Ross wrote
> I am trying to set up a wireless location system in the range of about
> 20-30 metres.
> I plan on locating the person using ping over a wireless
> connection(802.11b)...
> The more acturate ping i can get the more acturately i can locate the
> person.....
>> Does any one know how to get ping times down to microseconds?
> Or a program that can do this?
Sorry to rain on your parade but if I were your advisor on this then right
off the top of my head I'd have to say "Find another project". Radio waves
travel ~ 300m / µsec so to get your accuracy down to 10% of your desired
range you'd need to be able to measure the RTT with nearly nanosecond
accuracy and there are so many other factors involved in a ping than simply
radio RTT that I just don't see how it would be feasible.
Even with a RTOS, which Linux is not, all you're guaranteed is that you'll
get a response to an interrupt within a predictable time. The only way to do
radio ranging is with dedicated hardware which knows what it's trying to do
and is designed accordingly. The basic principles were worked out 60+ years
ago - carry on from there :-)
Niall
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