If altitude is judged by barometric pressure, would altering the barometer's pressure reading before it's turned on affect perceived altitude?

[cgmaxed]

FOR YOUR CONSIDERATION: If a drone's height is calculated by the barometric pressure surrounding the drone at take off/ just before being turned on (a height determined to be zero by the barometer), it would seem possible, with a little ingenuity, to alter the barometer's perceived pressure just before being turned on, thus changing what the interpreted height actually is. Here is an example of how it could be done. --- Place your drone under an aquarium with a gasket on the bottom to seal the open end. This particular aquarium would have a sealed tube going through the side of it as well as a pressure release valve. To the tube you attach a negative pressure pump. Also attached and sealed to the side of the aquarium is a rod mechanism that will power the drone on only after a sufficient amount of air has been suctioned or removed from the aquarium. When the drone is turned on in this new low barometric pressure environment, it would zero itself or give a value of 0 ft. Now, while the drone is on and the barometer has zeroed itself, we slowly open the pressure release valve, letting in the higher pressure air outside of the aquarium to the inside. As you open the release valve, the pressure inside the tank goes up, thus the barometer would begin changing it's height value to a lower altitude. Let's say the experimenter put enough negative pressure in the aquarium to cause the barometer to interpret it's height as -400 ft, after he opened the pressure release valve and then removed the tank from over the drone. So now you have a drone sitting on the ground thinking it is at a -400ft. IS THIS POSSIBLE? It makes sense, if the altitude indicator is being controlled by a barometer if you ask me. THOUGHTS ANYONE. --From Mr Curious. Feel free to try the experiment if you have nothing better to do.

 

[sar104]

The altitude is reset at takeoff, so that's not going to work.

 

[slup]

Not possible with less than you take-off within that aquarium ... the barometric sensor is reset just after take-off.

Seen here in the DAT event log & corresponding position marked in the chart ... it happened in that flight at 1,31m ultrasonic height.

 

[BigAl07]

How would you turn the aircraft ON while inside the pressure chamber? It would have to have the "modified" pressure at time of the IMU start up to have the effect you're shooting for.

 

[Dawnvt]

Fascinating... I'm curious as to why you'd want to fool the barometer?

 

[Repaid1]

How would you turn the aircraft ON while inside the pressure chamber? It would have to have the "modified" pressure at time of the IMU start up to have the effect you're shooting for.

I don't believe so, but could be wrong. I don't believe it sets homepoint/"0" point altitude till arming motors at take off. Thus as post #3 states. So one would simply turn on aircraft first, place in vac chamber and engage pump and then arm at atmosphere desired, lift tank to show movement to IMU?

Take out of chamber and take flight? Heck I don't know...just another silly thing to ponder.

 

[Repaid1]

Fascinating... I'm curious as to why you'd want to fool the barometer?

There is only one reason (insert final jeopardy music here) Hint...what does the barometer control???

 

[Thomas B]

There is only one reason (insert final jeopardy music here) Hint...what does the barometer control???

Doubt if it will change the true altitude AGL even if it worked w/o major program hacking. JMHO.

 

[sar104]

I don't believe so, but could be wrong. I don't believe it sets homepoint/"0" point altitude till arming motors at take off. Thus as post #3 states. So one would simply turn on aircraft first, place in vac chamber and engage pump and then arm at atmosphere desired, lift tank to show movement to IMU?

Take out of chamber and take flight? Heck I don't know...just another silly thing to ponder.

It's not set on motor arm, it's set on takeoff.

 

[Repaid1]

It's not set on motor arm, it's set on takeoff.

So he needs a really tall tank then

 

[Rich QR]

It's not set on motor arm, it's set on takeoff.

Right. I can land on the roof of my house, take off, and fly back down to my back yard, and the drone will show a negative altitude. The zero reference point of the altitude is reset with each takeoff. So to make the scheme work, you'd have to take off inside the pressurized (or evacuated) aquarium, and maintain controlled flight while neutralizing the pressure difference and allowing the still-flying drone to escape the aquarium. Good luck with that!

