[time-nuts] Need advice for multilateration setup

Attila Kinali attila at kinali.ch
Tue Apr 7 08:08:21 EDT 2015


On Mon, 06 Apr 2015 23:02:01 +0200
Magnus Danielson <magnus at rubidium.dyndns.org> wrote:

> You want to keep your chip-rate up to make the integer ambiguity of the 
> carrier phase simple. The carrier frequency divided by chipping rate 
> ratio indicate how difficult problem it is to solve (GPS L1 C/A code has 
> 1540). The 70 cm band has rather narrow allocations. The 23 cm band 
> allow for much wide allocations. The benefit of the 70 cm band is 
> naturally the easy of getting hardware.

Yes. But I would do carrier phase tracking only after code phase
tracking proved to be not accurate enough. Improving later and
switching to another band is relatively easy, once you've proven
that the system in principle works.

> Another benefit of a higher chipping rate is that it can allow for a 
> higher bandwidth, allowing for tighter tracking of the rocket dynamics.
> The chipping rate at some code legnth creates the maximum tracking rate, 
> and some fraction of that is the highest bandwidth tolerable.

That's a very good argument for higher chiping rates.

			Attila Kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
                 -- Miss Matheson, The Diamond Age, Neil Stephenson


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