Re: Radar - was: Another speeding ticket question

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <199910101412.KAA14277@elektro.cmhnet.org> Charlie Smith writes:

> > My understanding of moving RADAR is that it takes a reading from a
> > stationary object, e.g. the road, to determine the speed of the cruiser and
> > compares it to the reading from the moving object, the victim, to determine
> > it's speed.  They are not hooked into the vehicles speedometer.

> Bob's right.

> The radar unit determines target speed by figuring the difference between
> background returned signals (stationary objects) and the returned signal
> from the target.

You guys obviously have a different system.  Over here, the system is
almost always used on vehicles moving in the _same_ direction.  The
scenario of a police vehicle turning to chase someone passing in the
other direction is unknown - you can't do a U-turn on a motorway anyway
because of the centre Armco barrier and because traffic densities are
just too high.

The vast majority of police vehicles here are now equipped with video -
some are fully digital, others blend in an optical image of the police
car's speedometer.  I don't know how they 'target' the vehicle whose
speed they want to measure, but they can do it from several hundred
yards in heavy traffic.

--
 Phil Payne
 UK Audi quattro Owners Club
 Phone: 07785 302803   Fax: 0870 0883933