 

[Repaid1]

Right. I can land on the roof of my house, take off, and fly back down to my back yard, and the drone will show a negative altitude. The zero reference point of the altitude is reset with each takeoff.

So kinda clarify that, You land on the roof and then what? You are sitting armed and "idling" and then just apply power and the barometer is zeroed or are you stopping props and rearming to lift off and then down? Cause if you stop props it doesn't quantify either case..but I already believe now it's right at liftoff anyway.

 

[Rich QR]

So kinda clarify that, You land on the roof and then what? You are sitting armed and "idling" and then just apply power and the barometer is zeroed or are you stopping props and rearming to lift off and then down? Cause if you stop props it doesn't quantify either case..but I already believe now it's right at liftoff anyway.

I said I land on the roof. My MM doesn't land without stopping the props. I thought all DJI drones were like that, but maybe I'm mistaken.

 

[lookout]

In long distance flight, barometer can change, it affects what appears to be altitude. Mostly if you stay at the same altitude the whole time, you'd just be staying in sync to adjust barometer. On a drone, it's only limited to a few hundred feet, could be problematic.

 

[DoomMeister]

On a drone, it's only limited to a few hundred feet, could be problematic.

Do you have specification data to qualify that statement? To my knowledge the barometers used in consumer grade drones can measure changes much greater than a few hundred feet.

 

[lookout]

Do you have specification data to qualify that statement? To my knowledge the barometers used in consumer grade drones can measure changes much greater than a few hundred feet.

I meant we can only operate the drones to about a few hundred feet.

 

[SkyeHigh]

Do you have specification data to qualify that statement? To my knowledge the barometers used in consumer grade drones can measure changes much greater than a few hundred feet.

You are correct. One of the most common barometric pressure sensors used in drones is the Bosch BMPx80 series and can accurately measure from way below sea level to 30,000ft (9KM).

 

[cgmaxed]

Looks like I'm gonna need a bigger tank. LOL. Like i'm gonna waste my time trying it. Sounds like a pain in the you know what..

 

[DoomMeister]

Looks like I'm gonna need a bigger tank. LOL. Like i'm gonna waste my time trying it. Sounds like a pain in the you know what..

What was the point of the exercise in the first place? If it was to exceed height limitations all you need to do is plug the hole to the sensor.

 

[Tolly]

FOR YOUR CONSIDERATION: If a drone's height is calculated by the barometric pressure surrounding the drone at take off/ just before being turned on (a height determined to be zero by the barometer), it would seem possible, with a little ingenuity, to alter the barometer's perceived pressure just before being turned on, thus changing what the interpreted height actually is. Here is an example of how it could be done. --- Place your drone under an aquarium with a gasket on the bottom to seal the open end. This particular aquarium would have a sealed tube going through the side of it as well as a pressure release valve. To the tube you attach a negative pressure pump. Also attached and sealed to the side of the aquarium is a rod mechanism that will power the drone on only after a sufficient amount of air has been suctioned or removed from the aquarium. When the drone is turned on in this new low barometric pressure environment, it would zero itself or give a value of 0 ft. Now, while the drone is on and the barometer has zeroed itself, we slowly open the pressure release valve, letting in the higher pressure air outside of the aquarium to the inside. As you open the release valve, the pressure inside the tank goes up, thus the barometer would begin changing it's height value to a lower altitude. Let's say the experimenter put enough negative pressure in the aquarium to cause the barometer to interpret it's height as -400 ft, after he opened the pressure release valve and then removed the tank from over the drone. So now you have a drone sitting on the ground thinking it is at a -400ft. IS THIS POSSIBLE? It makes sense, if the altitude indicator is being controlled by a barometer if you ask me. THOUGHTS ANYONE. --From Mr Curious. Feel free to try the experiment if you have nothing better to do.

LOL, why would you? Most bizarre thread I have ever read