Hello all, just got my Spark - 2nd hand and took it out for a test fly this morning.
Everything seem fine, was light wind, very sunny, empty park.
Anyway was flying around and I noticed that the VPS icon was red with a (!) icon, didnt really worry me too much and to be honest I didnt take THAT much notice - it may have come good when I gained some height.

Anyway had about 40% battery left and thought id take it up to 120 meters for some photos - working great, until I tried to decend.

While holding down on the controller it seem to be very slow to decend, I checked the vertical speed and it looked like it was working - cool ...
Then I would see the VPS altitude pop up and showing 2 meters... then dissapearing ... didnt think too much of it until I notice the vertical speed going to zero every time the VPS data would show 2-15 meters randomly.
At this stage the low battery alarm started going and auto land was initiated - at about 60meters (I since have read that I could have held the throttle stick up and it would have "taken off" again).
I flipped it to sports mode (shoulda gone atti) and tried to decend / move the quad closer to me - slowly it came down...
At about 20meters from the ground it started to decend very fast, I pushed up on the throttle and it come down to a nice landing.

Straight away at the park I uninstalled DJI go and reinstalled - 2nd battery had the same issue.

- Took the Spark home and refreshed the firmware, tested it on the table (probably not the most thourough test) and it didnt seem to make any difference.
- Downgraded the firmware, updated DJI Go app.
- Recallibrated the IMU.
- Downloaded the logs and imported them to check the data - you can see in the VPS column that it would show N/A most the time then flash up 2m - 15m - this is when the quad would stop decending and hover whilst at altitude. IMU altitude was always correct but VPS showing irradic values.
- Replayed the flight log in the DJIgo app and the altitude showing always the correct value but I can see that the vertical speed it going to zero many times - showing that it was pausing during decent due to faulty VPS data.

Ive included a screenshots of the log I uploaded so you can see what im seeing.

If I disable all Visual Nav Settings will this problem go away ?
I really dont want to send it back ....

Using OTG cable, cant really think of anything else to try - yes there are no stickers on the downward sensors ;) I tripple checked lol...

Cheers !

Was it foggy..  That is exactly what people describe happeing when there is fog or they fly above a cloud... if no fog or cloud then maybe there is dirt on your downward facing sensors.

LouisP Posted at 2018-1-5 19:56
Was it foggy..  That is exactly what people describe happeing when there is fog or they fly above a cloud... if no fog or cloud then maybe there is dirt on your downward facing sensors.

Hi Louis, well I cleaned the 2 red windows and the camera window with a microfiber cloth before I test flew, they look perfectly fine and no it was a beautiful clear day, ill throw up one of the photos I took and another screengrab of the log still showing the VPS coming and going on my stressful decent

Everythings recharged, downgraded the firmware, going to go visit a buddy and see if it freaks out in his backyard.

Just want to add that I rolled back the firmware to V01.00.0800 and had two great flights.
VPS seem to be working fine, done 3 trips to 400ft and straight back down, keeping my eye on the vertical speed / VPS alt warnings and nothing showed at all.
Done alot of skimming off the ground at about 1meter, was rock solid.
Threw it in sports mode and done some fast forward and backward moving decents - was great.

I should upgrade it back to .0900 firmware to see if the problem returns and confirm it, ill try over the next few days and report back but will take it out trashing it a bit before I roll it back and just check that its working good - well thats my excuse anyway

Magpie wasnt worried at all about the Spark, he let me follow him around for a good 7 mins while he picked worms out of the grass - video quality at dusk was better than expected but far from perfect.

Chances Posted at 2018-1-6 01:50
Just want to add that I rolled back the firmware to V01.00.0800 and had two great flights.
VPS seem to be working fine, done 3 trips to 400ft and straight back down, keeping my eye on the vertical speed / VPS alt warnings and nothing showed at all.
Done alot of skimming off the ground at about 1meter, was rock solid.

reflashing  .0900 might see work fine. I've also seeing a few cases where refreshing the firmware cleared odd issues.  

Yeah flew today, straight up was reporting weird altitude, one stage went into landing mode while still 40m or so above the ground but managed to "take off" again as soon as I heard the beeps.

So firmware didnt make any difference so ill probably knock it back one more version and try again.

On a better note my magpie buddy was there and I got even closer today ... he doesnt seem to care at all lol

Hello Chances, the VPS may not work well if there are too strong light or the drone is flying toward the sunshine. I'll attach the working conditions of VPS for your reference. Please keep us updated of the latest progress, thanks!

Hello DJI Susan.
Well I upgraded everything to the latest ... lastest firmware and latest Dji GO.
Have had 4 flights since with no problems what so ever.

Would the sun shining directly into the front of the quad make it think that its close to the ground even if its 50m + high?

Anyway so far so good... batteries are charging now and ill continue to test it until I trust it

Chances Posted at 2018-1-7 21:02
Hello DJI Susan.
Well I upgraded everything to the latest ... lastest firmware and latest Dji GO.
Have had 4 flights since with no problems what so ever.

Hello,

did you solved this VPS issue? My Spark has the same problem...

Sounds like a go version problem, go for version 4.1.15

MavSpa_user Posted at 3-3 09:37
Sounds like a go version problem, go for version 4.1.15

Hello, I’m using IOS... how can I downgrade the app version??

oke, IOS shoot be working