I noticed while reviewing my flight log after today's test flight that the RC was not on the right spot.. I was just behind the Home point as per in picture and video below, but the Remote GPS kept jumping back and forth to across the street. I really could not tell with certainty wether it was doing it during the flight, but I did not have a single issue with GPS nor signal... any clues? has this happen to you? any fixes or considerations?

I was on airplane mode. Dual controller setup... today was the first flight with both.

Also, I noticed that I have a missing flight log. It was there, but now it is gone... I synced up on both controllers, but it is just simply gone...

I am concerned about the log dissapering and the TX signal not being accurate and "jumping" to the wrong location.
I know people have had issues with GPS on Bird... but I have not read on Transmitter....

at minute 1:16 on the video you can see the height dropping to -3.3 ft...       hmmm really?

Any feedback is appreciated.



I recorded using SHOU and it does not show the map... do not know why.. but you can still see the TX GPS position jumping....

I have heard of this a few times around the forum but no solutions that I have seen but then again , that was a week or so ago. I am sure you have searched around here as well.

Good luck.

Houston

houston Posted at 2015-3-29 12:52
I have heard of this a few times around the forum but no solutions that I have seen but then again , ...

I have not found any forum thread on the subject... Is there a way you can nodge me in the right direction? Thank you.

I think I have a reason of why the flight log is misssing. I might try something today to confirm. The idea is that supposedly the flight data log gets recorded on SD card as per manual. What happens if you eliminate data from card by formatting and then re-inserting on bird all of this without having syncked up to the App... My idea is that it would probably would be gone...

I will test different ideas... All surrounding the SD card and how it conveys information to the cloud.

I am sorry, I am not able to find this either but I know I saw it becuase yours was at last the second post I have seen about it. Perhaps someone else can help out.

My controller gps does not start to become accurate until after about 15 minutes being on and under open sky.

If its issues with height it will probably be the barameter sensor on the aircraft.

I had a similar situation where teh return to home height was 20m, sent the aircraft out some 50+metres descend to a lower elevation probably about 10m lower and when putting aircraft into Failsafe/ Return Home it returned at a lower height or around 10m from the original Home Point.

So looks like your aircraft is doing weird stuff also with regard to height settings which originate from the aircraft.

Just out of curiosity what is the build date of your aircraft ?

I contacted dji about this and also posted a thread in the forum about it. Dji reply ed saying that the problem is to much interference in my flying location and to make sure to always fly my inspire using the dynamic  home point feature NOT the remote/home point  

Not sure what the difference would be between setting the Home Point Manually or relying on the Dynamic mode.  Both surely relie on the GPS to fix their position and teh Barometer sensor to fix vertical height.  If both are not working, something has to give.

GB44 Posted at 2015-3-30 01:03
Not sure what the difference would be between setting the Home Point Manually or relying on the Dyna ...

DJI claims an accuracy of .5meters (1.6ft) on Vertical hovering accuracy... so maybe they stretched that out the truth a bit more... their Horizontal accuracy is claimed at 1.5m (5ft) for the bird, however it seems much more accurate on a Horizontal plane than Vertical on my bird.I will check built date and let you know once I get home!

I should be able to use the Dynamic home point and the recorded one before take off..otherwise DJI should not have included the feature, however the issue is not even me trying to set on dynamic home point but the fact that the point resolved for RC is on the wrong horizontal plane for more than 150 feet... way over the claimed accuracy for the bird... except the controller's GPS module's accuracy is not specified on documentation I can find.

I have not experienced the issue again...on different location... However I did noticed the RC dot going from blue to red color at a new location... I have not read about this to see what it represents.

genettico@hotma Posted at 2015-3-31 02:27
DJI claims an accuracy of .5meters (1.6ft) on Vertical hovering accuracy... so maybe they stretched ...

Correction... So during flight yesterday I was watching the BLUE DOT representing the RC controller like a hawk. It stayed with me the entire time.  On one of the flights it kept going from red to Blue, but I cannot find what this means anywhere... DJI needs to provide much more concise documentation with it's products. I do not have time to look thru 3000 threads/posts to find the answer to something that SHOULD BE on the manual and that even when looking thru google searches on forums I cannot come up with an answer. I have watched all the videos as well and cannot find anything. .. I just checked the flight log and it looks like my RC was about 1200ft from where I was... that is a HUGE MARGIN!! What is going on?? is the Log wrong? or the information provided during my flight? Again... I was paying attention to the dot yesterday and It never left my actual coordinate... but on the log it shows as if it was 1200ft away from me during the entire flight...

