Flying indoors, Vision system assistance

[Ralph thompson]

The M2P manual states that "The Vision System is only effective when the aircraft is at an altitude of .5 to 50 meters" Later it states that "the vision system may be affected if the aircrafts altitude is above 33 feet (11 meters)". I have to video a scene in a fairly limited indoor space with a tiled floor (different colored tiles so fairly texted) and would like to fly up to 50 feet (15 meters). Obviously no GPS signal. Do you think the vision system will provide lat/long stability and what surprises might I expect to see please?

 

[Deleted member 103366]

Uuuuum if I take off before it has the necessary number of satellites for a GPS lock the maximin height is severely limited when the vision system is active, you might want to have a look at page 57 of the manual.
I can't remember if you can disable the downward looking sensors by choice but if you can then you will surely be in ATTI mode and need to be careful.

 

[Mazdaman323lx]

You can't fly that high in atti mode . There's a max height of about 3 meters in atti mode - at least with my MA-2 anyway

 

[Ralph thompson]

Im just quoting the manual, one place it says 50 meters, another place 15 meters. Big difference. Theres no altitude limit in OPTI or ATTI mode. I've flown up from between trees with as few as 8 satellites, no problem, once your above the trees, you pickup more satellites. The downward visual sensor is very useful, it would be great if it extended to 50 meters.

 

[Not A Speck Of Cereal]

I think the 33' foot limit just means that Visual Positioning isn't good beyond that, but VPS doesn't really give you GPS like position lock anyway, as far as I know. I would always expect to be flying by stick in ATTI mode. Drift will happen with even the slightest air movement, so if you are not familiar with flying in ATTI mode, you could lose control.

The thing that bothers me with the M2P/Z is that there is no ATTI position on the switch. By default, it only goes into ATTI when it loses GPS lock. The main thing that bothers me about that is if you're in a situation where it gets borderline satellites and goes in and out of ATTI. That possibility would always make me nervous.

Instead, I've done the ATTI hack, over-riding the SPORT position on the flight mode to do full time ATTI. It shuts off GPS receiving, so you're 100% ATTI. Search the forums for topics with ATTI in the topic title to find threads on how to do the hack, if you're interested. It's not really a hack, since you use DJI debug mode to change the parameters to make this happen (there is no hardware modifications), but it is not DJI sanctioned either.

Chris

PS: If the Mavic Air limits one to 3 meters in ATTI, that would be a big pass for me (no thanks to that model).

 

[Ralph thompson]

Thanks Chris, I've flown ATTI many times, I have (but don't use anymore) a Phantom version 0 and Inspire, both have ATTI and used it to practice many times. My concern is like yours, in a shaded area having the control system clicking in and out of GPS mode is a concern knowing that when things go haywire its hard to think straight the drone can quickly slip away from you.
I'm guess in the hack gets wiped out when you update the firmware.

 

[inno]

The M2P manual states that "The Vision System is only effective when the aircraft is at an altitude of .5 to 50 meters" Later it states that "the vision system may be affected if the aircrafts altitude is above 33 feet (11 meters)". I have to video a scene in a fairly limited indoor space with a tiled floor (different colored tiles so fairly texted) and would like to fly up to 50 feet (15 meters). Obviously no GPS signal. Do you think the vision system will provide lat/long stability and what surprises might I expect to see please?

Hi Ralph, to help clear this up for you. The mention of .5 to 50m is the optimal operating range for all the sensors. It does not mean that all the sensors can detect up to that range. The range the sensors can sense is two fold. Detectable Range, meaning the sensors can start picking up an object and Precision Measurement Range is where it can determine approximate distance from the object. See the spec page below for the M2P below.

I have flown my drones Phantom 3 Adv, Mavic Pro, M2Z, MA2, MM2, and Spark at one time or another in a Home Depot warehouse where I worked. Except for my DJI FPV. The building has a 40' ceiling, grey concrete floors (no contrast for downward vision sensing for position), and a ton of steel shelving. So NO GPS or compass for that matter. However the FOV has a wide enough viewing angle that it picks up objects to help hold position, such as racks and other things of product on the floors.

also below, is a short 25sec video and a pic shot with the DJI Spark as an example of the stability. Only advice is to try and stay away from the HVAC vents. They are big blow hards and you need to be ready in case you fly past one of their vents.

