[talk-au] new toy found by son

John Smith deltafoxtrot256 at gmail.com
Thu Oct 1 14:24:05 BST 2009


2009/10/1 Elizabeth Dodd <edodd at billiau.net>:
> On Thu, 1 Oct 2009, John Smith wrote:
>> > On Thu, 1 Oct 2009, John Smith wrote:
>> >> Oh that's easy then, get him to figure out how to semi-sync with the
>> >> secondary GPS frequency, which is what high end surveying equipment
>> >> does, you don't need to lock onto the signal, just get close enough to
>> >> calculate the atmospheric effects on the L1 signal, and do it cheaply
>> >> enough we can get less than 1m accuracy with consumer grade kit :D
>> >
>> > he's not using a D-GPS setup
>>
>> Using both GPS freq's isn't D-GPS, the biggest unknown with the
>> regular GPS signal is delays in the ionosphere, being able to
>> establish that using the secondary/military GPS freq takes out the
>> uncertainity and you get a much more accurate signal
> because i proof read and edit the manuscripts i get all of this already,
> however it ain't accurate enough in heavy vegetation cover or any of the usual
> places where mtb trails are

What about designing a portable D-GPS unit?

These you can get to transmit, and add either bi-directional amps or
bigger antenna, you just put 2 or 3 of them up and then use a wifi
device based device, like a phone, to figure out it's position.

Although if you used 900Mhz band instead of 2.4Ghz you'd have greater range.




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