Bypass 8m height Limit with No GPS?

[Kristof.Bremen]

Hi,

Anyone know how to bypass the 8m height limit when flying indoors without GPS?

Maybe just putting some sticky tape on the optical sensors?

Regards
Chris

 

[E90RAW]

Hi,

Anyone know how to bypass the 8m height limit when flying indoors without GPS?

Maybe just putting some sticky tape on the optical sensors?

Regards
Chris

What drone? Put it into atti mode.

 

[Kristof.Bremen]

What drone? Put it into atti mode.

The dji Mavic mini.

 

[E90RAW]

The dji Mavic mini.

Not sure with the mini but with mavic 2 series you can put into sport mode which is ostensible atti mode or no sensors.

 

[scro]

Launch from a higher point if you can. That'll set the limit a bit higher. There's a barometric altimeter too, so that may restrict max height above launch point too.

 

[Kristof.Bremen]

So if you descend, can you return to the inital starting point?

I'm talking about 30 to 60 meters.

 

[scro]

I'm curious what you're planning to do!? It is not often that consumer grade drones are flown indoors with such height variations. If you have an indoor space this big have a play and see what you can/can't do and report back!

The VPS system works best at altitudes of 10m or less, and becomes quite unreliable beyond about 30m so you'll need to keep a close watch on the drone to be able to manually correct any drift.

 

[Kristof.Bremen]

Normally we carry out industrial inspections with Flyability ELIOS drones.

This time we fly underground in a salt mine (0% humidity).
Everything that comes in contact with normal air on the surface of the earth will be destroyed very quickly.
Unless we lose the drones, they will remain in the mine for future missions.

Therefore we cannot use our Flyability ELIOS drones and have bought two DJI Mavic Mini and are currently working on the modifications (very light cage, bright LED light powered by the flight battery).

Heavier drones are out of the question due to the dusty environment (more thrust).
(Technically speaking, a Phantom 4 would be perfect, but it is too heavy and probably raises too much dust.)

We also generally assume that the drone will eventually lose it, so we let a screen recorder run along.

 

[scro]

Interesting work! I was wondering if you were looking to use it in a cave or similar. The only place I've had the opportunity to fly 10m below takeoff point was outside where I had GPS. You could try putting aluminium foil over the top of the drone to shield the GPS antenna and force it to just use VPS or fly in ATTI mode to do some testing outside in the open before taking it into the mine. Also putting tape over the VPS sensors is the only current way of disabling them.

What sort of range would you need? The wifi signal may not propagate too far around corners, though the lack of humidity should help a little bit. The MM isn't really set up as an indoor inspection drone and the inability to modify the fairly restrictive firmware isn't helpful. If you want the VPS system to work you may need a downward pointing light too.

Have you seen the flymore kit prop cages? They are very light and cheap, but could maybe be improved on.

 

[Kristof.Bremen]

Hi,
800m (2600ft) underground we will have no issues with GPS
We will fly more or less in line of sight in a "space (25x65meters) (more or less "egg shaped", starting in the upper third.

I use the flymore combo prop cage as a basis for further mods and I use 24v high power led (with a tiny dc booster) on the front and the bottom of the drone (not because of VPS, but because we want to see something when looking downwards with the camera)

thanks a lot so far for your input!

 

[scro]

For me it's a really interesting application for drone technology, and I'd love to hear how you get on with this! Another thing worth considering is the MM has a fixed focus camera - things closer than about 1m start to get out of focus, so not ideal for close up inspection.

Good luck! I hope you have success!

 

[Kristof.Bremen]

Thanks for the info with them Camera! The Flyability ELIOS - afaik - has a fixed focus too, but with the mm we won't get that close, also because of dust.

I will come back and share my experience after the mission.

 

[Meta4]

Not sure with the mini but with mavic 2 series you can put into sport mode which is ostensible atti mode or no sensors.

Atti mode has no horizontal position holding ... Sport Mode does.
Sport mode is more like P-GPS mode with a bigger tilt angle.

 

[scro]

That doesn't spoof GPS. Rather, it supplies a dynamic correction to standard GPS by using a second GPS receiver at a fixed, known location. By cross referencing the 2 GPS outputs a lot of error can be filtered out. It is very common to use this for civil engineering surveys and positioning for onshore and marine construction where standard GPS is not accurate enough

It could be applied to drones, and probably is in some industrial applications, but the drone itself would still need to receive GPS signals. So - not really helpful when down underground in a mine, as per where the OP is hoping to use his drone. A more useful technology would be to use a form of total station machine control if precise location data is required.

 

[E90RAW]

Atti mode has no horizontal position holding ... Sport Mode does.
Sport mode is more like P-GPS mode with a bigger tilt angle.

I have used my M2P inside with no GPS signal in sport mode to evaluate our high ceilings(30 foot) and had no issues other than the currents the drone creates. It was surprisingly stable even as close as 1 foot from the walls. Certainly there was drift without the sensors and GPS.

 

[scro]

Sport mode on the Mini is different to sport mode on the MP2.

On the Mini, sport mode does not disable any sensors, as per @Meta4 's post. In sports mode the Mini will continue to use GPS and VPS if possible. It has no other OA sensors to be able to disable them.

 

[Cw4bray]

I had the same problem, inside a concrete grain elevator.

 

[EyesWideShut]

Therefore we cannot use our Flyability ELIOS drones and have bought two DJI Mavic Mini and are currently working on the modifications (very light cage, bright LED light powered by the flight battery).

Probably because of the 24v LEDs, sounds like you are trying to keep the weight down as low as possible with you modifying a prop guard cage and using the mini's battery. Since you don't need the GPS you might lose some weight by physically removing.

Not sure if you are going to cover the bottom VPS sensors or use them for positioning since you have a bottom light but maybe they could be removed to save a little weight too rather than adding tape.

Hope you let us know how it all goes.

 

[Kristof.Bremen]

I had the same problem, inside a concrete grain elevator.

Did you find a workaround / fix?

 

[Kristof.Bremen]

Probably because of the 24v LEDs, sounds like you are trying to keep the weight down as low as possible with you modifying a prop guard cage and using the mini's battery. Since you don't need the GPS you might lose some weight by physically removing.

Not sure if you are going to cover the bottom VPS sensors or use them for positioning since you have a bottom light but maybe they could be removed to save a little weight too rather than adding tape.

Hope you let us know how it all goes.

Hi, thanks for the good advice.

I once removed a GPS antenna from a Mavic Air - worked well. But removing the VPS sensors could cause issues with the electronics I think.

The biggest problem with those "consumer" drones is the flight controller software, even a slightly crash causes all motors to stop.