Hope this helps, Happy and Safe flying
inno

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Mavic 2 Pro/Zoom manual page 63

 

[Ralph thompson]

Thanks inno, yr first video is private.
I think the compass (independent of GPS) would still function as of course the IMU. The concern is that it could get affected by any metal like shelving & cause a misalignment of the compass and the IMU Which I heard could cause control problems. But you had no issues, no radio interference etc? My concern is being heads down filming & not seeing a drift.

 

[Not A Speck Of Cereal]

Thanks Chris, I've flown ATTI many times, I have (but don't use anymore) a Phantom version 0 and Inspire, both have ATTI and used it to practice many times. My concern is like yours, in a shaded area having the control system clicking in and out of GPS mode is a concern knowing that when things go haywire its hard to think straight the drone can quickly slip away from you.
I'm guess in the hack gets wiped out when you update the firmware.

I've had one firmware update on the M2P and the hack survived it.

 

[Meta4]

I think the compass (independent of GPS) would still function as of course the IMU.

Of course your compass would be functioning.

The concern is that it could get affected by any metal like shelving & cause a misalignment of the compass and the IMU

You would have to be closer than 4 ft to steel shelving before it had any effect on the compass, and it would never have any effect on the IMU.

 

[inno]

Of course your compass would be functioning.

You would have to be closer than 4 ft to steel shelving before it had any effect on the compass, and it would never have any effect on the IMU.

agreed, however flying through the aisles of the store do affect the compass, so i just ignore but it does not affect controlled flight. You just have to stay with the drone (walk behind), no looking away. When in the aisles you only have less than 3 feet to either side of the drone then nothing but steel shelving. In the two main aisles that cross the store they are at least 12' wide and no issues

Thanks inno, yr first video is private.
I think the compass (independent of GPS) would still function as of course the IMU. The concern is that it could get affected by any metal like shelving & cause a misalignment of the compass and the IMU Which I heard could cause control problems. But you had no issues, no radio interference etc? My concern is being heads down filming & not seeing a drift.

Try the video now. I think it may work. Really the first time using YouTube for others to see other than myself.

 

[inno]

Thanks inno, yr first video is private.
I think the compass (independent of GPS) would still function as of course the IMU. The concern is that it could get affected by any metal like shelving & cause a misalignment of the compass and the IMU Which I heard could cause control problems. But you had no issues, no radio interference etc? My concern is being heads down filming & not seeing a drift.

I was always less than a 100' in the main aisles and no more than 25' in the the product aisles. Had no issues with connectivity.

the only issue that could have been was the air flow from the HVAC systems. But coming from so cal, and flying fixed wing in santa ana wind conditions you learn to fly as we call it now ATTI, no help from the software.

I've got a lot of video from inside the warehouse flying the aisles and it's a learned skill. Yes, VPS helps but you still need to watch your drone as well as the screen. Practice and time, and you'll get it,

ps
you should use propeller guards as well, as I've hit/bumped the rack many times

 

[Rich QR]

I think the compass (independent of GPS) would still function as of course the IMU. The concern is that it could get affected by any metal like shelving & cause a misalignment of the compass and the IMU Which I heard could cause control problems.

Compass issues due to being near magnetic material can cause serious stability problems, but I believe this is only a real problem when you have GPS. Accurate heading information is required to convert a drift detected by the GPS into an action for the drone to take.

For example, if the GPS says you're drifting to the north, the computer should command a rearward motion if the drone is pointed north, but it should command a forward motion if the drone is pointed south. If the drone has a seriously wrong idea about its heading, it can command a "correction" that sends the drone off in the wrong direction, prompting the GPS to see a further position error, thus causing the computer to try a further "correction" that makes things worse, etc.

The vision sensors don't have this problem, because they directly see the drone's movement in terms of forward/back/right/left. If the vision sensor says the drone is drifting left, then the computer can command a correction to the right, without consulting the compass (or the IMU's heading indicator).

 

[Deleted member 103366]

would like to fly up to 50 feet (15 meters). Obviously no GPS signal.

Why not take the drone out of doors to a wide open space, shield it if you can to minimise its exposure to gps signals prior to power up. Power it up once there and take off ASAP, before the drone gets it required compliment of GPS satellites, and see how high it will go?
That might save a lot of debate.
Mine seems to be limited to maybe 15ft, I have never taken note of the actual figures showing on the display. Once it has its required compliment of GPS satelittes it can go higher.
From my flying the downward looking vision sensors seem limited to within around 10m of the ground. I suppose objects stood on the ground / floor might increase that height but I haven't really investigated that.