So:

What is the red color changing from Blue?
Why is the Log showing different than my "live" view while flying?

Im confused here... a little help?

genettico@hotma Posted at 2015-3-31 03:54

Notice the Home Point and notice the BLUE RC point that represents Transmitter to the extreme right of picture... thats about 1200ft away from where I was... (just behind the Home Point). If it reads the GPS signal of TX that far from where I physically was what would have happened if I went the opposite way thinking I have 1200 ft more when in reality It doesnt? It is a scary thought! I do compass Calibrations on EVERY site I fly, and if you notice I was not near power nor Interferance... even if I was this is to comply with FCC standards I believe and should not allow such interferance that would allow a 1200ft discrepancy!

genettico@hotma Posted at 2015-3-31 03:57
Notice the Home Point and notice the BLUE RC point that represents Transmitter to the extreme right ...

It is Actually 1483FEET or 452meters!

Man... customer support thru chat IS rough!... seems like language barrier has lots to do with it... As explained by DJI on chat.. the blue to red dot is weak RC GPS Signal on Transmitter. Not sure how that is the case when I get a perfect signal showing on the bird and the RC had completely un-interrupted signal.. but ok... at least I now know what the red dot means.... However yesterday the dot was blue the entire time... and even on the flight data shows it this way... just WAAYYY Off!!!

genettico@hotma Posted at 2015-3-29 22:35
I have not found any forum thread on the subject... Is there a way you can nodge me in the right d ...

Hello genettico, I opened a thread about this problem, I think you will find it at The third page of the forum now...there are so many new threads now. It's called "dynamic home point is moving and not correct".
It seems that the GPS in the controller or your tablet has not the same accuracy like the one in the inspire.
You can use it but keep always an eye on the map on the screen. Maybe they gonna fix this problem with a later update. Meanwhile I don't use this function anymore.

Hope this helps

patou72 Posted at 2015-3-31 05:13
Hello genettico, I opened a thread about this problem, I think you will find it at The third page  ...

Great info Patou. Thank you for the post... it definitely helps... Autum-DJI mentions that the jumping is caused by the poor accuracy of the GPS on the Mobile device when the RC GPS signal is too low... as it uses it to compliment the RC GPS. If this is true so then perhaps we should fly with WIFI off but not on Airplane mode which is what I tried yesterday .I have tried flying with airplane mode on some flights and with WIFI on on some other with the same result. There is something else to add to this problem. The fact that the APP was showing me the correct point while I was flying but that the BLUE point that represents RC  (though blue which means strong singnal as opposed to red) displayed 1485ft away from where I was POST flight... so the concern is... what do we believe?? the real time app? or the flight log?

Ok so I went out a bit ago to test exactly how is the RC feeding some of it's signal to the App while in flight and then the flight log.... For the sake of science... I tested flying on different modes, like wifi on and off, airplane on and off, and Cellular reception ON and off... Seems that the worse signal to RC location displayed on app is when flying on airplane mode, as the reception signal gets compromised and the accuracy diminishes. The funny thing is that the flight log data does not display the jumps of the blue dot or the changes of reception.... It simply displays the dot a different location, and it is stationary, without it showing the changes in reception as it shows on the video... I noticed you cannot set dynamic home point until after you start motors... Not for the aircraft and not for the rc. After starting the motors you can set it no problem to whatever is displayed on the app at that moment while on "live view", so if you have the wrong point on the rc you have to be careful as it will go to that point, if you make it land to the newly set home point. This is recorded accurately on flight log, but not the rc position as it was during flight.  The flight log shows a more accurate position as to where I really was... Interesting enough on the flight log you can see that it set the dynamic point to where the app showed it live, yet the blue dot for the rc is displayed at a closer range to where I was physically. I think I have lots of great useful interesting data, and hope DJI reviews the video attached and get something out of it that might help all of us. Please watch the video and enhance with feedback from personal experience or constructive comments, theories, suggestions.

http://youtu.be/Ia_sjREFyfo

genettico@hotma Posted at 2015-3-31 09:07
Ok so I went out a bit ago to test exactly how is the RC feeding some of it's signal to the App whil ...

http://youtu.be/Ia_sjREFyfo

PLEASE WATCH THIS VIDEO UPDATE

http://youtu.be/Ia_sjREFyfo

Ed-Tahoe, can you please review this video and forward it to colleagues for review? I think my flight log data is also very useful when compared to the video file!

