Return to home at night

[1bad]

Not really, except when pointing the camera down the strobes really light up the ground when about 30 feet agl or lower. I don't have front strobes but others say it doesn't bother the video (with strobes mounted on the front rotor arms). When I did mount on the front, the bugs made some unique effects and if close into some kind of structure like trees, the strobe is like a camera flash. I generally shoot forward for sunset pics and what not, so I mounted a white strobe on the bottom of my MP instead of a forward position. Air quality might also make a difference. Usually I'll grab a photo during dusk and return after dark. More back on topic, my quad seems to be able to hit the landing pad which makes me think the strobes are helping it hit the target when dark. I could be wrong.

Are those the firehouse brand, like 37 a piece?

 

[Greekislandlover]

I have tried night landings with my drone - a Mavic 2 Zoom. It used the GPS to get back to the start point, lowered itself and automatically turned the downward light on for precision landing. Worked fine.

 

[dronerdave]

Are those the firehouse brand, like 37 a piece?

Yeah the Arc-II's but they can be cheaper if you purchase a package deal.

 

[GB1Yorkshire1]

Hi guys I am trying to find out what will happen if I am flying at night and intiate return to home

It will return to home!
Assuming you calibrated the GPS and have the RTH height above any objects.
A Drone doesn’t know day from night

 

[Meta4]

Assuming you calibrated the GPS and have the RTH height above any objects.

There is no way you can calibrate the GPS

 

[GB1Yorkshire1]

There is no way you can calibrate the GPS

Correct I misspoke, however you can calibrate the internal GPS coordinates to return the Drone to its original position, in marine circles this is termed as calibrating the GPS though in reality you are obtaining a good 3D fix from the GPS to the internal memory on the Drone.
To calibrate the GPS you would need a very long ladder and a fast bike!
(in reality GPS systems are calibrated on each pass by the Gov.)

 

[Meta4]

Correct I misspoke, however you can calibrate the internal GPS coordinates to return the Drone to its original position, in marine circles this is termed as calibrating the GPS though in reality you are obtaining a good 3D fix from the GPS to the internal memory on the Drone.

This also sounds pretty confused.
You cannot "calibrate the internal GPS coordinates to return the Drone to its original position"
The drone will record its homepoint location and return there without any intervention.
Perhaps you meant something to do with resetting the homepoint to return to a different location?
Or maybe something about position averaging (?) but that's irrelevant to drone flying anyway.

The reference to something marine is also confusing.
I've used GPS professionally and in a marine environment for >20 years and can't understand your reference.
The drone's GPS should always be giving a good 3D fix without you doing anything.
No-one ever does anything to calibrate a consumer GPS and there is no need to.
Consumer GPS is quite accurate enough without messing around with it.

 

[LazerMan]

I find it absolutely amazing how many people post answers to questions, that they have no idea what their talking about.who are they trying to impress all they do is make themselves look foolish.Whats that saying , better to stay quite and let us think your dumb then to open you mouth and remove all doubt.

 

[Greekislandlover]

I find it absolutely amazing how many people post answers to questions, that they have no idea what their talking about.who are they trying to impress all they do is make themselves look foolish.Whats that saying , better to stay quite and let us think your dumb then to open you mouth and remove all doubt.

Agreed.

Going back to the original question, GPS doesn't care if it's light or dark. It might have a limited number of satellites if you have taken off from a concrete canyon, or in certain weather conditions (possibly). So assuming you have enough of a GPS signal, the RTH location and take off height is recorded, and that's where it will come back to - night or day.

The only difference between a landing at night is that the Mavic 2 series and the Mavic Air 2 (not sure about the MM) have an auxiliary light on the bottom that comes on automatically to aid precision landing.

So what happens on a night time RTH is that the drone will do a perfectly normal RTH guided by GPS, and as it lowers down it will turn the light on towards the end of the landing to aid precision landing.

If it doesn't have a light you may need to do some manual adjusting as to the exact spot as the effectiveness of the visual sensors may be low. But as GPS also calculates altitude, it knows where the ground is, and will slow down as normal to land smoothly.

You have to accept with all landings that it doesn't come home to exactly the same spot, although it is pretty gosh-darned good. Some manual control may be required. For example, I use my local park as my test ground, and by the war memorial there is a series of steps possibly 2 metres by 3 metres. If I have taken off from near the edge of a step I might need to correct where I want it to land fractionally. That's perfectly normal - even in broad daylight.

 

[Meta4]

It might have a limited number of satellites ... in certain weather conditions (possibly).

Weather makes no difference to GPS

But as GPS also calculates altitude, it knows where the ground is, and will slow down as normal to land smoothly.

If it is too dark for VPS to sense teh ground, the drone has no way of telling how far it is to the ground.
GPS cannot assist with that.
The drone on autolanding would just descend until it can descend no further.

 

[Greekislandlover]

Weather makes no difference to GPS

If it is too dark for VPS to sense teh ground, the drone has no way of telling how far it is to the ground.
GPS cannot assist with that.
The drone on autolanding would just descend until it can descend no further.

Hi,

I only put weather down as a possible as there are some that think it does. However, my practical experience is that my drone has never had a problem locating many satellites. The only time was when I was literally at the bottom of a canyon!

GPS does calculate height. Therefore it will know where it took off from in terms of lat, long and height.