 

[inno]

Hey Ralph, you should not have any real issues. Just make sure when you fire up your drone and before take, that there are no issues being displayed, ie, compass or imu issues, you can also check this from the menu system. if there are, just move and re-start your drone from a different location and then either pickup or fly your drone to the spot you want to fly and record.

Also, make sure return to home setting is set to hover in case you loose signal. I have tested this and it works fine without GPS. I set to hover and turned off the RC and it just sat there in one place. Haven't tried it though with the setting set to return home. not sure what it would do without gps. But this discussion is about flying indoors and stability.

OK, second attempt with youtube made it public, This has not been edited and is my first flight with my M2Z indoors so it's kinda jerky and about 4am and the HVAC's have come back on to start cooling the place before we open at 6am

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[Ralph thompson]

Thanks Inno, thats funny, if Im in your area, now I know where the washrooms are and I like the friendly hand signals from the forklift driver.
Thats been a helpful discussion everyone, great pointers, thanks for your inputs, I feel much more comfortable about this job now.

 

[inno]

Thanks Inno, thats funny, if Im in your area, now I know where the washrooms are and I like the friendly hand signals from the forklift driver.
Thats been a helpful discussion everyone, great pointers, thanks for your inputs, I feel much more comfortable about this job now.

No prob Ralph, that's what this place is all about. Great group of folks and information. Just remember at 50' inside, your on your own as far as controlling your bird. Good Luck and safe flying!

 

[Meta4]

Why not take the drone out of doors to a wide open space, shield it if you can to minimise its exposure to gps signals prior to power up. Power it up once there and take off ASAP, before the drone gets it required compliment of GPS satellites, and see how high it will go?
That might save a lot of debate.

No need to debate.
It's much easier and quicker to look at what DJI say in the manual.
Here's the relevant from the Mavic 2 manual (p56).

Height is restricted to 16 ft (5 m) when the GPS signal is weak and Downward Vision System is activated. ​

Height is restricted to 98 ft (30 m) when the GPS signal is weak and Downward Vision System is inactivated.​

 

[Deleted member 103366]

That's why I mentioned page 57 of the manual (v2.0) in post #2.

 

[inno]

No need to debate.
It's much easier and quicker to look at what DJI say in the manual.
Here's the relevant from the Mavic 2 manual (p56).

Height is restricted to 16 ft (5 m) when the GPS signal is weak and Downward Vision System is activated. ​

Height is restricted to 98 ft (30 m) when the GPS signal is weak and Downward Vision System is inactivated.​

Hey Meta4,

After purchasing my 1st DJI P3A in 2015, I joined shortly after PhantomPilots rather than staying on DJI's forum which I started with. Folks here knew through their own trial and error learned a lot about the product and help others learn as well. They did not just read and re-state the DJI manuals but tested then shared that info contrary to what the manuals stated. They figured out what the software was doing and shared it. And I for one am very appreciative for that! Thank You! And as far as you are concerned, I have followed al of your informative threads since I joined. And if I'm not mistaken, you wrote a piece on how the compass and IMU sync up at start up and why the fly away's occur. Geat job!

Anyway No debate here, was just stating what I've done with my M2Z. I know what the doc states. DJI has done an ok job of documenting, but...

Specific details in their manuals about what their components are capable of doing is pretty dead on, however how their software uses them is another story.

Haven't myself hit the 98' mark inside a warehouse (non that I've been in are that high) and can't speak to it. But based on my flights I can reach with no warnings 25', 5 foot below the ceiling with only VPS.

Here is the ironic thing about all this, and based on DJI's manual...

1. If none or weak GPS and VPS working, you can fly up to 16'
2. If none or weak GPS and no VPS, you can fly up to 98'

The kicker for me is, if i only have VPS, 16' is the limit. But hey, let's turn off VPS and now I can go to 98', but this time with no help from the software to hold position other than altitude hold. I'm in ATTI mode. Don't fly past an air duct. And don't let go of your sticks.

In #2, when this occurs it puts you in ATTI mode, I flew this scenario outside today. Had to wrap a bunch of layers of tin foil around the nose which reduced the GPS sat count to 3 or less so it never got a lock, kept bouncing off then back to a 3 count. Turned off all the sensors including the RTH Obstacle sensing. Took off straight up but stopped at 150'. Got too breezy and difficult to hold position, then back down and landed.

So in a nut shell, I now what is says in the book but what it may do in real flying life is a different story.

Have a Great night and keep up your good work

thanks
inno