Re: [Paparazzi-devel] distance measurement for landing.

[Andrew S]

Hi Joe.
i am interested in UWB radar too, could you tell me some words at greater 
length?
We are working on 20 kg helicopter, and now selecting some of radio altimeter..
Thanks in advance, Andrew

06.11.09, 21:23, "gisela.noci" <address@hidden>:

> Have tried this type of sensor - useless - does not work at all over grass,
> nor over desert gravel/sand mix. Ok over tarmac runway, up to maybe 2meters
> - not really a reliable option at all - really needs good surface
> reflectivity
> I do autoland using ultrasonic sensors - 4 Murata MA40B8S transducers pulsed
> in parallel with 55volts Peak to Peak, and 1 MA40B8R as receiver sensor, in
> an own designed circuit. This works very well, giving 8 meter reliable
> detection over almost any bad terrain, except tall grass ( tall = more than
> 500mm). Over Tarmac range is about 13meters. Uses a PIC processor. 
> You need LOTS of TX energy, hence 4 transducers hammered at the max voltage.
> The LV-MAXSONAR EZ series are as useless - just not enough energy for
> surfaces with low reflectivity. 
>  I am working on a UWB radar ranger, which is really the answer - 2 watts
> power consumption will give range from 200mm to 1200meters, the hassle is
> antenna space needed - will not work on your average flying wing type A/C,
> but great on a 60 size trainer or similar.
> Don't waste your money on the Infra Red route...
> Joe
> -----Original Message-----
> From: address@hidden
> [mailto:address@hidden
> ] On Behalf Of Chris
> Sent: Friday, November 06, 2009 7:42 PM
> To: address@hidden
> Subject: [Paparazzi-devel] distance measurement for landing.
> Hi.
> I would like to hear any opinions on those sensors:
> http://www.acroname.com/robotics/parts/R302-GP2Y0A700K0F.html
> and
> http://www.acroname.com/robotics/parts/R144-GP2Y0A02YK.html
> They look interesting and i am tempted to try and add them to the paparazzi.
> Which one should you choose?
> Chris
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