Altimeter - Wikipedia

en.wikipedia.org

My comments on how the landing works with or without the light is based on my practical experience of doing just that. I have done some night time time lapses with both my Spark and Mavic 2. The Mavic 2 has an auxiliary light, the Spark doesn't. The timelapses were taken originally with the Spark, and I went back to the same spot when I upgraded. The Spark would land certainly within a meter of the take off point, slowing down towards the landing and the Mavic 2 behaved the same way apart from the light. But as the take off was from smooth tarmac, both drones had trouble with precise landing point, but no problem with knowing where the ground was and to slow down.

Also, as I said you need to be aware when landing and be prepared for manual adjustment on any drone at any time of day.

Now it's off to work, whilst most of my workmates are still on furlough at 100% pay. Bitter???? MOI???

 

[Meta4]

I only put weather down as a possible as there are some that think it does.

Although it might occasionally be suggested, it's wrong.
GPS is designed as an all-weather navigation system

GPS does calculate height. Therefore it will know where it took off from in terms of lat, long and height.

Your drone does not use GPS to provide height information for landing.
GPS cannot provide height above ground information anyway and that level of complication is not necessary.
It can land perfectly well without any height information, just as DJI drones did for years before downward sensors were introduced.

 

[SkyeHigh]

Although it might occasionally be suggested, it's wrong.
GPS is designed as an all-weather navigation system

Your drone does not use GPS to provide height information for landing.
GPS cannot provide height above ground information anyway and that level of complication is not necessary.
It can land perfectly well without any height information, just as DJI drones did for years before downward sensors were introduced.

The AC uses its internal barometric pressure sensor to measure height above AGL. It is supplemented by the downward sensors for greater precision. Landing at night makes no difference to its ability to determine its height... but if you want to land accurately from where it took off the downward sensors are required as would be the additional ‘landing’ lights on the Mavic 2’s.

 

[umanbean]

The AC uses its internal barometric pressure sensor to measure height above AGL.

Technically, the barometer measures altitude AGL at the take off position. It has no sensors or other ways to measure height AGL when flying around.

 

[SkyeHigh]

Technically, the barometer measures altitude AGL at the take off position. It has no sensors or other ways to measure height AGL when flying around.

Sorry, but you are incorrect there. The barometer measures height AGL all the time on the ground and in flight. It has no other accurate way to determine height AGL. It is no different to any aircraft private or commercial. The only difference to large commercial aircraft they have the benefit of ground facing radar.

 

[umanbean]

Sorry, but you are incorrect there. The barometer measures height AGL all the time on the ground and in flight.

We'll see. Maybe someone will chime in who can explain it better than I did.

 

[Meta4]

Sorry, but you are incorrect there. The barometer measures height AGL all the time on the ground and in flight.

The barometer does not measure height above ground level all the time on the ground and in flight.
It measures height above the level of the home point.
Fly your drone from a hill or cliff top and see how yours does at measuring height AGL all the time in flight.

 

[SkyeHigh]

The barometer does not measure height above ground level all the time on the ground and in flight.
It measures height above the level of the home point.
Fly your drone from a hill or cliff top and see how yours does at measuring height AGL all the time in flight.

That is correct but not the meaning of my post. What I’m saying is the barometer is always active, it doesn’t stop using it once in the air. It references it’s reading at the take-off location but it is constantly measuring while in flight and subtracts its present pressure reading from its take-off point to determine its relative altitude.

A lot of people appear to assume GPS is used in flight for altitude but it isn’t anywhere near accurate enough.

Many people also believe their smartphones use GPS for altitude but they have the same form of MEMS barometric pressure sensor as our drones.

 

[old man mavic]

with regards to RTH accuracy,i can confirm that the difference between using precision landing and not on my MPP is amazing ,if the tick box is clicked for precision landing, then the drone ,even if it windy will land back on the take off mat with uncanny accuracy if not then it can be anywhere within a 3 ft radius of the mat,although i very rarely use RTH preferring to fly manually back home, i did do a comparison test early on in my ownership of the MPP ,to see how good the precision landing was, i still tick the box when i take off in case i end up with an issue that would trigger a auto RTH i think it was a good thing to have on the MPP and its a shame that they discontinued it on the M2P and zoom although i know its there as long as you remember to go up to 25 ft before you fly off

 

[SkyeHigh]

with regards to RTH accuracy,i can confirm that the difference between using precision landing and not on my MPP is amazing ,if the tick box is clicked for precision landing, then the drone ,even if it windy will land back on the take off mat with uncanny accuracy if not then it can be anywhere within a 3 ft radius of the mat,although i very rarely use RTH preferring to fly manually back home, i did do a comparison test early on in my ownership of the MPP ,to see how good the precision landing was, i still tick the box when i take off in case i end up with an issue that would trigger a auto RTH i think it was a good thing to have on the MPP and its a shame that they discontinued it on the M2P and zoom although i know its there as long as you remember to go up to 25 ft before you fly off

Absolutely. I’m very pleased DJI added Precision landing in the end for the M2P’s. My experience so far has been very, very precise. Even with a stiff wind, it will take a bit longer but it still lands right in the middle of the mat.

I did a test a few weeks ago, which pleasantly surprised me. Took off, climbed to approx 8-meters briefly to get optical reference then flew 100-metres away. Next I moved the landing mat 3-metres to the right and hit the RTH button. What happened?

My M2P climbed to its RTH height, flew back above the take-off point and dropped to around 5-metres and paused. Then it moved right over to the landing mat and did a bullseye landing. The optical assistance definitely works with a strong contrasting orange mat and green grass.