You can expect an accuracy of around 20 feet or more, There is a correction method that creates a ver precise location. Unfortunately it is quite expensive, It entails the input of a correction receiver that triangulates the signals. The drift is due to defense of the USA so an enemy cannot use our technology to attack us. The Government can and does change the exact home point on a regular basis for security reasons. So, if you are 10 plus or minus feet that is actually very accurate.

rodger Posted at 2015-3-31 09:27
You can expect an accuracy of around 20 feet or more, There is a correction method that creates a ve ...

Thank you... But my concern is not over 20ft... I'm ok with that.. Even 50 ft is still ok in my book.. my concern is with the record on the flight log to show a discrepancy of over 1485ft.... As in yesterday's flight... And the difference from what shows live to what It actually records as what happened.

Thank you for taking the time to investigate this and document it as well as you have. It should be very helpful to DJI. I certainly will not be using Airplane mode any longer as a method of shutting off the various transmitters. I had experienced the same kind of discrepancy that you had and thought I had read that it might be due to the impaired TX visibility to satellites due to the iPad Air 2 covering it. From your video, I don't think this is true.

I will continue to watch this thread to see what develops. Thanks again for taking the time to investigate this and record it. Very helpful.

GB44 Posted at 2015-3-30 00:50
If its issues with height it will probably be the barameter sensor on the aircraft.

I had a similar ...

You have to set the return to home height.

rodger Posted at 2015-3-31 09:27
You can expect an accuracy of around 20 feet or more, There is a correction method that creates a ve ...

Rodger,

Didnt think that military restriction on GPS accuracy no longer applied, as even GPS in cars now are quite accurate.  I am aware of it, as I came across this restriction issue back in the 1990s when GPS technology was in its infancy for locating buildings and structures.

Hello James ,

Thank you for contacting DJI Technical Support.

Acctually this problem is affected by the environment.
So for garantee the safety ,it is recomment to us the record homepoint .
If you are using the RC homepoint ,please make sure you have recorded it successfully ,and you can find the blue marks in the APP .

In case ,If you trigger the RTH ,and found it flight to the bad way ,please exit the RTH and take back the control .

Hope that will be help .

ps . I have also communicated with our R&D team ,and they will work to make it more stable .

Thanks for your understanding .

Best Regards,

DJI Product Application Technical Support

ruddy951 Posted at 2015-3-31 20:36
Hello James ,

Thank you for contacting DJI Technical Support.

I think their (DJI) description of "...affected by environment..." is a little to general and lacks descriptive precision.

Im not attacking anyone here... not DJI nor any individual.. however I feel that DJI (though understandably so) tends to go for the most general answer to customers (as if prompted by a script) without sometimes looking into details of customers willing to share (me one of them) specific flight data from dozens, hundreds or perhaps even thousands of pilots with legitimate issues. I think it is understandable they handle answers the way they do, as to protect the company with possible deny ability... like this they can say the bird crashed because we were flying on a non-suitable environment (perhaps one of the reasons they give this general answers).  

I have flown on places where the nearest electricity cables/towers and radio interference (that's obvious) caused by towers and other "sense-full " environmental "issues" are 15 radial miles  away from RC/BIRD and  where the terrain is flat, visibility is as far as the eye can see, with no obstructions and I still have gotten same results.

The Test I just did yesterday is NOT perfect by ANY means..but it does offer some valuable data that seems to support that usage of WIFI OFF but not on AIRPLANE mode nor Cellular is the best way to give the RC GPS signal a better chance at pin pointing a more precise location with a more reliable signa, regardless of the "environment" being perfect or not (as mine for the test was far from it).


What environment affects the GPS on the bird and RC? we know what they (DJI)  has mentioned before and that makes perfect sense. (i.e buildings, obstructions whether natural or man made, electromagnetism, radio interference, Microwaves, Cellphone signals from towers and perhaps your cellphone, WiFi signals... to name a few)

So... if we try and look for a place to fly that would diminish (key word being "diminish"... as I do not know  a single place on planet earth where such "null" interference  environment exists)  the environmental effects they argue are affecting the bird and/or RC will be gone?

Oh no.. because then I have to worry about my Ipad Air 2 covering the GPS module on RC.... as Bkacman has read before and voiced on post above..

So maybe... if I fly in the middle of the Saharan dessert on a perfectly sunny day and I manage to separate myself from the Ipad via a 10ft Lighting cable as to not cover the GPS module on the RC I have a good chance of getting the signal to work to not show a discrepancy of not more than say 50ft?
Flying in such place would eliminate most practical uses of the bird... but if this is the case I feel DJI has to provide a "rule of thumb" "best environment flight areas" and specify minimum flying distances to interference sources... otherwise we can all just expect we can only fly on desserts or places like it... hmm not so practical, nor useful..

