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Zero elevation at home point.

Discussion in 'Phantom 2 Vision Discussion' started by pounder35, Oct 14, 2015.

  1. pounder35

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    Using Litchi on my P2V and trying to do waypoint flying I've noticed that my altitude at waypoints is much lower than I intend. Playing around I find my altitude at "home" where I set the GPS and compass shows about 29 feet. When I reach waypoint one which I have set for 100 ft. I'm flying around 42 ft. Even doing the math to compenste for my starting being 29 ft. it's still off. 100 ft. - the 29 ft. should have the bird at 71 ft. I'm flying in an open field with a few trees and flying lower than where I set my waypoints could be a problem. I'm trying to accurately determine what altitude to set. Of course I could set waypoints to avoid the trees but in the future I'd like to know exactly how this works. Can I manually set my "home" position to zero and be able to count on the waypoint altitudes above the "home" altitude to be accurate?
     
  2. KenW

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    Altitude is measured by barometric pressure and GPS signals. Neither are very accurate. Barometric pressure varies all over the place. For GPS altitude, get out a tracker on your phone (like My Tracks) and record a 1 mile walk. Walk out and back on the same route. You will find little resemblance in the out vs. back altitude trace.

    I always leave a 50' cushion in my groundstation flights, particularly if the flight involves a reduction in altitude. On my first GS flight I had a WP at 150' that reduced to 35' over a garden area in a park. I barley cleared the 6' chain link fence around it. Big pucker when the bird was 700' away and I couldn't see what was going on.
     
  3. pounder35

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    I had a few trees I wanted to clear of so I thought I set the altitude plenty high. I also laid out my waypoints to avoid the trees but after a few crashes I'm a little gun shy of obstacles. I have a terrible time seeing the screen on the LG 8.3 tablet and my Samsung Galaxy 5. I've ordered an shade but for now I just have to watch my Phantom and ignore the desire to fly FPV. Running the Litchi app I keep getting the warning that the wifi is disconnected. This starts within a hundred yards out in an open area and the warning repeats a few times a minute. I might try one of the antenna modifications on YouTube. I'd also like to add a 2 or 3 axis gimbal. By the time I do all the mods I would better off buying the P3. ;)
     
    jmf4397 likes this.
  4. KenW

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    When flying around trees, i set min altitude at 150'.

    For WiFi connections, make sure you are flying in Airplane Mode (on your phone) with WiFi enabled. Bluettoth in particular, and the phone radio can interfer with WiFi signals. I get 200' with wirplane mode off, and 1500' FPV range with it on.

    If you want to fly FPV, get a google carboard headset. I got mine for $20 from AliExpress.com. Litchi has a VR mode that is compatible. There are currently issues with head tracking, but the develope is working on it (I know because he is sending me nightly builds to try out fixes). If you turn off head tracking for now, and rotate the cam full up before enabling VR, it is prettty cool. You will look like a dork, but it is worth it. You will have much more confidence in your flying. You won't have visibility to anything other than your phone's screen so you do need to be careful.
     
  5. pounder35

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    Thanks for the info. I'll be flying this afternoon and try those suggestion. I have Bluetooth normally on and haven't tried the Airplane mode. I'm probably getting signal overload with everything running at once. I'll post an update this evening.
     
  6. pounder35

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    I've looked at the products by Durovis and Freefly. More expensive but look a lot more durable. I did a quick test flight after putting my phone into airplane mode and my tablet into airplane mode but with wifi on. I didn't get any warnings but my video cut off and the video and still shot buttons cut off. I've been playing around with it at the house and seems to be working OK now. I'm going to make another trip to our flying field and make another run. Fortunately it's only a few miles away.
     
  7. pounder35

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    I made a few more flights yesterday and my wifi worked fine after following KenW's suggestion. Since I was using the LG Tablet I set my Samsung Galaxy to airplane mode. No wifi or Bluetooth. Then set the tablet to airplane mode and turned on only wifi. It worked perfectly. Thanks KenW.
     
  8. KenW

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    My pleasure. It comes up so often that it would be a sticky post in the forums.
     
  9. pounder35

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    I should have used the "search" function but I'm still trying to feel my way around the forum. Thanks again for pointing out what should have been obvious.
     
  10. KenW

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    Not obvious. It took me four flights to figure out what was going on. It started when I simultaneously upgraded my phone and my reange extender. I beat my head against the wall.
     
  11. pounder35

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    Speaking of range extenders I'm considering doing that. I've watched a few YouTube videos and the half dome antennae looks like a good option. The helical extenders are a little bulky. I'm not sure of my controller range since the furthest I've flown is less than 1/2 mile.
     
  12. KenW

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    The most I have don e is the RE700. I would like more FPV range, but realistically, 1300 feet is enough for me.
     
  13. pounder35

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  14. KenW

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    There are dozens of even cheaper ones on Aliexpress.com. That is where I got mine. Optics could be better, but the price was right ($20 delivered). It does take about 3 weeks coming from China.

    flight control in the headsets is much better. You just need to be ready to have your kids call you a dork.
     
  15. pounder35

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    I checked tracking and it said delivery should be Friday. I hope it works out because even with a new shade it's still hard to see the screen on my tablet. I added an anti-glare screen cover and a nice wraparound shield and in the middle of the day it's better but still not what I'd like to see. Early morning and late afternoons should be OK. I'm going out about an hour before sunset to try again. I had a little glitch with waypoint flying earlier. I had an outer waypoint and a return almost as overlapping lines and it seems like that caused a problem even though there were two more waypoints between those two. It's like the Phantom came to an intersection and didn't know whether to turn left or right. Right being home and left being back to waypoint 1. At least I'm having fun going insane figuring this stuff out.