Andrew 0 Report post Posted January 16, 2004 (edited) 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 Share this post Link to post Share on other sites
Mr.RC-Cam 123 Report post Posted January 16, 2004 What does that gadget cost? It looks expensive. Share this post Link to post Share on other sites
Andrew 0 Report post Posted January 16, 2004 (edited) 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 Share this post Link to post Share on other sites
Mr.RC-Cam 123 Report post Posted January 16, 2004 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. Share this post Link to post Share on other sites
elossam 0 Report post Posted January 16, 2004 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 Share this post Link to post Share on other sites
Mr.RC-Cam 123 Report post Posted January 17, 2004 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. Share this post Link to post Share on other sites
Kilrah 2 Report post Posted January 17, 2004 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... Share this post Link to post Share on other sites
Andrew 0 Report post Posted January 18, 2004 I've sent a price inquiry to the Roke folks. I'll let everyone know how much $$$ the unit costs when I find out. Share this post Link to post Share on other sites
Mr.RC-Cam 123 Report post Posted January 18, 2004 I'll let everyone know how much $$$ the unit costs when I find out. Probably the "$$$" will be more like $,$$$. Share this post Link to post Share on other sites
Andrew 0 Report post Posted January 18, 2004 I won't be surprised if it's $$,$$$ Share this post Link to post Share on other sites
Andrew 0 Report post Posted January 21, 2004 $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. Share this post Link to post Share on other sites
Mr.RC-Cam 123 Report post Posted January 21, 2004 I was afraid of that. I hear this gadget is used on the Mars rovers. Share this post Link to post Share on other sites
cyber-flyer 1 Report post Posted January 21, 2004 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. Share this post Link to post Share on other sites
Andrew 0 Report post Posted January 23, 2004 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 Share this post Link to post Share on other sites
MikeDD 0 Report post Posted January 26, 2004 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. Share this post Link to post Share on other sites
