RADAR Altimeter

[Andrew 0]

One of the difficulties with telemetry or altitude hold for a UAV(especially helicopter) is accurate altitude readings. Has anyone experimented with using RADAR altitude detection or is this something that is beyond the hobbyist?

The Mk IV unit in this link is accurate to 12.5cm.

http://www.roke.co.uk/aviation/miniature_r...r_altimeter.asp

Cool stuff no?

Edited January 16, 2004 by Andrew

[Mr.RC-Cam 126]

What does that gadget cost? It looks expensive.

[Andrew 0]

My guess is that it's definitely expensive. They make you request a price quote and don't have any pricing info on their website. Do you think it's possible to make a device to measure altitude using radar? Maybe adapt a radar gun sensor from measuring doppler shift(speed) to measuring distance?

Maybe hack one of these devices?

http://www.hobbytron.net/r-sg7.html

Edited January 16, 2004 by Andrew

[Mr.RC-Cam 126]

I was also thinking a radar gun would be a possible donor for the project. But I believe they all rely on the doppler effect (which does not readily offer distance measurements on static objects). We would want pulse echo ranging in order to get that sort of data.

The big issue is that you would have to rewrite the firmware. Perhaps dropping in a new microcontroller is all that is required, but I would expect some circuitry remodeling would be needed. The good news is that some of the hardware in the gun should be salvageable.

[elossam 0]

May be it´s a stupid suggest but why dont you start from something simmilar to that.

http://www.yorksurvey.co.uk/products/prods...find/dus20+.htm

[Mr.RC-Cam 126]

The acoustical method (ultrasound) might not work well in many R/C aircraft applications. It often will not work if there is excessive vibration or noise. Also, even under ideal situations, ranging is limited to a few dozen feet.

However, for quiet settings that need a few feet of ranging, ultrasound is king. It is very popular in robotics. It all depends on the exact application; I would imagine that in a nitro powered model, the radar method might be a better choice.

[Kilrah 2]

Yes, max range is usually 15-20m... only useful as an automatic landing aid...

I've also come across some laser devices which can range up to 150m, but inside of course.. with the ambient light they surely won't work...

[Andrew 0]

I've sent a price inquiry to the Roke folks. I'll let everyone know how much $$$ the unit costs when I find out.

[Mr.RC-Cam 126]

I'll let everyone know how much $$$ the unit costs when I find out.

Probably the "$$$" will be more like $,$$$.

[Andrew 0]

I won't be surprised if it's $$,$$$

[Andrew 0]

$8,241.27 ouch. That's not including the taxes and required export license. Might be a cool project to try to make one on your own, but unfortunately I lack the technical savvy that would require.

[Mr.RC-Cam 126]

I was afraid of that. I hear this gadget is used on the Mars rovers.

[cyber-flyer 1]

Check autonomous landing video of neural robotics chopper:

http://www.neural-robotics.com/videopage.htm

I wonder if there is a reason they land on pavement? It's possible they use ultrasonic finder which (my guess) is much better in reading distance to hard surfaces.

Regards,

Val.

[Andrew 0]

Here is a link to the manual for the speedy radar kit. Any ideas on if it's possible to adapt from speed measurements to distance? It runs at 2.6Ghz.

http://www.ramseyelectronics.com/downloads...manuals/SG7.pdf

[MikeDD 0]

Check autonomous landing video of neural robotics chopper:

http://www.neural-robotics.com/videopage.htm

I wonder if there is a reason they land on pavement? It's possible they use ultrasonic finder which (my guess) is much better in reading distance to hard surfaces.

Regards,

Val.

In the video text they say it is a ultrasonic device.