The Remote controllers have a built in GPS module, like that of a phone... and if you turn off your cellphone cellular service to OFF and still have the WIFI OFF but not on airplane mode,  the built in GPS module is not nearly as "environment affected" as our RC's. You can still use it to navigate on certain apps (very  accurately) thru cities, buildings, interference galore heavens with minimal disruptions...  
So think about this: we are "complimenting" the RC reception via the Mobile devices built in GPS as what it appears to be proven on the video I made... and as I was told by DJI rep over chat yesterday...

So we have 2 modes of increasing accuracy and signal... one from RC module, and one from mobile device... however the indication on flight log is OFF from what I see on the live feed by a HUGE margin (1485ft).. even though I never had lack of signal at any point...  I believe this is a definite software bug and not a hardware issue, however I might be completely off base... and wrong and I am willing to admit that, if someone offers a compelling supported argument other than "affected by environment".

I want to help fix issues if they are that... but I will not continue to dedicate time (MY TIME) if DJI is not willing to look at findings and assess whether or not it is viable information before I get the default "fly somewhere else" answer.

rodger Posted at 2015-3-31 09:27
You can expect an accuracy of around 20 feet or more, There is a correction method that creates a ve ...

Wrong - SA was turned off in May 2000 there is no longer selective availability within the GPS timing signal.

i have the excact same  issue.  it seems to be only in one location i fly.   yesterday my blue controller icon stayed at my house, while me and the copter flew a mile away.   haha well at least it really would return to my home if I set it to controller.

for now i just use home point as its very stable.   try another location, and see if it goes away...
are there any power stations or lines near you?  there are some med. sized ones  within 500ft. of me.

EDIT,  i have found the same issue at a low interference area, the beach.

johnmont250@hot Posted at 2015-4-1 00:13
i have the excact same  issue.  it seems to be only in one location i fly.   yesterday my blue contr ...

As posted above... I have tried different areas..... all the same result!

bummer,  not sounding good.  I have another set up, i will try it if the wind dies down, but sounds like something is wrong with our controllers gps, and might need to be sent back... the controller has its own gps and the copter has another gps puck

What markjacobs is referring to as "SA" is Selective Availability which is what the dept of defense considered their protection mechanism, and he is correct that it is no more.

There are other systems in place to increase the accuracy of GPS down to inches. These systems started as "DGPS" or Differential GPS. There were stations that monitored, processed the slight differences of position at fixed sites versus their reported position, then rebroadcast that error message to "differential receivers".

Now we have essentially this same thing that people like surveyors use which takes a known point, collects the reported position via GPS, and reports to other local GPS receivers so they can remove that error.

The Wide Area Augmentation System (WAAS) is now the navigation standard for aircraft. WAAS is essentially the latest generation of DGPS. WAAS equipped GPS receivers allow aircraft to fly very precise procedures similar to those previously only flown by ground-based navigation aids. A quick google search for ILS (instrument landing system) vs. LPV (localizer performance verbal guidance) is interesting. You'll see there is a little of all these generations of technology that makeup an LPV approach. Kinda interesting to any aviation nerd.

GPS signals are VERY weak. Because of this it can take only a small amount of interference to really mess up some receivers. There is a pretty wide spectrum of antennae and receiver quality out there with the expected differences in how accurate, sensitive, and error resistant they are. Old DGPS era GPS units only tracked 4 - 6 satellites at a time. Newer receivers are more typically 12 channel recievers so there is more signal in that makes the position more accurate and able to update more quickly.

genettico@hotma Posted at 2015-3-31 09:53
Thank you... But my concern is not over 20ft... I'm ok with that.. Even 50 ft is still ok in my bo ...

That is a very legitimate issue and concern.

GB44 Posted at 2015-3-31 20:30
Rodger,

Didnt think that military restriction on GPS accuracy no longer applied, as even GPS in c ...

They have been relaxed quite a bit. I think down to 7? The correction radio signals which triangulate still exist. For example, check a Surveyors Transit that is using GPS. They use the GPS and triangulation. When a Surveyor is marking out property it has to be spot on, no room for error at all. The Military can put a Tomahawk through a window from 1500 miles away. Pretty amazing. Having said that, The Military can change the accuracy of the GPS System in a Heartbeat. We don't want an enemy using our precise navigation system to attack us!

