like you described.  seems like one of the issues could be that IF the device is not entirely accurate, then if you tare it out to zero and then it starts reading pressures along the way, your error could go from starting out (and slowly subsiding) to starting at 0 and slowly creeping back in.  im not entirely explaining this well nor do i understand what besides turbulence would cause an inaccurate reading to begin with, but one would only assume that if a tare approach would have worked, they should have defn implemented that by now.  maybe some other aero engineers could share thoughts too...

I just figured that the air pressure is constantly changing (same location, different day) due to change of weather etc. That might have something to do with the barometer getting a false reading before take off and therefore you'd have different ground alltitude readings at different times.  - Just a thought -

I wish DJI would be technical specific about these little gadgets (altimeter, Gyroscope etc,) - it surely interests me.

markus2015 Posted at 2015-2-4 01:41
The barometic altimeter is part of the IMU and resides inside the NAZA-M box, so you can't see it. ...

actually you should have near 0 after each power up which may vary a bit as the electronics warm up but it shouldn't be any large differences.  In the past DJI recommended send in for repair on units that show big differences from 0 at start up.

swomilan.email Posted at 2015-2-4 02:19
actually you should have near 0 after each power up which may vary a bit as the electronics warm u ...

what?  DJI's response to someone's inquiry about odd behavior was to send it in for repair?? BIG SHOCKER.  at the rate i have seen their service model on this board, coupled with the service i received when ordering directly from them, coupled with the fact that it is a month or more of transit time back and forth, they couldnt pay me to send mine back in...

gnixon2015 Posted at 2015-2-4 02:39
what?  DJI's response to someone's inquiry about odd behavior was to send it in for repair?? BIG S ...

Send it in, don't send it in, replace the Naza-M controller yourself or let someone else do it for you or keep flying with the offset since it won't have an effect on the function of the unit unless the altitude offset keeps varying. In the end it's an individual choice to make