lost mavic pro

[JDawg]

If you take off without recording a home point then you will not return to where you expect if you are disconnected.

"If you took off at night there is a danger that your RTH point was not recorded. "

I was curious about this too?

 

[Meta4]

If you take off without recording a home point then you will not return to where you expect if you are disconnected.

But as I pointed out above, he would record a home point very close to where he started anyway.

 

[kidroc]

How do you figure that?
The GPS sats stay up in the sky even when the stars come out.

Either that's a typo or you need to check again.
This is what your manual says:
Smart RTH, Low Battery RTH, and Failsafe RTH follow this procedure:
1. The aircraft adjusts its orientation.
2. a. If the aircraft is further than 20 m from the Home Point it ascends to the pre-set RTH attitude and then flies to the Home Point.
b. If the aircraft is between 5 m and 20 m from the Home Point it flies to the Home Point at the current altitude, unless the current altitude is less than 2.5 m, in which case the aircraft ascends to 2.5 m and then flies to the Home Point.
c. If the aircraft is less than 5 m from the Home Point it lands immediately.
3. The aircraft lands and stops its motors once it reaches the Home Point.

If he launched before recording a home point, the Mavic would record a home point when it got a GPS location fix, and that would have been very shortly after launching.

Flying at Night is no different than the day GPS doesn't care.. Metas right on as usual..

 

[Splashy]

I may be wrong but I believe that the home point is registered using both GPS and visually using the camera. That is why you are recommended to ascend to 10m to record your home point. In the dark you are relying purely on GPS. If there are insufficient sats locked then your home point accuracy could be much more than the 3m accuracy. If for example the Kp value is high then GPS accuracy may be very poor.

There has been mention that high winds may affect the flight but surely if the GPS lock is strong then the drone will compensate for the wind. IF the wind strength was greater than the max air speed of the drone then it would be effectively blown away since it would not be able to compensate enough for it to hold position.

Therefore the Kp value may be a consideration (maybe look it up for the night in question).

Kp Value
Impact on Drone Operations*
1–3 — Safe, unlikely to lose noticeable accuracy
4–5 — Safe, slight chance of accuracy loss
6 — Safe, up to 5% accuracy loss
7–9 — Avoid operating, potential for loss of GPS connection and radio signal interference

 

[Meta4]

I may be wrong but I believe that the home point is registered using both GPS and visually using the camera. That is why you are recommended to ascend to 10m to record your home point. In the dark you are relying purely on GPS. If there are insufficient sats locked then your home point accuracy could be much more than the 3m accuracy.

The home point is registered with GPS alone.
The launch spot can optionally be recorded with optical technology to facilitate precision landing.

There has been mention that high winds may affect the flight but surely if the GPS lock is strong then the drone will compensate for the wind. IF the wind strength was greater than the max air speed of the drone then it would be effectively blown away since it would not be able to compensate enough for it to hold position.

Being caught in strong winds are a common cause of problems (see Mavic Pro FLY AWAY - Help DJI not helping for a recent example)
The OP hasn't shown enough interest to post any flight data which would show if wind was a relevant factor.

Therefore the Kp value may be a consideration (maybe look it up for the night in question).

In 4 years of flying DJI drones and reading drone forums, I still haven't seen a case where the KP index had any effect on any drone.
I think it can safely be discounted.

 

[m0j0]

500mtrs straight up broke guidelines on altitude in a lot of countries.

True but to be honest it shouldn't just fly away because it is 500 meters up.

As the Mavic is limited in software to 400ft you knew enough to hack the software but not enough to keep your drone.

Just wrong. Completely wrong.

We need the flight logs!!

Why the anger? How likely are others to come in here and discuss their issues if they get attacked? How do we educate other posters when people won't report their errors for fear of attack? If he want's to figure out what happened he will post the logs. Your aggressive post will be more likely to result in a total disconnect from the OP. Nobody benifits from that.

 

[m0j0]

If you took off at night there is a danger that your RTH point was not recorded.
.

WTH - So now we are saying you can't set RTH at night? Why? Please elaborate.

Jeebus Mari and Joseph people. If you are going to be making comments condemning someone can you at least make your own comments accurate. Taking off at night has nothing to do with setting RTH.

 

[swings16]

500mtrs straight up broke guidelines on altitude in a lot of countries. I’d bet that you had no idea of wind speeds at that height and I’d guess that it lost signal due to incorrect antenna orientation then got blown away when RTH settings couldn’t cope with the wind speed. As the Mavic is limited in software to 400ft you knew enough to hack the software but not enough to keep your drone.
We need the flight logs!!

400 ft. in HEIGHT ? It May be a dumb question but why would it matter in height and not in the LENGTH away ? Why the difference ?

 

[Meta4]

400 ft. in HEIGHT ? It May be a dumb question but why would it matter in height and not in the LENGTH away ? Why the difference ?