Very interesting along with troubling! Let me ask you this? If your Tablet has Cellular, did you have it in Airplane Mode" It looks like some kind of interference (noise) may be moving things around and causing havoc with the program instrumentation. A Cell Tower close by where you were flying?

for me, one spot i fly had no cell service, the other was dirty, and i still got jumping icon at both sites

Bkackman Posted at 2015-3-31 10:50
Thank you for taking the time to investigate this and document it as well as you have. It should be  ...

Thank you for your support! BTW.... I tried my ipad Air 2 with an extended 6ft lighting cable.... and still same result!

rodger Posted at 2015-4-1 04:15
Very interesting along with troubling! Let me ask you this? If your Tablet has Cellular, did you hav ...

Watch the video above the one with large BOLD LETTERS... "PLEASE WATCH THIS VIDEO UPDATE" I think it will answer your question.

As far as for the flight on pictures above I flew both on airplane mode on one flight and WIFI OFF but not on Airplane mode on another.I do not have Cellular on my IPAD AIR 2.  I use my Ipad Air that has cellular connection as hotspot for the IPAD AIR 2 (which is for MAIN controller) to download maps and after/then, I turn IPAD AIR (for SLAVE controller) to Airplane mode...

At the end I fly:

Main Controller: Ipad Air 2 (airplane mode/not airplane mode but WIFI off) (no cellular connection)
Slave Controller: Ipad Air (Airplane mode only after using it as HOTSPOT for MAIN to download maps)

Why would I just not use the IPAD AIR as the MAIN? because of the stupid GLARE!!... even with Shade... on sunny days it is difficult to see.... The built in Antiglare of the Air 2 Works better....
Oh... btw the FLYSIGHT BLACK PEARL MONITOR ROCKS!!!

Im about to post a video comparing Ipad Air 2 to it!

Genettico, the effects by the environment is not just a cop out.  Have you noticed the solar activity over the last few weeks.  We had abnormal activity.  The K index went to 8.  That is severe interference on GPS.  Now beyond that, I have looked at both of your videos and my estimation is that you may have a bad GPS unit.  Note that the GPS in the Tx is not as sophisticated as the one in the Inspire.  Do you have a two Tx unit or are you on only one Tx.  If you have two, can you switch the slave to master and see if you are having the same issues.

genettico@hotma Posted at 2015-4-1 05:56
Watch the video above the one with large BOLD LETTERS... "PLEASE WATCH THIS VIDEO UPDATE" I think  ...

Try the Hoodie? Ed is right, There have been a lot of Solar Flares which reek havoc on electronics especially in the RF spectrum.

Tahoe_Ed Posted at 2015-4-1 07:19
Genettico, the effects by the environment is not just a cop out.  Have you noticed the solar activit ...

I did not imply anywhere the environmental effects are a "cop out"... On the contrary, I'm well aware on how they affect signal... I actually keep close track on the K Planetary index, I even have a direct link on my iPad and check it everyday before I fly somewhere, and when I was flying during the videos it was a mere 3 and well below the level of  a geomagnetic Storm and their adverse effects on GPS signals. I do have two controllers, and will do as you suggested... I feel like there is missed informational this post  to be considered....or that was overlooked all together...it seems you believe I am negating environmental factors and how these interfere with our equipment..
Anyways....
Thanks for the reply.  I will update with results!

Tahoe_Ed Posted at 2015-4-1 07:19
Genettico, the effects by the environment is not just a cop out.  Have you noticed the solar activit ...

I did not imply anywhere the environmental effects are a "cop out"... On the contrary, I'm well aware on how they affect signal... I actually keep close track on the K Planetary index, I even have a direct link on my iPad and check it everyday before I fly somewhere, and when I was flying during the videos it was a mere 3 and well below the level of  a geomagnetic Storm usually associated with adverse effects on GPS signals. I do have two controllers, and will do as you suggested... I feel like there is missed informational value on this post  to be considered....or that was overlooked all together...it seems you believe I am negating environmental factors or saying that DJI is just blaming these as the only cause... When that's not the case.. I am merely asking for data to be considered before issues are tagged as "environmental" with such ease...and for DJI to provide what these enviromental factors are in more detail, or at least things to consider other than the most obvious ones stated on manual so we do not risk crashing because considerations like geomagnetic storms are not disclosed. Ultimately WE the pilots are responsible for ensuring we inform ourselves with anything and everything related to our birds and fly with the limitations of the equipment we use, but we need to understand these, and for that, we need specific information which I think DJI can provide a little more in detail to the consumers as they are the ones that built the craft.
There has to be more documentation, and more descriptive in nature..... It is hard to find sometimes even simple things that should be on the manual...
Anyways....
Thanks for the reply.  I will update with results!