Re: Pulsar Nav accuracy

----- Original Message -----
From: "Hal" <hal@buffnet.net>

> Hello Folks,
>
> At present, we are using a 2 AU baseline for measurements of stars. 
Once
> we start using the ships of FT to place automated telescopes in orbit
> around the sun, we can expand the baseline easily enough.  Anyone care
to
> figure out what the accuracy will be for determining where stars
*were* if
> the baseline is now say, 40 AU's?

As a first back-of-the envelope guess, the error would be inversely
proportional to the baseline, so 2/40 = 1/20th ( 5% ) the present error.

> Also, how accurate does one's position have to be known to establish
where
> you are precisely?  In other words, if I for what ever reason, jump to
some
> unknown location in space, and I find at least 2 known pulsars -
wouldn't
> that establish the rough ball park of where I was to the extent that I
at
> least know which direction to jump back?

With two known pulsars, you know you are on a circle whose diameter is
your
distance to the line directly joining the pulsars - a pretty large bit
of
space. You need three pulsars (or other beacons).

I you know reasonably where you were heading would be back to an
accuracy
combining the accuracy with which you know the pulsar positions and your
original route.

Greetings