Accurate Height(above sea level) Measurement Device

[Eng_Student]

Hi Guys

I am new engineering and would appreciate any advice or ideas on this project. I need to measure the height above sea level of a small vehicle that I am building..
My first idea was GPS, but the vehicle is going travel under a thick steel structure, so it will not work.
I thought about a pitot tube but there are many random gusts of wind, so the readings may be compromised. I need an accuracy of about 10mm.

Any input will be much appreciated.
Thanks!

 

[russ_watters]

You're going to find this to be a pretty tall order - neither GPS nor an altimeter would give you that kind of accuracy anyway.

 

[Eng_Student]

Thanks for your reply Russ.
A relative altitude would also do fine.

 

[FredGarvin]

A static pressure port connected to a large plenum should do the trick.

 

[berkeman]

Hi Guys

I am new engineering and would appreciate any advice or ideas on this project. I need to measure the height above sea level of a small vehicle that I am building..
My first idea was GPS, but the vehicle is going travel under a thick steel structure, so it will not work.
I thought about a pitot tube but there are many random gusts of wind, so the readings may be compromised. I need an accuracy of about 10mm.

Any input will be much appreciated.
Thanks!

Does this vehicle fly or roll? If it rolls, can you use an inclinometer and distance traveled to give you elevation change information?

 

[Eng_Student]

Thanks for your responses guys, I will be looking into them!

Berkeman: the vehicle rolls, so it is a good idea. However, the vehicle travels a complicated path through holes and over rocks etc, so the continuous computation might be tricky?

 

[Danger]

If this thing doesn't have to travel for really long distances, could you lay an RF transmitting cable along the path above ground at a known altitude and take readings from it?

 

[berkeman]

Thanks for your responses guys, I will be looking into them!

Berkeman: the vehicle rolls, so it is a good idea. However, the vehicle travels a complicated path through holes and over rocks etc, so the continuous computation might be tricky?

Not if you have a good inclinometer and don't lose traction at the wheels.

 

[Q_Goest]

Inertial navigation unit (INU) also called inertial navigation system.
http://en.wikipedia.org/wiki/Inertial_navigation_system

Buy one for a few thousand $
http://www.google.com/search?hl=en&q=inertial+navigation+system&aq=f&oq=&aqi=g10

 

[Mech_Engineer]

If you're flying under a steel structure, that tells me you're not very far off the ground- could you use some sort of laser rangefinding to the ground or structure above?