Article View: sci.electronics
Article #14413Re: measuring vehicle speed
From: WATERS,CLYDE GORDON
Date: Sun, 23 Jun 1991 23:14
Date: Sun, 23 Jun 1991 23:14
40 lines
2637 bytes
2637 bytes
In article <10922@plains.NoDak.edu> csmith@plains.NoDak.edu (Carl Smith) writes:
>In article <4746@guppie4.UUCP> svoboda@motcid.UUCP (David Svoboda) writes:
>>From article <1991Jun20.024446.18473@en.ecn.purdue.edu>, by jbs@en.ecn.purdue.edu (Spaggie):
>>> [description of laser speckle patter speed measurement system deleted]
>>Outstanding. But I could envision a problem with an inconsistant ground
>>surface, as well as a problem illuminating the ground sufficiently from
>>under the car to be picked up reliably by the receiver.
>Anything that has a direct "view" of the road surface will soon be
>covered with a layer of dirt, even if the road isn't wet and muddy.
>Laser beams don't go far through mud.
>I don't know how this could be solved... Maybe mount the laser and
>detector behind a glass window with a little window wiper... :)
I made a suggestion to the original poster that I will share here due
to the apparent interest:
I read a while back about how F1 racing teams wanted to have info on
car-ground speed, ride height, etc. Their method seemed a little more
practical-
They used an ultrasound source (I think) and bounced sound off the ground.
The transmitter was surrounded by little directional recievers (mics?)
The time the beam took to come back compared to the shift laterally or
longitudinally of the beam reflected referenced to the original transmission
position can easily be used to calculate vehicle speed (a simple ratio)
This should be usable, if the transmission pulses are fast enough, to
not only give ground speed, but ride height in relation to time also.
I have no idea how the reception worked, but I think the transmitter was
placed in a small waveguide tube.(to concentrate the beam into a small
area) Anyone with more knowledge on ultrasound mapping could be of
much more help.
Regards,
Gordon.
--
WATERS,CLYDE GORDON-Georgia Institute of Technology Atlanta Ga 30332
******<LANGUAGE IS A VIRUS! - Laurie Anderson-Home of the Brave>*******
uucp: ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!gt0869a
Internet: gt0869a@prism.gatech.edu
Technical Details
Message-ID:
<31696@hydra.gatech.EDU>Path:
arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!usenet.ins.cwru.edu!gatech!prism!gt0869aReferences:
<1991Jun20.024446.18473@en.ecn.purdue.edu> <4746@guppie4.UUCP> <10922@plains.NoDak.edu>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!magnus.acs.ohio-state.edu!usenet.ins.cwru.edu!gatech!prism!gt0869a From: gt0869a@prism.gatech.EDU (WATERS,CLYDE GORDON) Newsgroups: sci.electronics Subject: Re: measuring vehicle speed Message-ID: <31696@hydra.gatech.EDU> Date: 23 Jun 91 23:14:23 GMT References: <1991Jun20.024446.18473@en.ecn.purdue.edu> <4746@guppie4.UUCP> <10922@plains.NoDak.edu> Organization: Georgia Institute of Technology Lines: 40