Re: FreightCorp Radios

[Matthew Geier <matthew@law.usyd.edu.au>]

David Johnson wrote:
> 
> tezza wrote:
> 
> > Supposed to be accurate to within 100 metres
> > (the system to be used, not GPS in general)
> 
> Civilian GPS is accurate to within 100 metres.  Military GPS is accurate to
> within 10 metres.

 There are a couple of projects on the go in the US under the name of
'Positive train seperation' that uses digital radio and GPS to provide
at lease some early warning that two trains might collide. They intend,
at least initially, it be an overlay of the safeworking system in use as
a check against errors.
 Where greater accuracy is required , ie sidings, loops and the like,
track beacons provide the extra data GPS doesnt have the resolution to
provide.
 By making it a non-vital overlay system they hope it will be cheap
enough to deploy widely, and it doesnt take to many accidents averted to
pay for it.

-- 
Matthew Geier,                          matthew@law.usyd.edu.au
Computer Systems Manager,               +61 2 9351 0240
Law School, University of Sydney        +61 2 9351 0200 (fax)