It's very common to lose signal if you fly straight up and high because it's impossible to have good antenna geometry when you do that.

 

[DanMan32]

That's when you put the antennas straight out so that they radiate up.

 

[msinger]

That's when you put the antennas straight out so that they radiate up.

Yep! Even though, that's a location where the signal will be the weakest. So, you could still lose the connection even if the antennas are pointed properly.

 

[m0j0]

I may be wrong but I believe that the home point is registered using both GPS and visually using the camera.

Yes, you are wrong. RTH is set by GPS and GPS alone. The newer platforms use photographs to identify a "precision landing point." That feature would be unavailable if the landing area is dark but... RTH is pretty accurate even without the precision feature. I flew all the time with my older platforms and they would pretty routinely land within a few feet of where I took off.

In the dark you are relying purely on GPS. If there are insufficient sats locked then your home point accuracy could be much more than the 3m accuracy. If for example the Kp value is high then GPS accuracy may be very poor.

No.. if you don't have enough sats your bird will not use GPS and will main in ATTI mode. That means it has no GPS lock and ... No Home Point. That is why one of the most important preflight checks is to wait for the Green light. Followed by the audible prompt for you to check it in your map.. Pretty critical before taking off.

If for example the Kp value is high then GPS accuracy may be very poor.

There has been mention that high winds may affect the flight but surely if the GPS lock is strong then the drone will compensate for the wind. IF the wind strength was greater than the max air speed of the drone then it would be effectively blown away since it would not be able to compensate enough for it to hold position.

Therefore the Kp value may be a consideration (maybe look it up for the night in question).

Kp Value
Impact on Drone Operations*
1–3 — Safe, unlikely to lose noticeable accuracy
4–5 — Safe, slight chance of accuracy loss
6 — Safe, up to 5% accuracy loss
7–9 — Avoid operating, potential for loss of GPS connection and radio signal interference

Hmmmm... I've been flying for a long time, hundreds of flights. KP Value has never been something I considered. I don't think anyone in my years of flight have ever provided solid information that KP Value was a factor that should be taken into account. I don't recall ever seeing it mentioned in any manual i have read either.

 

[swings16]

Luckily i have never lost a signal (in my 15 ,16 flights)

i never adjust my Antennas...i point them UP and so far i have never lost a connection (i would be very upset if i did as i am constantly concerned with the possibility of a fly away or a loss of signal while flying over one of the most populous parts of our country..(NYC ) and the harm that my flying might cause IF this happened..so far,ALL flights have been flawless and for that,i am grateful..

 

[Splashy]

If you are flying vertically up then you should have your antenna parallel to the ground. Having them pointing up could definitely result in a loss of connection.

 

[DanMan32]

Yep! Even though, that's a location where the signal will be the weakest. So, you could still lose the connection even if the antennas are pointed properly.

What makes you say that?
Signal radiates perpendicular to flat sides of antennas, so normally you point them up to radiate mostly out, and point out to radiate mostly up (and down).

 

[sar104]

What makes you say that?
Signal radiates perpendicular to flat sides of antennas, so normally you point them up to radiate mostly out, and point out to radiate mostly up (and down).

The receiving antennas on the aircraft, however, are still in the wrong orientation.

 

[msinger]

What makes you say that?

See @sar104's comment above.

 

[DanMan32]

That makes sense, but having RC antenna in less than ideal orientation for situation only makes it worse
At 400ft, probably not much of a difference anyway.

 

[BossBob]

400 ft. in HEIGHT ? It May be a dumb question but why would it matter in height and not in the LENGTH away ? Why the difference ?

Wind speeds at 400 ft can be hugely different from wind speeds at 1500 ft, different enough that the drone might not be able to overcome them and RTH.
As for antenna orientation, I liken the pattern that they radiate to a ring doughnut with the antenna in the hole. If the OP had the antenna pointing straight up and he flew the drone straight up 500 metres into the lowest signal strength area. If the wind speed at that altitude was too high the drone would have drifted down wind out of control. If the home point hadn’t been recorded correctly, the drone would have made off (if it could) to whatever homepoint it had in its memory.
It’s all just speculation. If the op stopped just watching us bitching at each other and posted the logs of the flight we’d find out what happened.

 

[dannybgoode]

A quick note on the KP index (and note I am an advanced licence holder ham radioist so this is something I spend a lot of time monitoring).

A high KP index can certainly affect radio wave propagation however it has a much greater effect on long distance HF communications and other radio communications that rely on the ionospher for its propagation.

It has very little effect on LOS (in the radio wave sense and not necessarily visual LOS) transmissions. A really massive solar storm may cause issues to drone flying but that would be the least of your worries given what else would be taken out.

Of course when the Earth’s magnetic field flips (which it will at some point and no one knows when) that will be really entertaining and not just for drone pilots .