Launch in atti, fly in p

[trmcconn]

Planning to launch in a clearing in a dense forest. Probably I won't be able to get enough satellites at launch for P mode, but once above the trees there should be plenty visible. Will my P3 Adv switch to P mode as soon as enough satellites are visible ? (guessing it will.) What about the home point? Will it record the point directly under where it is when it enters p-mode?

Flight plan is to launch in A mode, go up to 100 feet and hover, switch to p mode (actually, f mode), then fly a fixed heading while filming. Since trees may block visual of the drone when it is downrange, proper recording of the home point is vital in case I need to RTH with no visual contact.

 

[With The Birds]

It will enter P-Mode when sufficient satellites are acquired.

If you need the home point to be in a certain spot you will need to hold station in ATTI mode until P mode is acquired and home point recorded.

I think you will be surprised how many satellites you do get on the ground. The biggest issue might be the size of the clearing and how accurately the AC might return to the home point.

 

[ROD PAINTER]

If you take off in atti mode, you may have to manually switch to p mode. Also, you must fly vlos (visual line of sight). FAA regulations require you to maintain visual contact with your drone at all times. Personally I would not take off in atti mode especially if you are close to this forest you are talking about. Someone please correct me if I'm wrong if the P mode will auto kick in when enough satellites are acquired as I have never taken of in atti mode.

 

[With The Birds]

If you take off in atti mode, you will have to manually switch to p mode. It doesn't do it for you. Also, you must fly vlos (visual line of sight). FAA regulations require you to maintain visual contact with your drone at all times. Personally I would not take off in atti mode especially if you are close to this forest you are talking about.

Thank you for pointing that out- on a read again it was clear the OP intended to launch in ATTI mode. I had wrongly assumed launching in P without sufficient satelites (not with the switch in the ATTI position). My money is on being able to launch in P mode.

 

[Fly Dawg]

Personally I would not take off in atti mode especially if you are close to this forest you are talking about.

I think his reasoning was self explanatory. Taking off in ATTI is just fine, as long as you are proficient with the controls. Agreed, that once above the tree tops, a manual switch to P-GPS would be required, assuming the op wishes to use such. If taking off in ATTI mode, if the aircraft is powered up this way, will not record a home point. However, the switchover to P-GPS will, assuming sufficient satellite acquisition at that point. Personally I would try P-GPS first, once the home point is recorded then launch or if not, climb to altitude where it will. That would require testing and would depend on the launch point.

 

[Meta4]

Almost there.
It doesn't matter what position the flight mode switch is in.
The Phantom will record a home point when the GPS receives its first good position fix.
If somehow the homepoint isn't where you would want to descend, just hover above the window and reset home to the current location of the Phantom.

 

[Fly Dawg]

The Phantom will record a home point when the GPS receives its first good position fix.

Correct, but this depends on the position fix. As I mentioned, above the tree tops, if we are talking a lot of canopy cover. It will not record a home point if you take off in any mode, prior to acquisition. Maybe I misworded previously.

 

[With The Birds]

Almost there.
It doesn't matter what position the flight mode switch is in.
The Phantom will record a home point when the GPS receives its first good position fix.
If somehow the homepoint isn't where you would want to descend, just hover above the window and reset home to the current location of the Phantom.

Absolutely- thats it! My point of clarification was that there is no need to have the switch in the ATTI position at launch. Simply fly up and hold station until home point recorded (assuming GPS fix cannot be acquired on the ground).

 

[solentlife]

Think some have forgotten that the GPS unit on the AC works at all times. Regardless of switch position. The difference is whether the unit can get signal from enough sats to know its position and record home point.
The next point is whether the AC uses the GPS info - that is where the switch makes its effect.

Interesting that if you check the manual Pro or Adv ... the same : Page 11 Flight Mode .... where it says that as long as Home Point has been recorded and it has GPS lock ... even with ATTI - if you lose signal - it will return.

I know its obvious - but of course the real worry is the RTH and being able to see the AC to cancel it before it tries to land through the trees !!

Another issue is the control and video signal ... 2.4 is notorious for its LoS connection and reduction of signal with obstacles. If the tree cover is dense enough as the AC flies away - you could lose signal far quicker than if in open area.

Nigel

 

[trmcconn]

Thanks for all the great advice. It turned out gps was good enough for a P mode launch. I wanted to take some footage of an interesting pattern of clear-cut alternating with uncut swaths in a state forest that was logged about 5 years ago. I had to launch in one of the clear cut swaths that was about 100 feet wide and 1/4 mile long. Unfortunately it was heavily overgrown with blackberry bushes about chest high so I first had to mat down a circular area to launch from. I did a poor job on this and the circular area was barely big enough for the propellers, but it got up ok. Uncut trees were about 90 feet high so I flew at 120. Once above trees I switched to f mode and flew along a fixed heading. When it was about 1000 feet downrange I chickened out and brought it back (worried about losing signal through the thick forest.) Given the overgrown conditions it's lucky I didn't have to take off in ATTI.

 

[solentlife]

Well done ...

An item I carry is a thick hessian backed carpet square ... cut to fit inside my pack ...

Any rough or long grass area etc. - I can lay that for a pad. I did try lightweight carpet - but downwash caused it to lift and move ...

Another is a folding picnic table ...

Nigel