GPS Lock after takeoff

timmiser · Jul 11, 2014

Hey guys, just got my Phantom Vision+ this week and this is my first post in this awesome forum.

I do have a question: I very rarely can get a GPS lock prior to takeoff from my front yard... I live in a bit of a valley surrounded by hills so I don't think it is a problem with the Phantom. When I take off with the 4 yellows (No GPS mode), after the Phantom gets about 60 feet high, it will lock onto the satellites and turn green. My question is, what will happen if it goes to failsafe mode? Will it come back to that point 60 feet above my yard and just come straight down to land from there? I'm bit too afraid to try it out to see what happens but was just hoping someone might know?

Tim

sar104 · Jul 11, 2014

If you mean after it acquires > 6 satellites, then it will return to the point at which it achieved the position lock and set the home point (somewhere over your yard) and then descend until it lands.

Cocoa Beach Kiter · Jul 11, 2014

And as far as altitude during RTH, it will climb to 60 ft above the altitude it was at when it set home point or stay at the altitude it's at if higher. Return to home point and descend slowly until it lands

D_Tshudy · Jul 11, 2014

You could try the GPS foil mod described here:
viewtopic.php?f=27&t=19099

timmiser · Jul 11, 2014

Thanks team for your prompt replies. I will fly with confidence!

-Tim

Mori55 · Jul 11, 2014

Gps mod works great , just did it , well worth the time to do it.

timmiser · Jul 11, 2014

Yeah I'm definitely going to do that too. Can't hurt. I don't think my video recording affects satellites drops in my case, but I am interested in the better GPS reception received by those who reported that increase before turning on their video.

-Tim

jarrah31 · Jul 11, 2014

It's worth resetting your home position using the S2 switch (up and down 5 times) once you're up in the air and it turns green, that way you have extra reassurance of a home lock. See this vid from the excellent Simon Newton which explains how: https://www.youtube.com/watch?v=MJourEiJ77E

It may also be worth enabling NAZA mode for more control as you can still use the safe GPS Phantom mode. This page converted me to NAZA mode: http://www.pattayadays.com/2014/03/naza ... -2-vision/

An yes, do the GPS foil mod as it's made a world of difference for me and plenty of others: viewtopic.php?f=27&t=19099&start=70#p180517

Mako79 · Jul 11, 2014

sar104 said:
If you mean after it acquires > 6 satellites, then it will return to the point at which it achieved the position lock and set the home point (somewhere over your yard) and then descend until it lands.

+1

Mod below is %100 reversible except for the removal of the red stickers on the arms.
It will make your experience much more enjoyable.

https://www.youtube.com/watch?v=q31s6NDFUlA
viewtopic.php?f=27&t=19099

What i do in confined narrow spaces and low GPS:
Activate NAZA.
Left Toggle (s2) i switch from position 2-3, 5 times in quick succession. this locks the home point (this method doesnt reset my direction Course Lock, Pos 1-2 x 5 does the re/set course lock

Remember this can be done any time in mid flight.

Mako79 · Jul 11, 2014

double post

Mori55 · Jul 11, 2014

Just slice the stickers at the joints .

Mako79 · Jul 11, 2014

Mori55 said:
Just slice the stickers at the joints .

Thanks. I forgot to mention from a warranty (is there?) point of view.

Mori55 · Jul 11, 2014

Well after 30 days it doesn't matter.

Helveticus · Jul 11, 2014

sar104 said:
If you mean after it acquires > 6 satellites, then it will return to the point at which it achieved the position lock and set the home point (somewhere over your yard) and then descend until it lands.

Due to the unpractical place where I live (in a small, narrow valley where I have never had more than 4 sats) I always fly in ATTI (no GPS).

I do reset home point with S2 almost every time I fly, once the bird is high enough to get more than 6 sats, and can say that part works fine.

That said I never had to / tried to go in failsafe mode, yet... Problem is that, if I go to failsafe the bird will for sure loose GPS when going down in the valley...

Question is : What is going to happen once GPS is lost :?:
Will it go back to ATTI (without GPS) and drift in the wind while landing or will it stay more or less "hocked" on the few remaining sats and land more or less accurately :?:

sar104 · Jul 11, 2014

Helveticus said:
sar104 said:

If you mean after it acquires > 6 satellites, then it will return to the point at which it achieved the position lock and set the home point (somewhere over your yard) and then descend until it lands.

Click to expand...

Due to the unpractical place where I live (in a small, narrow valley where I have never had more than 4 sats) I always fly in ATTI (no GPS).

I do reset home point with S2 almost every time I fly, once the bird is high enough to get more than 6 sats, and can say that part works fine.

That said I never had to / tried to go in failsafe mode, yet... Problem is that, if I go to failsafe the bird will for sure loose GPS when going down in the valley...

Question is : What is going to happen once GPS is lost :?:
Will it go back to ATTI (without GPS) and drift in the wind while landing or will it stay more or less "hocked" on the few remaining sats and land more or less accurately :?:

I don't know the answer to that. I would guess that it would continue to descend in non-GPS mode, but there would be nothing to stop it drifting if it has lost its positional fix. Another situation where you want to be able to recover control as soon as the aircraft is back above you.

Dadcat · Jul 12, 2014

Helveticus said:
Question is : What is going to happen once GPS is lost :?:
Will it go back to ATTI (without GPS) and drift in the wind while landing or will it stay more or less "hocked" on the few remaining sats and land more or less accurately :?:

That's right. As soon as it sees fewer than 6 satellites in descent it behaves as if GPS doesn't exist. 5 satellites is the same as zero. That means it goes into ATTI and will drift with the wind while continuing the descent. Sar104 is exactly right. You should take control of the descent before that GPS loss occurs.

kymedic121 · Jul 12, 2014

If you are not gaining GPS until 60' then you are not getting a Home Lock until then. If you go in to RTH mode after gaining satellites then it will return to the point at which you achieved home lock. Once you go in to RTH she will climb 60' above the altitude you were flying and return to your home lock area and then descend. You may need to try do the GPS shield Mod to boost your GPS reception. This is very easy to do and there is a topic about boosting gps and a video to show you how to do it and its very very easy and everyone is saying that it works.

kymedic121 · Jul 12, 2014

Go check this out. Boost GPS reception. Getting good reviews on its performance and its super cheap and easy to do. viewtopic.php?f=27&t=19402

Helveticus · Jul 12, 2014

Thanks' for your responses guys' !

As for the aluminum foil shielding : I have purchased aluminum tape several days ago, right after the first positive feedback, and plan to do the surgery later today, will let you know how much it helps in my particularly bad spot

Helveticus · Jul 15, 2014

The "aluminum foil mod" solved my problem !

viewtopic.php?f=27&t=19099&p=186875#p186875

My advice : do not walk, RUN to a shop, grab some aluminum tape and DO THE MOD !